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2.4.1.386

Relevance: 100%

Accepted name:

GlcNAc-β-1,3-Gal β-1,6-N-acetylglucosaminyltransferase (distally acting)

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-β-D-GlcNAc-R = UDP + β-D-GlcNAc-(1→3)-[β-D-GlcNAc-(1→6)]-β-D-Gal-(1→4)-β-D-GlcNAc-R

Other name(s):

UDP-GlcNAc:GlcNAcβ1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase; dIGnT; C2GnT2 (misleading)

Systematic name:

UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminide 6-β-N-acetylglucosaminyltransferase (configuration-inverting)

Comments:

Involved in the production of milk oligosaccharides in the lacto-N-triose (LNT) series. Cf. EC 2.4.1.150 (N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase; cIGnT) and EC 2.4.1.148 (acetylgalactosaminyl-O-glycosyl-glycoprotein β-1,6-N-acetylglucosaminyltransferase).

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 85638-40-0

References:

1.	Piller, F., Cartron, J.P., Maranduba, A., Veyrieres, A., Leroy, Y. and Fournet, B. Biosynthesis of blood group I antigens. Identification of a UDP-GlcNAc:GlcNAc β1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase in hog gastric mucosa. J. Biol. Chem. 259 (1984) 13385–13390. [PMID: 6490658]
2.	Yeh, J.C., Ong, E. and Fukuda, M. Molecular cloning and expression of a novel β-1,6-N-acetylglucosaminyltransferase that forms core 2, core 4, and I branches. J. Biol. Chem. 274 (1999) 3215–3221. [DOI] [PMID: 9915862]

[EC 2.4.1.386 created 2021]

3.2.1.140

Relevance: 99.5%

Accepted name:

lacto-N-biosidase

Reaction:

β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc + H₂O = β-D-Gal-(1→3)-D-GlcNAc + β-D-Gal-(1→4)-D-Glc

Glossary:

β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc = lacto-N-tetraose
β-D-Gal-(1→3)-D-GlcNAc = lacto-N-biose
β-D-Gal-(1→4)-D-Glc = lactose

Systematic name:

oligosaccharide lacto-N-biosylhydrolase

Comments:

The enzyme from Streptomyces specifically hydrolyses the terminal lacto-N-biosyl residue (β-D-Gal-(1→3)-D-GlcNAc) from the non-reducing end of oligosaccharides with the structure β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→R). Lacto-N-hexaose (β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is hydrolysed to form first lacto-N-tetraose plus lacto-N-biose, with the subsequent formation of lactose. Oligosaccharides in which the non-reducing terminal Gal or the penultimate GlcNAc are replaced by fucose or sialic acid are not substrates. Asialo GM1 tetraose (β-D-Gal-(1→3)-β-D-GalNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is hydrolysed very slowly, but lacto-N-neotetraose (β-D-Gal-(1→4)-β-D-GalNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is not a substrate

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 146359-52-6

References:

1.	Sano, M., Hayakawa, K., Kato, I. An enzyme releasing lacto-N-biose from oligosaccharides. Proc. Natl. Acad. Sci. USA 89 (1992) 8512–8516. [DOI] [PMID: 1528855]
2.	Sano, M., Hayakawa, K., Kato, I. Purification and characterization of an enzyme releasing lacto-N-biose from oligosaccharides with type 1 chain. J. Biol. Chem. 268 (1993) 18560–18566. [PMID: 7689556]

[EC 3.2.1.140 created 1999]

2.4.1.201

Relevance: 93.1%

Accepted name:

α-1,6-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here

Other name(s):

MGAT4C (gene name); N-acetylglucosaminyltransferase VI; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase VI; uridine diphosphoacetylglucosamine-glycopeptide β-1→4-acetylglucosaminyltransferase VI; mannosyl-glycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTVI; GlcNAc-T VI; UDP-N-acetyl-D-glucosamine:2,6-bis(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→6)-[N-acetyl-β-D-glucosaminyl-(1→2)]-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

Requires a high concentration of Mn²⁺ for maximal activity. The enzyme, characterized from hen oviduct membranes, participates in the processing of N-glycans in the Golgi apparatus. It transfers GlcNAc in β1-4 linkage to a D-mannose residue that already has GlcNAc residues attached at positions 2 and 6 by β linkages. No homologous enzyme appears to exist in mammals.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 119699-68-2

References:

1.	Brockhausen, I., Hull, E., Hindsgaul, O., Schachter, H., Shah, R.N., Michnick, S.W. and Carver, J.P. Control of glycoprotein synthesis. Detection and characterization of a novel branching enzyme from hen oviduct, UDP-N-acetylglucosamine:GlcNAc β1-6 (GlcNAc β1-2)Man α-R (GlcNAc to Man) β-4-N-acetylglucosaminyltransferase VI. J. Biol. Chem. 264 (1989) 11211–11221. [PMID: 2525556]
2.	Taguchi, T., Ogawa, T., Inoue, S., Inoue, Y., Sakamoto, Y., Korekane, H. and Taniguchi, N. Purification and characterization of UDP-GlcNAc:GlcNAcβ1-6(GlcNAcβ1-2)Manα1-R [GlcNAc to Man]-β1,4-N-acetylglucosaminyltransferase VI from hen oviduct. J. Biol. Chem. 275 (2000) 32598–32602. [DOI] [PMID: 10903319]
3.	Sakamoto, Y., Taguchi, T., Honke, K., Korekane, H., Watanabe, H., Tano, Y., Dohmae, N., Takio, K., Horii, A. and Taniguchi, N. Molecular cloning and expression of cDNA encoding chicken UDP-N-acetyl-D-glucosamine (GlcNAc): GlcNAcβ 1-6(GlcNAcβ 1-2)- manα 1-R[GlcNAc to man]β 1,4N-acetylglucosaminyltransferase VI. J. Biol. Chem. 275 (2000) 36029–36034. [DOI] [PMID: 10962001]

[EC 2.4.1.201 created 1992, modified 2001, modified 2018]

2.4.1.163

Transferred entry:

β-galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,3-acetylglucosaminyltransferase, now included in EC 2.4.1.149, N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase

[EC 2.4.1.163 created 1989, deleted 2016]

2.4.1.144

Relevance: 88.5%

Accepted name:

β-1,4-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-[β-D-GlcNAc-(1→4)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here

Other name(s):

N-acetylglucosaminyltransferase III; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase III; uridine diphosphoacetylglucosamine-glycopeptide β4-acetylglucosaminyltransferase III; β-1,4-mannosyl-glycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTIII; GlcNAc-T III; MGAT3 (gene name); UDP-N-acetyl-D-glucosamine:β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. The residue added by the enzyme at position 4 of the β-linked mannose of the trimannosyl core of N-glycans is known as a bisecting GlcNAc. Unlike GlcNAc residues added to other positions, it is not extended or modified. In addition, its presence prevents the action of other branching enzymes involved in the process such as GlcNAc-T IV (EC 2.4.1.145) and GlcNAc-T V (EC 2.4.1.155), and thus increased activity of GlcNAc-T III leads to a decrease in highly branched N-glycan structures.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 83744-93-8

References:

1.	Narasimhan, S. Control of glycoprotein synthesis. UDP-GlcNAc:glycopeptide β4-N-acetylglucosaminyltransferase III, an enzyme in hen oviduct which adds GlcNAc in β1-4 linkage to the β-linked mannose of the trimannosyl core of N-glycosyl oligosaccharides. J. Biol. Chem. 257 (1982) 10235–10242. [PMID: 6213618]
2.	Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
3.	Brockhausen, I., Carver, J.P. and Schachter, H. Control of glycoprotein synthesis. The use of oligosaccharide substrates and HPLC to study the sequential pathway for N-acetylglucosaminyltransferases I, II, III, IV, V, and VI in the biosynthesis of highly branched N-glycans by hen oviduct membranes. Biochem. Cell Biol. 66 (1988) 1134–1151. [PMID: 2975180]
4.	Nishikawa, A., Ihara, Y., Hatakeyama, M., Kangawa, K. and Taniguchi, N. Purification, cDNA cloning, and expression of UDP-N-acetylglucosamine: β-D-mannoside β-1,4N-acetylglucosaminyltransferase III from rat kidney. J. Biol. Chem. 267 (1992) 18199–18204. [PMID: 1325461]
5.	Ihara, Y., Nishikawa, A., Tohma, T., Soejima, H., Niikawa, N. and Taniguchi, N. cDNA cloning, expression, and chromosomal localization of human N-acetylglucosaminyltransferase III (GnT-III). J. Biochem. 113 (1993) 692–698. [PMID: 8370666]

[EC 2.4.1.144 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]

2.4.1.155

Relevance: 87.7%

Accepted name:

α-1,6-mannosyl-glycoprotein 6-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here

Other name(s):

MGAT5 (gene name); N-acetylglucosaminyltransferase V; α-mannoside β-1,6-N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-mannoside β1→6-acetylglucosaminyltransferase; UDP-N-acetylglucosamine:α-mannoside-β1,6 N-acetylglucosaminyltransferase; α-1,3(6)-mannosylglycoprotein β-1,6-N-acetylglucosaminyltransferase; GnTV; GlcNAc-T V; UDP-N-acetyl-D-glucosamine:6-[2-(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl]-glycoprotein 6-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)-β-D-mannosyl-glycoprotein 6-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

Requires Mg²⁺. The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. It catalyses the addition of N-acetylglucosamine in β 1-6 linkage to the α-linked mannose of biantennary N-linked oligosaccharides, and thus enables the synthesis of tri- and tetra-antennary complexes.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 83588-90-3

References:

1.	Cummings, R.D., Trowbridge, I.S. and Kornfeld, S. A mouse lymphoma cell line resistant to the leukoagglutinating lectin from Phaseolus vulgaris is deficient in UDP-GlcNAc: α-D-mannoside β1,6 N-acetylglucosaminyltransferase. J. Biol. Chem. 257 (1982) 13421–13427. [PMID: 6216250]
2.	Hindsgaul, O., Tahir, S.H., Srivastava, O.P. and Pierce, M. The trisaccharide β-D-GlcpNAc-(1→2)-α-D-Manp-(1→6)-β-D-Manp, as its 8-methoxycarbonyloctyl glycoside, is an acceptor selective for N-acetylglucosaminyltransferase V. Carbohydr. Res. 173 (1988) 263–272. [DOI] [PMID: 2834054]
3.	Shoreibah, M.G., Hindsgaul, O. and Pierce, M. Purification and characterization of rat kidney UDP-N-acetylglucosamine: α-6-D-mannoside β-1,6-N-acetylglucosaminyltransferase. J. Biol. Chem. 267 (1992) 2920–2927. [PMID: 1531335]
4.	Gu, J., Nishikawa, A., Tsuruoka, N., Ohno, M., Yamaguchi, N., Kangawa, K. and Taniguchi, N. Purification and characterization of UDP-N-acetylglucosamine: α-6-D-mannoside β 1-6N-acetylglucosaminyltransferase (N-acetylglucosaminyltransferase V) from a human lung cancer cell line. J. Biochem. 113 (1993) 614–619. [PMID: 8393437]
5.	Park, C., Jin, U.H., Lee, Y.C., Cho, T.J. and Kim, C.H. Characterization of UDP-N-acetylglucosamine:α-6-D-mannoside β-1,6-N-acetylglucosaminyltransferase V from a human hepatoma cell line Hep3B. Arch. Biochem. Biophys. 367 (1999) 281–288. [PMID: 10395745]
6.	Saito, T., Miyoshi, E., Sasai, K., Nakano, N., Eguchi, H., Honke, K. and Taniguchi, N. A secreted type of β 1,6-N-acetylglucosaminyltransferase V (GnT-V) induces tumor angiogenesis without mediation of glycosylation: a novel function of GnT-V distinct from the original glycosyltransferase activity. J. Biol. Chem. 277 (2002) 17002–17008. [PMID: 11872751]

[EC 2.4.1.155 created 1986, modified 2001, modified 2018]

2.4.1.145

Relevance: 86.6%

Accepted name:

α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here

Other name(s):

N-acetylglucosaminyltransferase IV; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IV; β-acetylglucosaminyltransferase IV; uridine diphosphoacetylglucosamine-glycopeptide β4-acetylglucosaminyltransferase IV; α-1,3-mannosylglycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTIV; UDP-N-acetyl-D-glucosamine:3-[2-(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl]-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

Requires Mn²⁺. The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. By adding a glucosaminyl residue to biantennary N-linked glycans, it enables the synthesis of tri- and tetra-antennary complexes.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 86498-16-0

References:

1.	Gleeson, P.A. and Schachter, H. Control of glycoprotein synthesis. J. Biol. Chem. 258 (1983) 6162–6173. [PMID: 6222042]
2.	Oguri, S., Minowa, M.T., Ihara, Y., Taniguchi, N., Ikenaga, H. and Takeuchi, M. Purification and characterization of UDP-N-acetylglucosamine: α1,3-D-mannoside β1,4-N-acetylglucosaminyltransferase (N-acetylglucosaminyltransferase-IV) from bovine small intestine. J. Biol. Chem. 272 (1997) 22721–22727. [DOI] [PMID: 9278430]
3.	Minowa, M.T., Oguri, S., Yoshida, A., Hara, T., Iwamatsu, A., Ikenaga, H. and Takeuchi, M. cDNA cloning and expression of bovine UDP-N-acetylglucosamine: α1, 3-D-mannoside β1,4-N-acetylglucosaminyltransferase IV. J. Biol. Chem. 273 (1998) 11556–11562. [DOI] [PMID: 9565571]
4.	Yoshida, A., Minowa, M.T., Takamatsu, S., Hara, T., Oguri, S., Ikenaga, H. and Takeuchi, M. Tissue specific expression and chromosomal mapping of a human UDP-N-acetylglucosamine: α1,3-d-mannoside β1, 4-N-acetylglucosaminyltransferase. Glycobiology 9 (1999) 303–310. [DOI] [PMID: 10024668]
5.	Yoshida, A., Minowa, M.T., Takamatsu, S., Hara, T., Ikenaga, H. and Takeuchi, M. A novel second isoenzyme of the human UDP-N-acetylglucosamine:α1,3-D-mannoside β1,4-N-acetylglucosaminyltransferase family: cDNA cloning, expression, and chromosomal assignment. Glycoconj. J. 15 (1998) 1115–1123. [PMID: 10372966]
6.	Takamatsu, S., Antonopoulos, A., Ohtsubo, K., Ditto, D., Chiba, Y., Le, D.T., Morris, H.R., Haslam, S.M., Dell, A., Marth, J.D. and Taniguchi, N. Physiological and glycomic characterization of N-acetylglucosaminyltransferase-IVa and -IVb double deficient mice. Glycobiology 20 (2010) 485–497. [DOI] [PMID: 20015870]

[EC 2.4.1.145 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]

2.4.2.38

Relevance: 85.8%

Accepted name:

glycoprotein 2-β-D-xylosyltransferase

Reaction:

UDP-α-D-xylose + N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] = UDP + N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-[β-D-Xyl-(1→2)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein]

For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here

Other name(s):

β1,2-xylosyltransferase; UDP-D-xylose:glycoprotein (D-xylose to the 3,6-disubstituted mannose of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 2-β-D-xylosyltransferase; UDP-D-xylose:glycoprotein (D-xylose to the 3,6-disubstituted mannose of N⁴-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 2-β-D-xylosyltransferase

Systematic name:

UDP-α-D-xylose:N⁴-{β-D-GlcNAc-(1→2)-α-D-mannosyl-(1→3)-[β-D-GlcNAc-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 2-β-D-xylosyltransferase (configuration-inverting)

Comments:

Specific for N-linked oligosaccharides (N-glycans).

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 141256-56-6

References:

1.	Zeng, Y., Bannon, G., Thomas, V.H., Rice, K., Drake, R. and Elbein, A. Purification and specificity of β1,2-xylosyltransferase, an enzyme that contributes to the allergenicity of some plant proteins. J. Biol. Chem. 272 (1997) 31340–31347. [DOI] [PMID: 9395463]
2.	Strasser, R., Mucha, J., Mach, L., Altmann, F., Wilson, I.B., Glössl, J. and Steinkellner, H. Molecular cloning and functional expression of β1,2-xylosyltransferase cDNA from Arabidopsis thaliana. FEBS Lett. 472 (2000) 105–108. [DOI] [PMID: 10781814]

[EC 2.4.2.38 created 2001]

2.4.1.164

Transferred entry:

galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,6-N-acetylglucosaminyltransferase, now included with EC 2.4.1.150, N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase

[EC 2.4.1.164 created 1989, deleted 2016]

2.4.1.150

Relevance: 84.2%

Accepted name:

N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-β-D-GlcNAc-R = UDP + β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-[β-D-GlcNAc-(1→6)]-β-D-Gal-(1→4)-β-D-GlcNAc-R

Glossary:

β-D-galactosyl-(1→4)-N-acetyl-D-glucosaminyl-R = type 2 precursor disaccharide

Other name(s):

GCNT2 (gene name); GCNT3 (gene name); IGnT; I-branching β1,6-N-acetylglucosaminyltransferase; N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-acetyllactosaminide β1→6-acetylglucosaminyltransferase; Galβ1→4GlcNAc-R β1→6 N-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-1,4-N-acetyl-D-glucosaminide β-1,6-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminide 6-β-N-acetylglucosaminyltransferase (configuration-inverting)

Comments:

The enzyme acts on poly-N-acetyllactosamine [glycan chains of β-D-galactosyl-(1→4)-N-acetyl-D-glucosamine units connected by β(1,3) linkages] attached to proteins or lipids. It transfers a GlcNAc residue by β(1,6)-linkage to galactosyl residues close to non-reducing terminals, introducing a branching pattern known as I branching.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 85638-40-0

References:

1.	Van den Eijnden, D.H., Winterwerp, H., Smeeman, P. and Schiphorst, W.E.C.M. Novikoff ascites tumor cells contain N-acetyllactosaminide β1→3 and β1→6 N-acetylglucosaminyltransferase activity. J. Biol. Chem. 258 (1983) 3435–3437. [PMID: 6219989]
2.	Basu, M. and Basu, S. Biosynthesis in vitro of Ii core glycosphingolipids from neolactotetraosylceramide by β 1-3- and β 1-6-N-acetylglucosaminyltransferases from mouse T-lymphoma. J. Biol. Chem. 259 (1984) 12557–12562. [PMID: 6238026]
3.	Piller, F., Cartron, J.P., Maranduba, A., Veyrieres, A., Leroy, Y. and Fournet, B. Biosynthesis of blood group I antigens. Identification of a UDP-GlcNAc:GlcNAc β1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase in hog gastric mucosa. J. Biol. Chem. 259 (1984) 13385–13390. [PMID: 6490658]
4.	Bierhuizen, M.F., Maemura, K., Kudo, S. and Fukuda, M. Genomic organization of core 2 and I branching β-1,6-N-acetylglucosaminyltransferases. Implication for evolution of the β-1,6-N-acetylglucosaminyltransferase gene family. Glycobiology 5 (1995) 417–425. [DOI] [PMID: 7579796]
5.	Ujita, M., McAuliffe, J., Suzuki, M., Hindsgaul, O., Clausen, H., Fukuda, M.N. and Fukuda, M. Regulation of I-branched poly-N-acetyllactosamine synthesis. Concerted actions by I-extension enzyme, I-branching enzyme, and β1,4-galactosyltransferase I. J. Biol. Chem. 274 (1999) 9296–9304. [DOI] [PMID: 10092606]
6.	Yeh, J.C., Ong, E. and Fukuda, M. Molecular cloning and expression of a novel β-1,6-N-acetylglucosaminyltransferase that forms core 2, core 4, and I branches. J. Biol. Chem. 274 (1999) 3215–3221. [DOI] [PMID: 9915862]

[EC 2.4.1.150 created 1984 (EC 2.4.1.164 created 1989, incorporated 2016), modified 2017]

2.4.1.132

Relevance: 82.1%

Accepted name:

GDP-Man:Man₁GlcNAc₂-PP-dolichol α-1,3-mannosyltransferase

Reaction:

GDP-α-D-mannose + β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = GDP + α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Glossary:

β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = β-D-mannosyl-(1→4)-N,N′-diacetylchitobiosyldiphosphodolichol

Other name(s):

Alg2 mannosyltransferase (ambiguous); ALG2 (gene name, ambiguous); glycolipid 3-α-mannosyltransferase; GDP-mannose:glycolipid 3-α-D-mannosyltransferase; GDP-Man:Man₁GlcNAc₂-PP-Dol α-1,3-mannosyltransferase; GDP-D-mannose:D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 3-α-mannosyltransferase

Systematic name:

GDP-α-D-mannose:β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-mannosyltransferase (configuration-retaining)

Comments:

The biosynthesis of asparagine-linked glycoproteins utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. Alg2 mannosyltransferase from Saccharomyces cerevisiae carries out an α1,3-mannosylation of D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol, followed by an α1,6-mannosylation (cf. EC 2.4.1.257), to form the first branched pentasaccharide intermediate of the dolichol pathway [1,2].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 81181-76-2

References:

1.	Kampf, M., Absmanner, B., Schwarz, M. and Lehle, L. Biochemical characterization and membrane topology of Alg2 from Saccharomyces cerevisiae as a bifunctional α1,3- and 1,6-mannosyltransferase involved in lipid-linked oligosaccharide biosynthesis. J. Biol. Chem. 284 (2009) 11900–11912. [DOI] [PMID: 19282279]
2.	O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]

[EC 2.4.1.132 created 1984, modified 2011, modified 2012]

2.4.1.267

Relevance: 81.9%

Accepted name:

dolichyl-P-Glc:Man₉GlcNAc₂-PP-dolichol α-1,3-glucosyltransferase

Reaction:

dolichyl β-D-glucosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG6; Dol-P-Glc:Man₉GlcNAc₂-PP-Dol α-1,3-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-glucosyltransferase

Systematic name:

dolichyl β-D-glucosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-glucosyltransferase (configuration-inverting)

Comments:

The successive addition of three glucose residues by EC 2.4.1.267, EC 2.4.1.265 (Dol-P-Glc:Glc₁Man₉GlcNAc₂-PP-Dol α-1,3-glucosyltransferase) and EC 2.4.1.256 (Dol-P-Glc:Glc₂Man₉GlcNAc₂-PP-Dol α-1,2-glucosyltransferase) represents the final stage of the lipid-linked oligosaccharide assembly.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Reiss, G., te Heesen, S., Zimmerman, J., Robbins, P.W. and Aebi, M. Isolation of the ALG6 locus of Saccharomyces cerevisiae required for glucosylation in the N-linked glycosylation pathway. Glycobiology 6 (1996) 493–498. [DOI] [PMID: 8877369]
2.	Runge, K.W., Huffaker, T.C. and Robbins, P.W. Two yeast mutations in glucosylation steps of the asparagine glycosylation pathway. J. Biol. Chem. 259 (1984) 412–417. [PMID: 6423630]
3.	Westphal, V., Xiao, M., Kwok, P.Y. and Freeze, H.H. Identification of a frequent variant in ALG6, the cause of congenital disorder of glycosylation-Ic. Hum. Mutat. 22 (2003) 420–421. [DOI] [PMID: 14517965]

[EC 2.4.1.267 created 2011, modified 2012]

2.4.1.68

Relevance: 80.1%

Accepted name:

glycoprotein 6-α-L-fucosyltransferase

Reaction:

GDP-β-L-fucose + N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] = GDP + N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-[α-L-Fuc-(1→6)]-β-D-GlcNAc}-L-asparaginyl-[protein]

For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here

Other name(s):

GDP-fucose—glycoprotein fucosyltransferase; GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase; GDP-L-fucose-glycoprotein fucosyltransferase; glycoprotein fucosyltransferase; guanosine diphosphofucose-glycoprotein fucosyltransferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase; FucT; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N⁴-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase; GDP-β-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N⁴-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase

Systematic name:

GDP-β-L-fucose:N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 6-α-L-fucosyltransferase (configuration-inverting)

Comments:

This enzyme catalyses a reaction similar to that of EC 2.4.1.214, glycoprotein 3-α-L-fucosyltransferase, but transfers the L-fucosyl group from GDP-β-L-fucose to form an α1,6-linkage rather than an α1,3-linkage.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9033-08-3

References:

1.	Longmore, G.D. and Schachter, H. Product-identification and substrate-specificity studies of the GDP-L-fucose:2-acetamido-2-deoxy-β-D-glucoside (Fuc → Asn-linked GlcNAc) 6-α-L-fucosyltransferase in a Golgi-rich fraction from porcine liver. Carbohydr. Res. 100 (1982) 365–392. [DOI] [PMID: 7083256]
2.	Voynow, J.A., Scanlin, T.F. and Glick, M.C. A quantitative method for GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase activity with lectin affinity chromatography. Anal. Biochem. 168 (1988) 367–373. [DOI] [PMID: 3364733]
3.	Uozumi, N., Yanagidani, S., Miyoshi, E., Ihara, Y., Sakuma, T., Gao, C.-X., Teshima, T., Fujii, S., Shiba, T. and Taniguchi, N. Purification and cDNA cloning of porcine brain GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase. J. Biol. Chem. 271 (1996) 27810–27817. [DOI] [PMID: 8910378]

[EC 2.4.1.68 created 1972, modified 2002]

2.4.1.265

Relevance: 79.5%

Accepted name:

dolichyl-P-Glc:Glc₁Man₉GlcNAc₂-PP-dolichol α-1,3-glucosyltransferase

Reaction:

dolichyl β-D-glucosyl phosphate + α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG8; Dol-P-Glc:Glc₁Man₉GlcNAc₂-PP-Dol α-1,3-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Glc-α-(1→3)-D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-glucosyltransferase

Systematic name:

dolichyl β-D-glucosyl-phosphate:α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-glucosyltransferase (configuration-inverting)

Comments:

The successive addition of three glucose residues by EC 2.4.1.267 (dolichyl-P-Glc:Man₉GlcNAc₂-PP-dolichol α-1,3-glucosyltransferase), EC 2.4.1.265 and EC 2.4.1.256 (dolichyl-P-Glc:Glc₂Man₉GlcNAc₂-PP-dolichol α-1,2-glucosyltransferase) represents the final stage of the lipid-linked oligosaccharide assembly.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Stagljar, I., te Heesen, S. and Aebi, M. New phenotype of mutations deficient in glucosylation of the lipid-linked oligosaccharide: cloning of the ALG8 locus. Proc. Natl. Acad. Sci. USA 91 (1994) 5977–5981. [DOI] [PMID: 8016100]
2.	Runge, K.W. and Robbins, P.W. A new yeast mutation in the glucosylation steps of the asparagine-linked glycosylation pathway. Formation of a novel asparagine-linked oligosaccharide containing two glucose residues. J. Biol. Chem. 261 (1986) 15582–15590. [PMID: 3536907]
3.	Chantret, I., Dancourt, J., Dupre, T., Delenda, C., Bucher, S., Vuillaumier-Barrot, S., Ogier de Baulny, H., Peletan, C., Danos, O., Seta, N., Durand, G., Oriol, R., Codogno, P. and Moore, S.E. A deficiency in dolichyl-P-glucose:Glc₁Man₉GlcNAc₂-PP-dolichyl α3-glucosyltransferase defines a new subtype of congenital disorders of glycosylation. J. Biol. Chem. 278 (2003) 9962–9971. [DOI] [PMID: 12480927]

[EC 2.4.1.265 created 2011, modified 2012]

2.4.1.143

Relevance: 79.4%

Accepted name:

α-1,6-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here

Other name(s):

MGAT2 (gene name); N-acetylglucosaminyltransferase II; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase II; acetylglucosaminyltransferase II; uridine diphosphoacetylglucosamine-mannoside α1→6-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-1,6-mannosylglycoprotein β-1-2-N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-D-mannoside β1-2-acetylglucosaminyltransferase; UDP-GlcNAc:mannoside α1-6 acetylglucosaminyltransferase; α-1,6-mannosyl-glycoprotein β-1,2-N-acetylglucosaminyltransferase; GnTII; GlcNAc-T II; UDP-N-acetyl-D-glucosamine:6-(α-D-mannosyl)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:α-D-mannosyl-(1→6)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. Its activity initiates the synthesis of the second antenna of di-antennary complex N-glycans. While the natural substrate (produced by EC 3.2.1.114, mannosyl-oligosaccharide 1,3-1,6-α-mannosidase) is described here, the minimal substrate recognized by the enzyme is α-D-Man-(1→6)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→3)]-β-D-Man-R.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 105913-04-0

References:

1.	Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Bovine colostrum UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase I. Separation from UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase II, partial purification, and substrate specificity. J. Biol. Chem. 255 (1980) 4885–4893. [PMID: 6445358]
2.	Mendicino, J., Chandrasekaran, E.V., Anumula, K.R. and Davila, M. Isolation and properties of α-D-mannose:β-1,2-N-acetylglucosaminyltransferase from trachea mucosa. Biochemistry 20 (1981) 967–976. [PMID: 6452163]
3.	Oppenheimer, C.L., Eckhardt, A.E. and Hill, R.L. The nonidentity of porcine N-acetylglucosaminyltransferases I and II. J. Biol. Chem. 256 (1981) 11477–11482. [PMID: 6457827]
4.	Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
5.	Bendiak, B. and Schachter, H. Control of glycoprotein synthesis. Kinetic mechanism, substrate specificity, and inhibition characteristics of UDP-N-acetylglucosamine:α-D-mannoside β-1-2 N-acetylglucosaminyltransferase II from rat liver. J. Biol. Chem. 262 (1987) 5784–5790. [PMID: 2952645]
6.	Bendiak, B. and Schacter, H. Control of glycoprotein synthesis. Purification of UDP-N-acetylglucosamine:α-D-mannoside β1-2 N-acetylglucosaminyltransferase II from rat liver. J. Biol. Chem. 262 (1987) 5775–5783. [PMID: 2952644]
7.	Tan, J., D'Agostaro, A.F., Bendiak, B., Reck, F., Sarkar, M., Squire, J.A., Leong, P. and Schachter, H. The human UDP-N-acetylglucosamine: α-6-D-mannoside-β-1,2- N-acetylglucosaminyltransferase II gene (MGAT2). Cloning of genomic DNA, localization to chromosome 14q21, expression in insect cells and purification of the recombinant protein. Eur. J. Biochem. 231 (1995) 317–328. [DOI] [PMID: 7635144]

[EC 2.4.1.143 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]

2.4.1.214

Relevance: 79.1%

Accepted name:

glycoprotein 3-α-L-fucosyltransferase

Reaction:

For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here

Other name(s):

GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1,3-fucosyltransferase; GDP-L-Fuc:Asn-linked GlcNAc α1,3-fucosyltransferase; GDP-fucose:β-N-acetylglucosamine (Fuc to (Fucα1→6GlcNAc)-Asn-peptide) α1→3-fucosyltransferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N⁴-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase; GDP-β-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N⁴-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase

Systematic name:

GDP-β-L-fucose:N⁴-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 3-α-L-fucosyltransferase (configuration-retaining)

Comments:

Requires Mn²⁺. The enzyme transfers to N-linked oligosaccharide structures (N-glycans), generally with a specificity for N-glycans with one unsubstituted non-reducing terminal GlcNAc residue. This enzyme catalyses a reaction similar to that of EC 2.4.1.68, glycoprotein 6-α-L-fucosyltransferase, but transferring the L-fucosyl group from GDP-β-L-fucose to form an α1,3-linkage rather than an α1,6-linkage. The N-glycan products of this enzyme are present in plants, insects and some other invertebrates (e.g., Schistosoma, Haemonchus, Lymnaea).

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 68247-53-0

References:

1.	Wilson, I.B.H., Rendic, D., Freilinger, A., Dumic, J., Altmann, F., Mucha, J., Müller, S. and Hauser, M.-T. Cloning and expression of α1,3-fucosyltransferase homologues from Arabidopsis thaliana. Biochim. Biophys. Acta 1527 (2001) 88–96. [DOI] [PMID: 11420147]
2.	Fabini, G., Freilinger, A., Altmann, F. and Wilson, I.B.H. Identification of core α1,3-fucosylated glycans and cloning of the requisite fucosyltransferase cDNA from Drosophila melanogaster. Potential basis of the neural anti-horseradish peroxidase epitope. J. Biol. Chem. 276 (2001) 28058–28067. [DOI] [PMID: 11382750]
3.	Leiter, H., Mucha, J., Staudacher, E., Grimm, R., Glössl, J. and Altmann, F. Purification, cDNA cloning, and expression of GDP-L-Fuc:Asn-linked GlcNAc α1,3-fucosyltransferase from mung beans. J. Biol. Chem. 274 (1999) 21830–21839. [DOI] [PMID: 10419500]
4.	van Tetering, A., Schiphorst, W.E.C.M., van den Eijnden, D.H. and van Die, I. Characterization of core α1→3-fucosyltransferase from the snail Lymnaea stagnalis that is involved in the synthesis of complex type N-glycans. FEBS Lett. 461 (1999) 311–314. [DOI] [PMID: 10567717]
5.	Staudacher, E., Altmann, F., Glössl, J., März, L., Schachter, H., Kamerling, J.P., Haard, K. and Vliegenthart, J.F.G. GDP-fucose:β-N-acetylglucosamine (Fuc to (Fucα1→6GlcNAc)-Asn-peptide) α1→3-fucosyltransferase activity in honeybee (Apis mellifica) venom glands. The difucosylation of asparagine-bound N-acetylglucosamine. Eur. J. Biochem. 199 (1991) 745–751. [DOI] [PMID: 1868856]

[EC 2.4.1.214 created 2001]

2.4.1.260

Relevance: 78.5%

Accepted name:

dolichyl-P-Man:Man₇GlcNAc₂-PP-dolichol α-1,6-mannosyltransferase

Reaction:

dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-β-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-α-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG12; ALG12 mannosyltransferase; ALG12 α1,6mannosyltransferase; dolichyl-P-mannose:Man₇GlcNAc₂-PP-dolichyl mannosyltransferase; dolichyl-P-Man:Man₇GlcNAc₂-PP-dolichyl α6-mannosyltransferase; EBS4; Dol-P-Man:Man₇GlcNAc₂-PP-Dol α-1,6-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,6-mannosyltransferase

Systematic name:

dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-β-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 6-α-D-mannosyltransferase (configuration-inverting)

Comments:

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]
2.	Hong, Z., Jin, H., Fitchette, A.C., Xia, Y., Monk, A.M., Faye, L. and Li, J. Mutations of an α1,6 mannosyltransferase inhibit endoplasmic reticulum-associated degradation of defective brassinosteroid receptors in Arabidopsis. Plant Cell 21 (2009) 3792–3802. [DOI] [PMID: 20023196]
3.	Cipollo, J.F. and Trimble, R.B. The Saccharomyces cerevisiae alg12δ mutant reveals a role for the middle-arm α1,2Man- and upper-arm α1,2Manα1,6Man- residues of Glc₃Man₉GlcNAc₂-PP-Dol in regulating glycoprotein glycan processing in the endoplasmic reticulum and Golgi apparatus. Glycobiology 12 (2002) 749–762. [PMID: 12460943]
4.	Grubenmann, C.E., Frank, C.G., Kjaergaard, S., Berger, E.G., Aebi, M. and Hennet, T. ALG12 mannosyltransferase defect in congenital disorder of glycosylation type lg. Hum. Mol. Genet. 11 (2002) 2331–2339. [DOI] [PMID: 12217961]

[EC 2.4.1.260 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.160, modified 2012]

2.4.1.257

Relevance: 78.1%

Accepted name:

GDP-Man:Man₂GlcNAc₂-PP-dolichol α-1,6-mannosyltransferase

Reaction:

GDP-α-D-mannose + α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = GDP + α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

GDP-Man:Man₂GlcNAc₂-PP-Dol α-1,6-mannosyltransferase; Alg2 mannosyltransferase (ambiguous); ALG2 (gene name, ambiguous); GDP-Man:Man₁GlcNAc₂-PP-dolichol mannosyltransferase (ambiguous); GDP-D-mannose:D-Man-α-(1→3)-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-6-mannosyltransferase

Systematic name:

GDP-α-D-mannose:α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 6-α-D-mannosyltransferase (configuration-retaining)

Comments:

The biosynthesis of asparagine-linked glycoproteins utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. Alg2 mannosyltransferase from Saccharomyces cerevisiae carries out an α1,3-mannosylation (cf. EC 2.4.1.132) of β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol, followed by an α1,6-mannosylation, to form the first branched pentasaccharide intermediate of the dolichol pathway [1,2].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Kampf, M., Absmanner, B., Schwarz, M. and Lehle, L. Biochemical characterization and membrane topology of Alg2 from Saccharomyces cerevisiae as a bifunctional α1,3- and 1,6-mannosyltransferase involved in lipid-linked oligosaccharide biosynthesis. J. Biol. Chem. 284 (2009) 11900–11912. [DOI] [PMID: 19282279]
2.	O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]

[EC 2.4.1.257 created 2011, modified 2012]

2.4.1.256

Relevance: 76.9%

Accepted name:

dolichyl-P-Glc:Glc₂Man₉GlcNAc₂-PP-dolichol α-1,2-glucosyltransferase

Reaction:

dolichyl β-D-glucosyl phosphate + α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = dolichyl phosphate + α-D-Glc-(1→2)-α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG10; Dol-P-Glc:Glc₂Man₉GlcNAc₂-PP-Dol α-1,2-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Glc-α-(1→3)-D-Glc-α-(1→3)-D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-glucosyltransferase

Systematic name:

dolichyl β-D-glucosyl-phosphate:α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol α-1,2-glucosyltransferase (configuration-retaining)

Comments:

This eukaryotic enzyme performs the final step in the synthesis of the lipid-linked oligosaccharide, attaching D-glucose in an α-1,2-linkage to the outermost D-glucose in the long branch. The lipid-linked oligosaccharide is involved in N-linked protein glycosylation of selected asparagine residues of nascent polypeptide chains in eukaryotic cells.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Burda, P. and Aebi, M. The ALG10 locus of Saccharomyces cerevisiae encodes the α-1,2 glucosyltransferase of the endoplasmic reticulum: the terminal glucose of the lipid-linked oligosaccharide is required for efficient N-linked glycosylation. Glycobiology 8 (1998) 455–462. [DOI] [PMID: 9597543]

[EC 2.4.1.256 created 2011, modified 2012]

3.2.1.207

Relevance: 76.9%

Accepted name:

mannosyl-oligosaccharide α-1,3-glucosidase

Reaction:

(1) Glc₂Man₉GlcNAc₂-[protein] + H₂O = GlcMan₉GlcNAc₂-[protein] + β-D-glucopyranose
(2) GlcMan₉GlcNAc₂-[protein] + H₂O = Man₉GlcNAc₂-[protein] + β-D-glucopyranose

Glossary:

Glc₂Man₉GlcNAc₂-[protein] = {α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
GlcMan₉GlcNAc₂-[protein] = {α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
Man₉GlcNAc₂-[protein] = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]

Other name(s):

ER glucosidase II; α-glucosidase II; trimming glucosidase II; ROT2 (gene name); GTB1 (gene name); GANAB (gene name); PRKCSH (gene name)

Systematic name:

Glc₂Man₉GlcNAc₂-[protein] 3-α-glucohydrolase (configuration-inverting)

Comments:

This eukaryotic enzyme cleaves off sequentially the two α-1,3-linked glucose residues from the Glc₂Man₉GlcNAc₂ oligosaccharide precursor of immature N-glycosylated proteins.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Trombetta, E.S., Simons, J.F. and Helenius, A. Endoplasmic reticulum glucosidase II is composed of a catalytic subunit, conserved from yeast to mammals, and a tightly bound noncatalytic HDEL-containing subunit. J. Biol. Chem. 271 (1996) 27509–27516. [DOI] [PMID: 8910335]
2.	Ziak, M., Meier, M., Etter, K.S. and Roth, J. Two isoforms of trimming glucosidase II exist in mammalian tissues and cell lines but not in yeast and insect cells. Biochem. Biophys. Res. Commun. 280 (2001) 363–367. [DOI] [PMID: 11162524]
3.	Wilkinson, B.M., Purswani, J. and Stirling, C.J. Yeast GTB1 encodes a subunit of glucosidase II required for glycoprotein processing in the endoplasmic reticulum. J. Biol. Chem. 281 (2006) 6325–6333. [DOI] [PMID: 16373354]
4.	Mora-Montes, H.M., Bates, S., Netea, M.G., Diaz-Jimenez, D.F., Lopez-Romero, E., Zinker, S., Ponce-Noyola, P., Kullberg, B.J., Brown, A.J., Odds, F.C., Flores-Carreon, A. and Gow, N.A. Endoplasmic reticulum α-glycosidases of Candida albicans are required for N glycosylation, cell wall integrity, and normal host-fungus interaction. Eukaryot Cell 6 (2007) 2184–2193. [DOI] [PMID: 17933909]

[EC 3.2.1.207 created 2018]

2.4.1.258

Relevance: 74.5%

Accepted name:

dolichyl-P-Man:Man₅GlcNAc₂-PP-dolichol α-1,3-mannosyltransferase

Reaction:

dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

Man₅GlcNAc₂-PP-Dol mannosyltransferase; ALG3; dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase; Not56-like protein; Alg3 α-1,3-mannosyl transferase; Dol-P-Man:Man₅GlcNAc₂-PP-Dol α-1,3-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-mannosyltransferase

Systematic name:

dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-mannosyltransferase (configuration-inverting)

Comments:

The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc₃Man₉GlcNAc₂ core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man₅GlcNAc₂-PP-dolichol to Man₉Glc-NAc₂-PP-dolichol on the lumenal side use dolichyl β-D-mannosyl phosphate. The first step of this assembly pathway on the luminal side of the endoplasmic reticulum is catalysed by ALG3.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Sharma, C.B., Knauer, R. and Lehle, L. Biosynthesis of lipid-linked oligosaccharides in yeast: the ALG3 gene encodes the Dol-P-Man:Man₅GlcNAc₂-PP-Dol mannosyltransferase. Biol. Chem. 382 (2001) 321–328. [DOI] [PMID: 11308030]
2.	Cipollo, J.F. and Trimble, R.B. The accumulation of Man(6)GlcNAc(2)-PP-dolichol in the Saccharomyces cerevisiae Δalg9 mutant reveals a regulatory role for the Alg3p α1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing. J. Biol. Chem. 275 (2000) 4267–4277. [DOI] [PMID: 10660594]

[EC 2.4.1.258 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.258, modified 2012]

2.4.1.259

Relevance: 74.2%

Accepted name:

dolichyl-P-Man:Man₆GlcNAc₂-PP-dolichol α-1,2-mannosyltransferase

Reaction:

dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG9; ALG9 α1,2 mannosyltransferase; dolichylphosphomannose-dependent ALG9 mannosyltransferase; ALG9 mannosyltransferase; Dol-P-Man:Man₆GlcNAc₂-PP-Dol α-1,2-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→3)-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,2-mannosyltransferase

Systematic name:

dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-inverting)

Comments:

The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc₃Man₉GlcNAc₂ core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man₅GlcNAc₂-PP-Dol to Man₉Glc-NAc₂-PP-Dol on the lumenal side use dolichyl β-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different α-1,2-mannose residues - the addition of α-1,2-mannose to Man₆GlcNAc₂-PP-Dol (EC 2.4.1.259) and the addition of α-1,2-mannose to Man₈GlcNAc₂-PP-Dol (EC 2.4.1.261).

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Vleugels, W., Keldermans, L., Jaeken, J., Butters, T.D., Michalski, J.C., Matthijs, G. and Foulquier, F. Quality control of glycoproteins bearing truncated glycans in an ALG9-defective (CDG-IL) patient. Glycobiology 19 (2009) 910–917. [DOI] [PMID: 19451548]
2.	Cipollo, J.F. and Trimble, R.B. The accumulation of Man(6)GlcNAc(2)-PP-dolichol in the Saccharomyces cerevisiae Δalg9 mutant reveals a regulatory role for the Alg3p α1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing. J. Biol. Chem. 275 (2000) 4267–4277. [DOI] [PMID: 10660594]
3.	Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]

[EC 2.4.1.259 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.259, modified 2012]

2.4.1.261

Relevance: 74%

Accepted name:

dolichyl-P-Man:Man₈GlcNAc₂-PP-dolichol α-1,2-mannosyltransferase

Reaction:

dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG9; ALG9 α1,2 mannosyltransferase; dolichylphosphomannose-dependent ALG9 mannosyltransferase; ALG9 mannosyltransferase; Dol-P-Man:Man₈GlcNAc₂-PP-Dol α-1,2-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase

Systematic name:

dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-inverting)

Comments:

The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc₃Man₉GlcNAc₂ core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man₅GlcNAc₂-PP-Dol to Man₉Glc-NAc₂-PP-Dol on the lumenal side use dolichyl β-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different α-1,2-mannose residues: the addition of α-1,2-mannose to Man₆GlcNAc₂-PP-Dol (EC 2.4.1.259) and the addition of α-1,2-mannose to Man₈GlcNAc₂-PP-Dol (EC 2.4.1.261).

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Vleugels, W., Keldermans, L., Jaeken, J., Butters, T.D., Michalski, J.C., Matthijs, G. and Foulquier, F. Quality control of glycoproteins bearing truncated glycans in an ALG9-defective (CDG-IL) patient. Glycobiology 19 (2009) 910–917. [DOI] [PMID: 19451548]
2.	Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]

[EC 2.4.1.261 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.261, modified 2012]

2.4.2.61

Relevance: 73.4%

Accepted name:

α-dystroglycan β1,4-xylosyltransferase

Reaction:

UDP-α-D-xylose + 3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] = UDP + 3-O-[β-D-Xyl-(1→4)-Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein]

Other name(s):

TMEM5 (gene name)

Systematic name:

UDP-α-D-xylose:3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] xylosyltransferase

Comments:

This eukaryotic enzyme catalyses a step in the biosynthesis of the glycan moiety of the membrane protein α-dystroglycan. It is specific for the second ribitol 5-phosphate in the nascent glycan chain as acceptor.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

Vuillaumier-Barrot, S., Bouchet-Seraphin, C., Chelbi, M., Devisme, L., Quentin, S., Gazal, S., Laquerriere, A., Fallet-Bianco, C., Loget, P., Odent, S., Carles, D., Bazin, A., Aziza, J., Clemenson, A., Guimiot, F., Bonniere, M., Monnot, S., Bole-Feysot, C., Bernard, J.P., Loeuillet, L., Gonzales, M., Socha, K., Grandchamp, B., Attie-Bitach, T., Encha-Razavi, F. and Seta, N. Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly. Am. J. Hum. Genet. 91 (2012) 1135–1143. [PMID: 23217329]

Manya, H., Yamaguchi, Y., Kanagawa, M., Kobayashi, K., Tajiri, M., Akasaka-Manya, K., Kawakami, H., Mizuno, M., Wada, Y., Toda, T. and Endo, T. The muscular dystrophy gene TMEM5 encodes a ribitol β1,4-xylosyltransferase required for the functional glycosylation of dystroglycan. J. Biol. Chem. 291 (2016) 24618–24627. [PMID: 27733679]

[EC 2.4.2.61 created 2018]

2.4.1.101

Relevance: 72.8%

Accepted name:

α-1,3-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + Man₅GlcNAc₂-[protein] = UDP + Man₅GlcNAc₃-[protein]

For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here

Glossary:

Man₅GlcNAc₂-[protein] = α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-N-Asn-[protein]
Man₅GlcNAc₃-[protein]= β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-N-Asn-[protein]

Other name(s):

MGAT1 (gene name); N-acetylglucosaminyltransferase I; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase I; uridine diphosphoacetylglucosamine-α-1,3-mannosylglycoprotein β-1,2-N-acetylglucosaminyltransferase; UDP-N-acetylglucosaminyl:α-1,3-D-mannoside-β-1,2-N-acetylglucosaminyltransferase I; UDP-N-acetylglucosaminyl:α-3-D-mannoside β-1,2-N-acetylglucosaminyltransferase I; α-1,3-mannosyl-glycoprotein β-1,2-N-acetylglucosaminyltransferase; GnTI; GlcNAc-T I; UDP-N-acetyl-D-glucosamine:3-(α-D-mannosyl)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:α-D-mannosyl-(1→3)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. Its action is required before the other N-acetylglucosaminyltransferases involved in the process (GlcNAcT-II through VI) can act. While the natural substrate (produced by EC 3.2.1.113, mannosyl-oligosaccharide 1,2-α-mannosidase) is described here, the minimal substrate recognized by the enzyme is α-D-Man-(1→3)-β-D-Man-R.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 102576-81-8

References:

1.	Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Bovine colostrum UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase I. Separation from UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase II, partial purification, and substrate specificity. J. Biol. Chem. 255 (1980) 4885–4893. [PMID: 6445358]
2.	Mendicino, J., Chandrasekaran, E.V., Anumula, K.R. and Davila, M. Isolation and properties of α-D-mannose:β-1,2-N-acetylglucosaminyltransferase from trachea mucosa. Biochemistry 20 (1981) 967–976. [PMID: 6452163]
3.	Oppenheimer, C.L. and Hill, R.L. Purification and characterization of a rabbit liver α1→3 mannoside β1→2 N-acetylglucosaminyltransferase. J. Biol. Chem. 256 (1981) 799–804. [PMID: 6450208]
4.	Oppenheimer, C.L., Eckhardt, A.E. and Hill, R.L. The nonidentity of porcine N-acetylglucosaminyltransferases I and II. J. Biol. Chem. 256 (1981) 11477–11482. [PMID: 6457827]
5.	Miyagi, T. and Tsuiki, S. Studies on UDP-N-acetylglucosamine : α-mannoside β-N-acetylglucosaminyltransferase of rat liver and hepatomas. Biochim. Biophys. Acta 661 (1981) 148–157. [DOI] [PMID: 6170335]
6.	Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
7.	Vella, G.J., Paulsen, H. and Schachter, H. Control of glycoprotein synthesis. IX. A terminal Man alphal-3Man β1- sequence in the substrate is the minimum requirement for UDP-N-acetyl-D-glucosamine: α-D-mannoside (GlcNAc to Man α1-3) β2-N-acetylglucosaminyltransferase I. Can. J. Biochem. Cell Biol. 62 (1984) 409–417. [PMID: 6235906]
8.	Unligil, U.M., Zhou, S., Yuwaraj, S., Sarkar, M., Schachter, H. and Rini, J.M. X-ray crystal structure of rabbit N-acetylglucosaminyltransferase I: catalytic mechanism and a new protein superfamily. EMBO J. 19 (2000) 5269–5280. [DOI] [PMID: 11032794]

[EC 2.4.1.101 created 1983, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]

2.4.1.149

Relevance: 71.6%

Accepted name:

N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R = UDP + N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R

Other name(s):

uridine diphosphoacetylglucosamine-acetyllactosaminide β1→3-acetylglucosaminyltransferase; poly-N-acetyllactosamine extension enzyme; Galβ1→4GlcNAc-R β1→3 N-acetylglucosaminyltransferase; UDP-GlcNAc:GalR β-D-3-N-acetylglucosaminyltransferase; N-acetyllactosamine β(1-3)N-acetylglucosaminyltransferase; UDP-GlcNAc:Galβ1→4GlcNAcβ-Rβ1→3-N-acetylglucosaminyltransferase; GnTE; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-1,4-N-acetyl-D-glucosamine β-1,3-acetyl-D-glucosaminyltransferase; β-galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,3-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-D-glucosamine 3-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R 3-β N-acetylglucosaminyltransferase (configuration-inverting)

Comments:

Acts on β-galactosyl-1,4-N-acetylglucosaminyl termini on glycoproteins, glycolipids, and oligosaccharides.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 85638-39-7

References:

1.	Van den Eijnden, D.H., Winterwerp, H., Smeeman, P. and Schiphorst, W.E.C.M. Novikoff ascites tumor cells contain N-acetyllactosaminide β1→3 and β1→6 N-acetylglucosaminyltransferase activity. J. Biol. Chem. 258 (1983) 3435–3437. [PMID: 6219989]
2.	Basu, M. and Basu, S. Biosynthesis in vitro of Ii core glycosphingolipids from neolactotetraosylceramide by β 1-3- and β 1-6-N-acetylglucosaminyltransferases from mouse T-lymphoma. J. Biol. Chem. 259 (1984) 12557–12562. [PMID: 6238026]
3.	Takeya, A., Hosomi, O. and Kogure, T. The presence of N-acetyllactosamine and lactose: β (1-3)N-acetylglucosaminyltransferase activity in human urine. Jpn. J. Med. Sci. Biol. 38 (1985) 1–8. [PMID: 3160874]

[EC 2.4.1.149 created 1984 (EC 2.4.1.163 created 1989, incorporated 2016), modified 2016]

2.4.1.131

Relevance: 70.3%

Accepted name:

GDP-Man:Man₃GlcNAc₂-PP-dolichol α-1,2-mannosyltransferase

Reaction:

2 GDP-α-D-mannose + α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = 2 GDP + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol

For diagram of dolichyltetradecasaccharide biosynthesis, click here

Other name(s):

ALG11; ALG11 mannosyltransferase; LEW3 (gene name); At2G40190 (gene name); gmd3 (gene name); galactomannan deficiency protein 3; GDP-mannose:glycolipid 1,2-α-D-mannosyltransferase; glycolipid 2-α-mannosyltransferase; GDP-mannose:glycolipid 2-α-D-mannosyltransferase; GDP-Man:Man₃GlcNAc₂-PP-Dol α-1,2-mannosyltransferase; GDP-α-D-mannose:D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase

Systematic name:

GDP-α-D-mannose:α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-retaining)

Comments:

The biosynthesis of asparagine-linked glycoproteins (N-linked protein glycosylation) utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. ALG11 mannosyltransferase from Saccharomyces cerevisiae carries out two sequential steps in the formation of the lipid-linked core oligosaccharide, adding two mannose residues in α(1→2) linkages to the nascent oligosaccharide.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 74506-43-7

References:

1.	O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]
2.	Absmanner, B., Schmeiser, V., Kampf, M. and Lehle, L. Biochemical characterization, membrane association and identification of amino acids essential for the function of Alg11 from Saccharomyces cerevisiae, an α1,2-mannosyltransferase catalysing two sequential glycosylation steps in the formation of the lipid-linked core oligosaccharide. Biochem. J. 426 (2010) 205–217. [DOI] [PMID: 19929855]
3.	Schutzbach, J.S., Springfield, J.D. and Jensen, J.W. The biosynthesis of oligosaccharide-lipids. Formation of an α-1,2-mannosyl-mannose linkage. J. Biol. Chem. 255 (1980) 4170–4175. [PMID: 6154707]

[EC 2.4.1.131 created 1984, modified 2011, modified 2012]

3.2.1.114

Relevance: 69.5%

Accepted name:

mannosyl-oligosaccharide 1,3-1,6-α-mannosidase

Reaction:

Man₅GlcNAc₃-[protein] + 2 H₂O = Man₃GlcNAc₃-[protein] + 2 α-D-mannopyranose

For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here

Glossary:

Man₅GlcNAc₃-[protein] = [β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man₃GlcNAc₃-[protein] = {β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]

Other name(s):

MAN2A1 (gene name); MAN2A2 (gene name); mannosidase II; exo-1,3-1,6-α-mannosidase; α-D-mannosidase II; α-mannosidase II; α1-3,6-mannosidase; GlcNAc transferase I-dependent α1,3[α1,6]mannosidase; Golgi α-mannosidase II; ManII; 1,3(1,6)-α-D-mannosidase; 1,3-(1,6-)mannosyl-oligosaccharide α-D-mannohydrolase; (1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase

Systematic name:

(1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase (configuration-retaining)

Comments:

The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. It removes two mannosyl residues, one linked by α1,3 linkage, and the other linked by α1,6 linkage, both of which are removed by the same catalytic site. The enzyme is sensitive to swainsonine.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 82047-77-6

References:

1.	Tulsiani, D.R.P., Opheim, D.J. and Touster, O. Purification and characterization of α-D-mannosidase from rat liver golgi membranes. J. Biol. Chem. 252 (1977) 3227–3233. [PMID: 863880]
2.	Tabas, I. and Kornfeld, S. The synthesis of complex-type oligosaccharides. III. Identification of an α-D-mannosidase activity involved in a late stage of processing of complex-type oligosaccharides. J. Biol. Chem. 253 (1978) 7779–7786. [PMID: 212436]
3.	Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Processing of asparagine-linked oligosaccharides by one or more rat liver Golgi α-D-mannosidases dependent on the prior action of UDP-N-acetylglucosamine: α-D-mannoside β2-N-acetylglucosaminyltransferase I. J. Biol. Chem. 255 (1980) 4894–4902. [PMID: 6445359]
4.	Tulsiani, D.R.P., Hubbard, S.C., Robbins, P.W. and Touster, O. α-D-Mannosidases of rat liver Golgi membranes. Mannosidase II is the GlcNAcMAN₅-cleaving enzyme in glycoprotein biosynthesis and mannosidases IA and IB are the enzymes converting Man₉ precursors to Man₅ intermediates. J. Biol. Chem. 257 (1982) 3660–3668. [PMID: 7061502]
5.	Moremen, K.W. and Robbins, P.W. Isolation, characterization, and expression of cDNAs encoding murine α-mannosidase II, a Golgi enzyme that controls conversion of high mannose to complex N-glycans. J. Cell Biol. 115 (1991) 1521–1534. [PMID: 1757461]
6.	Misago, M., Liao, Y.F., Kudo, S., Eto, S., Mattei, M.G., Moremen, K.W. and Fukuda, M.N. Molecular cloning and expression of cDNAs encoding human α-mannosidase II and a previously unrecognized α-mannosidase IIx isozyme. Proc. Natl. Acad. Sci. USA 92 (1995) 11766–11770. [DOI] [PMID: 8524845]
7.	van den Elsen, J.M., Kuntz, D.A. and Rose, D.R. Structure of Golgi α-mannosidase II: a target for inhibition of growth and metastasis of cancer cells. EMBO J. 20 (2001) 3008–3017. [DOI] [PMID: 11406577]
8.	Athanasopoulos, V.I., Niranjan, K. and Rastall, R.A. The production, purification and characterisation of two novel α-D-mannosidases from Aspergillus phoenicis. Carbohydr. Res. 340 (2005) 609–617. [DOI] [PMID: 15721331]
9.	Shah, N., Kuntz, D.A. and Rose, D.R. Golgi α-mannosidase II cleaves two sugars sequentially in the same catalytic site. Proc. Natl. Acad. Sci. USA 105 (2008) 9570–9575. [DOI] [PMID: 18599462]
10.	Rose, D.R. Structure, mechanism and inhibition of Golgi α-mannosidase II. Curr. Opin. Struct. Biol. 22 (2012) 558–562. [DOI] [PMID: 22819743]

[EC 3.2.1.114 created 1986, modified 2018]

3.2.1.106

Relevance: 68.6%

Accepted name:

mannosyl-oligosaccharide glucosidase

Reaction:

Glc₃Man₉GlcNAc₂-[protein] + H₂O = Glc₂Man₉GlcNAc₂-[protein] + β-D-glucopyranose

Glossary:

Glc₃Man₉GlcNAc₂ = [α-D-Glc-(1→2)-α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Glc₂Man₉GlcNAc₂-[protein] = [α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]

Other name(s):

Glc3Man9NAc₂ oligosaccharide glucosidase; trimming glucosidase I; CWH41 (gene name); MOGS (gene name); mannosyl-oligosaccharide glucohydrolase

Systematic name:

Glc₃Man₉GlcNAc₂-[protein] glucohydrolase (configuration-inverting)

Comments:

This enzyme catalyses the first step in the processing of the N-glycan tetradecasaccharide precursor Glc₃Man₉GlcNAc₂, which takes place in the endoplasmic reticulum, by removing the distal α-1,2-linked glucose residue. This and subsequent processing steps are required before complex N-glycans can be synthesized.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 78413-07-7

References:

1.	Elting, J.J., Chen, W.W. and Lennarz, J. Characterization of a glucosidase involved in an initial step in the processing of oligosaccharide chains. J. Biol. Chem. 255 (1980) 2325–2331. [PMID: 7358674]
2.	Grinna, L.S. and Robbins, P.W. Glycoprotein biosynthesis. Rat liver microsomal glucosidases which process oligosaccharides. J. Biol. Chem. 254 (1979) 8814–8818. [PMID: 479161]
3.	Kilker, R.D., Saunier, B., Tkacz, J.S. and Herscovics, A. Partial purification from Saccharomyces cerevisiae of a soluble glucosidase which removes the terminal glucose from the oligosaccharide Glc₃Man₉GlcNAc₂. J. Biol. Chem. 256 (1981) 5299–5603. [PMID: 7014569]
4.	Grinna, L.S. and Robbins, P.W. Substrate specificities of rat liver microsomal glucosidases which process glycoproteins. J. Biol. Chem. 255 (1980) 2255–2258. [PMID: 7358666]
5.	Mark, M.J. and Kornfeld, S. Partial purification and characterization of the glucosidases involved in the processing of asparagine-linked oligosaccharides. Arch. Biochem. Biophys. 199 (1980) 249–258. [DOI] [PMID: 7356331]

[EC 3.2.1.106 created 1984, modified 2018]

2.4.1.223

Relevance: 68.5%

Accepted name:

glucuronosyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + [protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine = UDP + [protein]-3-O-(α-D-GlcNAc-(1→4)-β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine

For diagram of heparan biosynthesis (later stages), click here

Glossary:

[protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine = [protein]-3-O-(β-D-glucuronosyl-(1→3)-β-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-D-xylosyl)-L-serine

Other name(s):

α-N-acetylglucosaminyltransferase I; α1,4-N-acetylglucosaminyltransferase; glucuronosylgalactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-glucuronosyl-(1→3)-β-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-D-xylosyl-proteoglycan 4^IV-α-N-acetyl-D-glucosaminyltransferase; glucuronyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:[protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine 4^IV-α-N-acetyl-D-glucosaminyltransferase (configuration-retaining)

Comments:

Enzyme involved in the initiation of heparin and heparan sulfate synthesis, transferring GlcNAc to the (GlcA-Gal-Gal-Xyl-)Ser core. Apparently products of both the human EXTL2 and EXTL3 genes can catalyse this reaction. In Caenorhabditis elegans, the product of the rib-2 gene displays this activity as well as that of EC 2.4.1.224, glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-α-N-acetylglucosaminyltransferase. For explanation of the use of a superscript in the systematic name, see 2-Carb-37.2.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 179241-74-8

References:

1.	Kitagawa, H., Shimakawa, H. and Sugahara, K. The tumor suppressor EXT-like gene EXTL2 encodes an α1,4-N-acetylhexosaminyltransferase that transfers N-acetylgalactosamine and N-acetylglucosamine to the common glycosaminoglycan-protein linkage region. The key enzyme for the chain initiation of heparan sulfate. J. Biol. Chem. 274 (1999) 13933–13937. [DOI] [PMID: 10318803]
2.	Kitagawa, H., Egusa, N., Tamura, J.I., Kusche-Gullberg, M., Lindahl, U. and Sugahara, K. rib-2, a Caenorhabditis elegans homolog of the human tumor suppressor EXT genes encodes a novel α1,4-N-acetylglucosaminyltransferase involved in the biosynthetic initiation and elongation of heparan sulfate. J. Biol. Chem. 276 (2001) 4834–4838. [DOI] [PMID: 11121397]

[EC 2.4.1.223 created 2002, modified 2016]

3.2.1.165

Relevance: 68.4%

Accepted name:

exo-1,4-β-D-glucosaminidase

Reaction:

Hydrolysis of chitosan or chitosan oligosaccharides to remove successive D-glucosamine residues from the non-reducing termini

Glossary:

GlcN = D-glucosamine = 2-amino-2-deoxy-D-glucopyranose
GlcNAc = N-acetyl-D-glucosamine

Other name(s):

CsxA; GlcNase; exochitosanase; GlmA; exo-β-D-glucosaminidase; chitosan exo-1,4-β-D-glucosaminidase

Systematic name:

chitosan exo-(1→4)-β-D-glucosaminidase

Comments:

Chitosan is a partially or totally N-deacetylated chitin derivative that is found in the cell walls of some phytopathogenic fungi and comprises D-glucosamine residues with a variable content of GlcNAc residues [4]. Acts specifically on chitooligosaccharides and chitosan, having maximal activity on chitotetraose, chitopentaose and their corresponding alcohols [1]. The enzyme can degrade GlcN-GlcNAc but not GlcNAc-GlcNAc [3]. A member of the glycoside hydrolase family 2 (GH-2) [4].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Nanjo, F., Katsumi, R. and Sakai, K. Purification and characterization of an exo-β-D-glucosaminidase, a novel type of enzyme, from Nocardia orientalis. J. Biol. Chem. 265 (1990) 10088–10094. [PMID: 2351651]
2.	Nogawa, M., Takahashi, H., Kashiwagi, A., Ohshima, K., Okada, H. and Morikawa, Y. Purification and characterization of exo-β-D-glucosaminidase from a cellulolytic fungus, Trichoderma reesei PC-3-7. Appl. Environ. Microbiol. 64 (1998) 890–895. [PMID: 16349528]
3.	Fukamizo, T., Fleury, A., Côté, N., Mitsutomi, M. and Brzezinski, R. Exo-β-D-glucosaminidase from Amycolatopsis orientalis: catalytic residues, sugar recognition specificity, kinetics, and synergism. Glycobiology 16 (2006) 1064–1072. [DOI] [PMID: 16877749]
4.	Côté, N., Fleury, A., Dumont-Blanchette, E., Fukamizo, T., Mitsutomi, M. and Brzezinski, R. Two exo-β-D-glucosaminidases/exochitosanases from actinomycetes define a new subfamily within family 2 of glycoside hydrolases. Biochem. J. 394 (2006) 675–686. [DOI] [PMID: 16316314]
5.	Ike, M., Isami, K., Tanabe, Y., Nogawa, M., Ogasawara, W., Okada, H. and Morikawa, Y. Cloning and heterologous expression of the exo-β-D-glucosaminidase-encoding gene (gls93) from a filamentous fungus, Trichoderma reesei PC-3-7. Appl. Microbiol. Biotechnol. 72 (2006) 687–695. [DOI] [PMID: 16636831]

[EC 3.2.1.165 created 2008]

2.4.1.212

Relevance: 67.1%

Accepted name:

hyaluronan synthase

Reaction:

(1) UDP-N-acetyl-α-D-glucosamine + β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] = UDP + N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan]
(2) UDP-α-D-glucuronate + N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-[nascent hyaluronan] = UDP + β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-[nascent hyaluronan]

For diagram of reaction, click here

Glossary:

GlcA = glucuronic acid

Other name(s):

spHAS; seHAS; Alternating UDP-α-N-acetyl-D-glucosamine:β-D-glucuronosyl-(1→3)-[nascent hyaluronan] 4-N-acetyl-β-D-glucosaminyltransferase and UDP-α-D-glucuronate:N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] 3-β-D-glucuronosyltransferase

Systematic name:

Alternating UDP-N-acetyl-α-D-glucosamine:β-D-glucuronosyl-(1→3)-[nascent hyaluronan] 4-N-acetyl-β-D-glucosaminyltransferase and UDP-α-D-glucuronate:N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] 3-β-D-glucuronosyltransferase (configuration-inverting)

Comments:

The enzyme from Streptococcus Group A and Group C requires Mg²⁺. The enzyme adds GlcNAc to nascent hyaluronan when the non-reducing end is GlcA, but it adds GlcA when the non-reducing end is GlcNAc [3]. The enzyme is highly specific for UDP-GlcNAc and UDP-GlcA; no copolymerization is observed if either is replaced by UDP-Glc, UDP-Gal, UDP-GalNAc or UDP-GalA. Similar enzymes have been found in a variety of organisms.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 39346-43-5

References:

1.	DeAngelis, P.L., Papaconstantinou, J. and Weigel, P.H. Molecular cloning, identification and sequence of the hyaluronan synthase gene from Group A Streptococcus pyogenes. J. Biol. Chem. 268 (1993) 19181–19184. [PMID: 8366070]
2.	Jing, W. and DeAngelis, P.L. Dissection of the two transferase activities of the Pasteurella multocida hyaluronan synthase: two active sites exist in one polypeptide. Glycobiology 10 (2000) 883–889. [DOI] [PMID: 10988250]
3.	DeAngelis, P.L. Molecular directionality of polysaccharide polymerization by the Pasteurella multocida hyaluronan synthase. J. Biol. Chem. 274 (1999) 26557–26562. [DOI] [PMID: 10473619]
4.	Tlapak-Simmons, V.L., Baron, C.A. and Weigel, P.H. Characterization of the purified hyaluronan synthase from Streptococcus equisimilis. Biochemistry 43 (2004) 9234–9242. [DOI] [PMID: 15248781]

[EC 2.4.1.212 created 2001, modified 2007]

2.4.1.86

Relevance: 67%

Accepted name:

N-acetyl-β-D-glucosaminide β-(1,3)-galactosyltransferase

Reaction:

UDP-α-D-galactose + N-acetyl-β-D-glucosaminyl-R = UDP + β-D-galactosyl-(1→3)-N-acetyl-β-D-glucosaminyl-R

For diagram of lactotetraosylceramide biosynthesis, click here

Other name(s):

B3GALT1 (gene name); uridine diphosphogalactose-acetyl-glucosaminylgalactosylglucosylceramide galactosyltransferase; GalT-4; UDP-galactose:N-acetyl-D-glucosaminyl-1,3-D-galactosyl-1,4-D-glucosylceramide β-D-galactosyltransferase; UDP-galactose:N-acetyl-D-glucosaminyl-(1→3)-D-galactosyl-(1→4)-D-glucosylceramide 3-β-D-galactosyltransferase; UDP-galactose:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-β-D-glucosylceramide 3-β-D-galactosyltransferase; UDP-galactose:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-β-D-glucosyl(1↔1)ceramide 3-β-D-galactosyltransferase; UDP-galactose:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide 3-β-D-galactosyltransferase; glucosaminylgalactosylglucosylceramide β-galactosyltransferase; UDP-α-D-galactose:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide 3-β-D-galactosyltransferase

Systematic name:

UDP-α-D-galactose:N-acetyl-β-D-glucosaminyl-R 3-β-D-galactosyltransferase

Comments:

The enzyme transfers galactose from UDP-α-D-galactose to the 3-position of substrates with a non-reducing terminal N-acetyl-β-D-glucosamine (β-GlcNAc) residue. It can act on both glycolipids and glycoproteins, generating a structure known as the type 1 histo-blood group antigen precursor.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9073-46-5

References:

1.	Basu, M. and Basu, S. Enzymatic synthesis of a tetraglycosylceramide by a galactosyltransferase from rabbit bone marrow. J. Biol. Chem. 247 (1972) 1489–1495. [PMID: 4335001]
2.	Basu, M., Presper, K.A., Basu, S., Hoffman, L.M. and Brooks, S.E. Differential activities of glycolipid glycosyltransferases in Tay-Sachs disease: studies in cultured cells from cerebrum. Proc. Natl. Acad. Sci. USA 76 (1979) 4270–4274. [DOI] [PMID: 291963]
3.	Amado, M., Almeida, R., Carneiro, F., Levery, S.B., Holmes, E.H., Nomoto, M., Hollingsworth, M.A., Hassan, H., Schwientek, T., Nielsen, P.A., Bennett, E.P. and Clausen, H. A family of human β3-galactosyltransferases. Characterization of four members of a UDP-galactose:β-N-acetyl-glucosamine/β-nacetyl-galactosamine β-1,3-galactosyltransferase family. J. Biol. Chem. 273 (1998) 12770–12778. [DOI] [PMID: 9582303]
4.	Amado, M., Almeida, R., Schwientek, T. and Clausen, H. Identification and characterization of large galactosyltransferase gene families: galactosyltransferases for all functions. Biochim. Biophys. Acta 1473 (1999) 35–53. [DOI] [PMID: 10580128]
5.	Bardoni, A., Valli, M. and Trinchera, M. Differential expression of β1,3galactosyltransferases in human colon cells derived from adenocarcinomas or normal mucosa. FEBS Lett. 451 (1999) 75–80. [DOI] [PMID: 10356986]

[EC 2.4.1.86 created 1976, modified 2017]

2.4.1.255

Relevance: 66.7%

Accepted name:

protein O-GlcNAc transferase

Reaction:

(1) UDP-N-acetyl-α-D-glucosamine + [protein]-L-serine = UDP + [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine
(2) UDP-N-acetyl-α-D-glucosamine + [protein]-L-threonine = UDP + [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-threonine

Other name(s):

O-GlcNAc transferase; OGTase; O-linked N-acetylglucosaminyltransferase; uridine diphospho-N-acetylglucosamine:polypeptide β-N-acetylglucosaminyltransferase; protein O-linked β-N-acetylglucosamine transferase

Systematic name:

UDP-N-α-acetyl-D-glucosamine:[protein]-3-O-N-acetyl-β-D-glucosaminyl transferase

Comments:

Within higher eukaryotes post-translational modification of protein serines/threonines with N-acetylglucosamine (O-GlcNAc) is dynamic, inducible and abundant, regulating many cellular processes by interfering with protein phosphorylation. EC 2.4.1.255 (protein O-GlcNAc transferase) transfers GlcNAc onto substrate proteins and EC 3.2.1.169 (protein O-GlcNAcase) cleaves GlcNAc from the modified proteins.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Banerjee, S., Robbins, P.W. and Samuelson, J. Molecular characterization of nucleocytosolic O-GlcNAc transferases of Giardia lamblia and Cryptosporidium parvum. Glycobiology 19 (2009) 331–336. [DOI] [PMID: 18948359]
2.	Clarke, A.J., Hurtado-Guerrero, R., Pathak, S., Schuttelkopf, A.W., Borodkin, V., Shepherd, S.M., Ibrahim, A.F. and van Aalten, D.M. Structural insights into mechanism and specificity of O-GlcNAc transferase. EMBO J. 27 (2008) 2780–2788. [DOI] [PMID: 18818698]
3.	Rao, F.V., Dorfmueller, H.C., Villa, F., Allwood, M., Eggleston, I.M. and van Aalten, D.M. Structural insights into the mechanism and inhibition of eukaryotic O-GlcNAc hydrolysis. EMBO J. 25 (2006) 1569–1578. [DOI] [PMID: 16541109]
4.	Haltiwanger, R.S., Blomberg, M.A. and Hart, G.W. Glycosylation of nuclear and cytoplasmic proteins. Purification and characterization of a uridine diphospho-N-acetylglucosamine:polypeptide β-N-acetylglucosaminyltransferase. J. Biol. Chem. 267 (1992) 9005–9013. [PMID: 1533623]
5.	Lubas, W.A., Frank, D.W., Krause, M. and Hanover, J.A. O-Linked GlcNAc transferase is a conserved nucleocytoplasmic protein containing tetratricopeptide repeats. J. Biol. Chem. 272 (1997) 9316–9324. [DOI] [PMID: 9083068]
6.	Lazarus, M.B., Nam, Y., Jiang, J., Sliz, P. and Walker, S. Structure of human O-GlcNAc transferase and its complex with a peptide substrate. Nature 469 (2011) 564–567. [DOI] [PMID: 21240259]

[EC 2.4.1.255 created 2011]

2.4.1.304

Relevance: 65.3%

Accepted name:

UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,4-galactosyltransferase

Reaction:

UDP-α-D-galactose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Gal-(1→4)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol

Other name(s):

WfeD; UDP-Gal:GlcNAc-R 1,4-Gal-transferase; UDP-Gal:GlcNAc-pyrophosphate-lipid β-1,4-galactosyltransferase

Systematic name:

UDP-α-D-galactose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol β-1,4-galactosyltransferase

Comments:

The enzyme is involved in the the biosynthesis of the O-polysaccharide repeating unit of the bacterium Shigella boydii B14. The activity is stimulated by Mn²⁺ or to a lesser extent by Mg²⁺, Ca²⁺, Ni²⁺ or Pb²⁺.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

Xu, C., Liu, B., Hu, B., Han, Y., Feng, L., Allingham, J.S., Szarek, W.A., Wang, L. and Brockhausen, I. Biochemical characterization of UDP-Gal:GlcNAc-pyrophosphate-lipid β-1,4-Galactosyltransferase WfeD, a new enzyme from Shigella boydii type 14 that catalyzes the second step in O-antigen repeating-unit synthesis. J. Bacteriol. 193 (2011) 449–459. [DOI] [PMID: 21057010]

[EC 2.4.1.304 created 2013]

2.4.1.305

Relevance: 65.2%

Accepted name:

UDP-Glc:α-D-GlcNAc-glucosaminyl-diphosphoundecaprenol β-1,3-glucosyltransferase

Reaction:

UDP-α-D-glucose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Glc-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol

Other name(s):

WfaP; WfgD; UDP-Glc:GlcNAc-pyrophosphate-lipid β-1,3-glucosyltransferase; UDP-Glc:GlcNAc-diphosphate-lipid β-1,3-glucosyltransferase

Systematic name:

UDP-α-D-glucose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol β-1,3-glucosyltransferase

Comments:

The enzyme is involved in the the biosynthesis of the O-polysaccharide repeating unit of the bacterium Escherichia coli serotype O56 and serotype O152.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Brockhausen, I., Hu, B., Liu, B., Lau, K., Szarek, W.A., Wang, L. and Feng, L. Characterization of two β-1,3-glucosyltransferases from Escherichia coli serotypes O56 and O152. J. Bacteriol. 190 (2008) 4922–4932. [DOI] [PMID: 18487334]

[EC 2.4.1.305 created 2013]

3.2.1.149

Relevance: 64%

Accepted name:

β-primeverosidase

Reaction:

a 6-O-(β-D-xylopyranosyl)-β-D-glucopyranoside + H₂O = 6-O-(β-D-xylopyranosyl)-β-D-glucopyranose + an alcohol

Glossary:

primeverose = 6-O-(β-D-xylopyranosyl)-D-glucose
vicianose = 6-O-(α-L-arabinopyranosyl)-D-glucose

Systematic name:

6-O-(β-D-xylopyranosyl)-β-D-glucopyranoside 6-O-(β-D-xylosyl)-β-D-glucohydrolase

Comments:

The enzyme is responsible for the formation of the alcoholic aroma in oolong and black tea. In addition to β-primeverosides [i.e. 6-O-(β-D-xylopyranosyl)-β-D-glucopyranosides], it also hydrolyses 6-O-(β-D-apiofuranosyl)-β-D-glucopyranosides and, less rapidly, β-vicianosides and 6-O-(α-L-arabinofuranosyl)-β-D-glucopyranosides, but not β-glucosides. Geranyl-, linaloyl-, benzyl- and p-nitrophenol glycosides are all hydrolysed.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 884593-92-4

References:

1.	Ijima, Y., Ogawa, K., Watanabe, N., Usui, T., Ohnishi-Kameyama, M., Nagata, T. and Sakata, K. Characterization of β-primeverosidase, being concerned with alcoholic aroma formation in tea leaves to be processed into black tea, and preliminary observations on its substrate specificity. J. Agric. Food Chem. 46 (1998) 1712–1718.
2.	Ogawa, K., Ijima, Y., Guo, W., Watanabe, N., Usui, T., Dong, S., Tong, Q. and Sakata, K. Purification of a β-primeverosidase concerned with alcoholic aroma formation in tea leaves (cv. Shuxian) to be processed to oolong tea. J. Agric. Food Chem. 45 (1997) 877–882.

[EC 3.2.1.149 created 2001]

2.4.1.222

Relevance: 63.5%

Accepted name:

O-fucosylpeptide 3-β-N-acetylglucosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-glucosamine + [protein with EGF-like domain]-3-O-(α-L-fucosyl)-(L-serine/L-threonine) = UDP + [protein with EGF-like domain]-3-O-[N-acetyl-β-D-glucosaminyl-(1→3)-α-L-fucosyl]-(L-serine/L-threonine)

Glossary:

EGF = epidermal growth factor
EGF-like domain = an evolutionary conserved domain containing 30 to 40 amino-acid residues first described from epidermal growth factor

Other name(s):

O-fucosylpeptide β-1,3-N-acetylglucosaminyltransferase; fringe; UDP-D-GlcNAc:O-L-fucosylpeptide 3-β-N-acetyl-D-glucosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-glucosamine:[protein with EGF-like domain]-3-O-(α-L-fucosyl)-(L-serine/L-threonine) 3-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments:

The enzyme, found in animals and plants, is involved in the biosynthesis of the tetrasaccharides α-Neu5Ac-(2→3)-β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-α-L-Fuc and α-Neu5Ac-(2→6)-β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-α-L-Fuc, which are attached to L-Ser or L-Thr residues within the sequence Cys-Xaa-Xaa-Gly-Gly-Ser^/Thr-Cys in EGF-like domains in Notch and Factor-X proteins, respectively. The substrate is provided by EC 2.4.1.221, peptide-O-fucosyltransferase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 299203-70-6

References:

1.	Moloney, D.J., Panin, V.M., Johnston, S.H., Chen, J., Shao, L., Wilson, R., Wang, Y., Stanley, P., Irvine, K.D., Haltiwanger, R.S. and Vogt, T.F. Fringe is a glycosyltransferase that modifies Notch. Nature 406 (2000) 369–375. [DOI] [PMID: 10935626]
2.	Bruckner, K., Perez, L., Clausen, H. and Cohen, S. Glycosyltransferase activity of Fringe modulates Notch-Delta interactions. Nature 406 (2000) 411–415. [DOI] [PMID: 10935637]
3.	Rampal, R., Li, A.S., Moloney, D.J., Georgiou, S.A., Luther, K.B., Nita-Lazar, A. and Haltiwanger, R.S. Lunatic fringe, manic fringe, and radical fringe recognize similar specificity determinants in O-fucosylated epidermal growth factor-like repeats. J. Biol. Chem. 280 (2005) 42454–42463. [DOI] [PMID: 16221665]

[EC 2.4.1.222 created 2002, modified 2022]

3.2.1.130

Relevance: 63%

Accepted name:

glycoprotein endo-α-1,2-mannosidase

Reaction:

GlcMan₉GlcNAc₂-[protein] + H₂O = Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,2) + α-D-glucosyl-(1→3)-α-D-mannopyranose

Glossary:

GlcMan₉GlcNAc₂-[protein] = {α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,2) = {α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]

Other name(s):

glucosylmannosidase; endo-α-D-mannosidase; endo-α-mannosidase; endomannosidase; glucosyl mannosidase; MANEA (gene name); glycoprotein glucosylmannohydrolase

Systematic name:

glycoprotein glucosylmannohydrolase (configuration-retaining)

Comments:

The enzyme catalyses the hydrolysis of the terminal α-D-glucosyl-(1→3)-D-mannosyl unit from the GlcMan₉(GlcNAc)₂ oligosaccharide component of N-glucosylated proteins during their processing in the Golgi apparatus. The name for the isomer is based on a nomenclature proposed by Prien et al [7].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 108022-16-8

References:

1.	Lubas, W.A. and Spiro, R.G. Golgi endo-α-D-mannosidase from rat liver, a novel N-linked carbohydrate unit processing enzyme. J. Biol. Chem. 262 (1987) 3775–3781. [PMID: 3818665]
2.	Tulsiani, D.R.P., Coleman, V.P. and Touster, O. Asparagine-linked glycoprotein biosynthesis in rat brain: identification of glucosidase I, glucosidase II, and endomannosidase (glucosyl mannosidase). Arch. Biochem. Biophys. 277 (1990) 114–121. [DOI] [PMID: 2407194]
3.	Hiraizumi, S., Spohr, U. and Spiro, R.G. Ligand affinity chromatographic purification of rat liver Golgi endomannosidase. J. Biol. Chem. 269 (1994) 4697–4700. [PMID: 8106437]
4.	Spiro, M.J., Bhoyroo, V.D. and Spiro, R.G. Molecular cloning and expression of rat liver endo-α-mannosidase, an N-linked oligosaccharide processing enzyme. J. Biol. Chem. 272 (1997) 29356–29363. [DOI] [PMID: 9361017]
5.	Hamilton, S.R., Li, H., Wischnewski, H., Prasad, A., Kerley-Hamilton, J.S., Mitchell, T., Walling, A.J., Davidson, R.C., Wildt, S. and Gerngross, T.U. Intact α-1,2-endomannosidase is a typical type II membrane protein. Glycobiology 15 (2005) 615–624. [DOI] [PMID: 15677381]
6.	Hardt, B., Volker, C., Mundt, S., Salska-Navarro, M., Hauptmann, M. and Bause, E. Human endo-α1,2-mannosidase is a Golgi-resident type II membrane protein. Biochimie 87 (2005) 169–179. [DOI] [PMID: 15760709]
7.	Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]

[EC 3.2.1.130 created 1990, modified 2017]

3.2.1.96

Relevance: 62.8%

Accepted name:

mannosyl-glycoprotein endo-β-N-acetylglucosaminidase

Reaction:

Endohydrolysis of the N,N′-diacetylchitobiosyl unit in high-mannose glycopeptides and glycoproteins containing the -[Man(GlcNAc)₂]Asn- structure. One N-acetyl-D-glucosamine residue remains attached to the protein; the rest of the oligosaccharide is released intact

Other name(s):

N,N′-diacetylchitobiosyl β-N-acetylglucosaminidase; endo-β-N-acetylglucosaminidase; mannosyl-glycoprotein endo-β-N-acetylglucosamidase; di-N-acetylchitobiosyl β-N-acetylglucosaminidase; endo-β-acetylglucosaminidase; endo-β-(1→4)-N-acetylglucosaminidase; mannosyl-glycoprotein 1,4-N-acetamidodeoxy-β-D-glycohydrolase; endoglycosidase S; endo-N-acetyl-β-D-glucosaminidase; endo-N-acetyl-β-glucosaminidase; endo-β-N-acetylglucosaminidase D; endo-β-N-acetylglucosaminidase F; endo-β-N-acetylglucosaminidase H; endo-β-N-acetylglucosaminidase L; glycopeptide-D-mannosyl-4-N-(N-acetyl-D-glucosaminyl)₂-asparagine 1,4-N-acetyl-β-glucosaminohydrolase; endoglycosidase H

Systematic name:

glycopeptide-D-mannosyl-N⁴-(N-acetyl-D-glucosaminyl)₂-asparagine 1,4-N-acetyl-β-glucosaminohydrolase

Comments:

A group of related enzymes.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37278-88-9

References:

1.	Chien, S., Weinburg, R., Li, S. and Li, Y. Endo-β-N-acetylglucosaminidase from fig latex. Biochem. Biophys. Res. Commun. 76 (1977) 317–323. [DOI] [PMID: 1027432]
2.	Koide, N. and Muramatsu, T. Endo-β-N-acetylglucosaminidase acting on carbohydrate moieties of glycoproteins. Purification and properties of the enzyme from Diplococcus pneumoniae. J. Biol. Chem. 249 (1974) 4897–4904. [PMID: 4152561]
3.	Pierce, R.J., Spik, G. and Montreuil, J. Cytosolic location of an endo-N-acetyl-β-D-glucosaminidase activity in rat liver and kidney. Biochem. J. 180 (1979) 673. [PMID: 486141]
4.	Pierce, R.J., Spik, G. and Montreuil, J. Demonstration and cytosolic location of an endo-N-acetyl-β-D-glucosaminidase activity towards an asialo-N-acetyl-lactosaminic-type substrate in rat liver. Biochem. J. 185 (1980) 261–264. [PMID: 7378051]
5.	Tai, T., Yamashita, K., Ogata-Arakawa, M., Koide, N., Muramatsu, T., Iwashita, S., Inoue, Y. and Kobata, A. Structural studies of two ovalbumin glycopeptides in relation to the endo-β-N-acetylglucosaminidase specificity. J. Biol. Chem. 250 (1975) 8569–8575. [PMID: 389]
6.	Tarentino, A.L., Plummer, T.H., Jr. and Maley, F. The release of intact oligosaccharides from specific glycoproteins by endo-β-N-acetylglucosaminidase H. J. Biol. Chem. 249 (1974) 818–824. [PMID: 4204553]

[EC 3.2.1.96 created 1978]

3.2.1.21

Relevance: 62%

Accepted name:

β-glucosidase

Reaction:

Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose

Other name(s):

gentiobiase; cellobiase; emulsin; elaterase; aryl-β-glucosidase; β-D-glucosidase; β-glucoside glucohydrolase; arbutinase; amygdalinase; p-nitrophenyl β-glucosidase; primeverosidase; amygdalase; linamarase; salicilinase; β-1,6-glucosidase

Systematic name:

β-D-glucoside glucohydrolase

Comments:

Wide specificity for β-D-glucosides. Some examples also hydrolyse one or more of the following: β-D-galactosides, α-L-arabinosides, β-D-xylosides, β-D-fucosides.

Links to other databases:

BRENDA, EXPASY, GTD, KEGG, MetaCyc, PDB, CAS registry number: 9001-22-3

References:

1.	Chinchetru, M.A., Cabezas, J.A. and Calvo, P. Purification and characterization of a broad specificity β-glucosidase from sheep liver. Int. J. Biochem. 21 (1989) 469–476. [PMID: 2503402]
2.	Conchie, J. β-Glucosidase from rumen liquor. Preparation, assay and kinetics of action. Biochem. J. 58 (1954) 552–560. [PMID: 13230003]
3.	Dahlqvist, A. Pig intestinal β-glucosidase activities. I. Relation to β-galactosidase (lactase). Biochim. Biophys. Acta 50 (1961) 55–61. [DOI] [PMID: 13719334]
4.	Heyworth, R. and Walker, P.G. Almond-emulsin β-D-glucosidase and β-D-galactosidase. Biochem. J. 83 (1962) 331–335. [PMID: 13907157]
5.	Larner, J. Other glucosidases. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 4, Academic Press, New York, 1960, pp. 369–378.
6.	Sano, K., Amemura, A. and Harada, T. Purification and properties of a β-1,6-glucosidase from Flavobacterium. Biochim. Biophys. Acta 377 (1975) 410–420. [DOI] [PMID: 235305]

[EC 3.2.1.21 created 1961]

3.2.1.169

Relevance: 61.8%

Accepted name:

protein O-GlcNAcase

Reaction:

(1) [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine + H₂O = [protein]-L-serine + N-acetyl-D-glucosamine
(2) [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-theronine + H₂O = [protein]-L-threonine + N-acetyl-D-glucosamine

Other name(s):

OGA; glycoside hydrolase O-GlcNAcase; O-GlcNAcase; BtGH84; O-GlcNAc hydrolase

Systematic name:

[protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine/threonine N-acetylglucosaminyl hydrolase

Comments:

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Gao, Y., Wells, L., Comer, F.I., Parker, G.J. and Hart, G.W. Dynamic O-glycosylation of nuclear and cytosolic proteins: cloning and characterization of a neutral, cytosolic β-N-acetylglucosaminidase from human brain. J. Biol. Chem. 276 (2001) 9838–9845. [DOI] [PMID: 11148210]
2.	Wells, L., Gao, Y., Mahoney, J.A., Vosseller, K., Chen, C., Rosen, A. and Hart, G.W. Dynamic O-glycosylation of nuclear and cytosolic proteins: further characterization of the nucleocytoplasmic β-N-acetylglucosaminidase, O-GlcNAcase. J. Biol. Chem. 277 (2002) 1755–1761. [PMID: 11788610]
3.	Cetinbas, N., Macauley, M.S., Stubbs, K.A., Drapala, R. and Vocadlo, D.J. Identification of Asp¹⁷⁴ and Asp¹⁷⁵ as the key catalytic residues of human O-GlcNAcase by functional analysis of site-directed mutants. Biochemistry 45 (2006) 3835–3844. [DOI] [PMID: 16533067]
4.	Dennis, R.J., Taylor, E.J., Macauley, M.S., Stubbs, K.A., Turkenburg, J.P., Hart, S.J., Black, G.N., Vocadlo, D.J. and Davies, G.J. Structure and mechanism of a bacterial β-glucosaminidase having O-GlcNAcase activity. Nat. Struct. Mol. Biol. 13 (2006) 365–371. [DOI] [PMID: 16565725]
5.	Kim, E.J., Kang, D.O., Love, D.C. and Hanover, J.A. Enzymatic characterization of O-GlcNAcase isoforms using a fluorogenic GlcNAc substrate. Carbohydr. Res. 341 (2006) 971–982. [DOI] [PMID: 16584714]
6.	Dong, D.L. and Hart, G.W. Purification and characterization of an O-GlcNAc selective N-acetyl-β-D-glucosaminidase from rat spleen cytosol. J. Biol. Chem. 269 (1994) 19321–19330. [PMID: 8034696]

[EC 3.2.1.169 created 2011]

2.5.1.98

Relevance: 61.1%

Accepted name:

Rhizobium leguminosarum exopolysaccharide glucosyl ketal-pyruvate-transferase

Reaction:

phosphoenolpyruvate + [β-D-GlcA-(1→4)-2-O-Ac-β-D-GlcA-(1→4)-β-D-Glc-(1→4)-[3-O-(CH₃CH(OH)CH₂C(O))-4,6-CH₃(COO^-)C-β-D-Gal-(1→4)-β-D-Glc-(1→4)-β-D-Glc-(1→4)-β-D-Glc-(1→6)]-2(or 3)-O-Ac-α-D-Glc-(1→6)]_n = [β-D-GlcA-(1→4)-2-O-Ac-β-D-GlcA-(1→4)-β-D-Glc-(1→4)-[3-O-(CH₃CH(OH)CH₂C(O))-4,6-CH₃(COO^-)C-β-D-Gal-(1→3)-4,6-CH₃(COO^-)C-β-D-Glc-(1→4)-β-D-Glc-(1→4)-β-D-Glc-(1→6)]-2(or 3)-O-Ac-α-D-Glc-(1→6)]_n + phosphate

Other name(s):

PssM; phosphoenolpyruvate:[D-GlcA-β-(1→4)-2-O-Ac-D-GlcA-β-(1→4)-D-Glc-β-(1→4)-[3-O-CH₃-CH₂CH(OH)C(O)-D-Gal-β-(1→4)-D-Glc-β-(1→4)-D-Glc-β-(1→4)-D-Glc-β-(1→6)]-2(or 3)-O-Ac-D-Glc-α-(1→6)]_n 4,6-O-(1-carboxyethan-1,1-diyl)transferase

Systematic name:

phosphoenolpyruvate:[β-D-GlcA-(1→4)-2-O-Ac-β-D-GlcA-(1→4)-β-D-Glc-(1→4)-[3-O-CH₃-CH₂CH(OH)C(O)-4,6-CH₃(COO^-)C-β-D-Gal-(1→4)-β-D-Glc-(1→4)-β-D-Glc-(1→4)-β-D-Glc-(1→6)]-2(or 3)-O-Ac-α-D-Glc-(1→6)]_n 4,6-O-(1-carboxyethan-1,1-diyl)transferase

Comments:

The enzyme is responsible for pyruvylation of the subterminal glucose in the acidic octasaccharide repeating unit of the exopolysaccharide of Rhizobium leguminosarum (bv. viciae strain VF39) which is necessary to establish nitrogen-fixing symbiosis with Pisum sativum, Vicia faba, and Vicia sativa.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

Ivashina, T.V., Fedorova, E.E., Ashina, N.P., Kalinchuk, N.A., Druzhinina, T.N., Shashkov, A.S., Shibaev, V.N. and Ksenzenko, V.N. Mutation in the pssM gene encoding ketal pyruvate transferase leads to disruption of Rhizobium leguminosarum bv. viciae—Pisum sativum symbiosis. J. Appl. Microbiol. 109 (2010) 731–742. [DOI] [PMID: 20233262]

[EC 2.5.1.98 created 2012, modified 2018]

3.2.1.113

Relevance: 60.9%

Accepted name:

mannosyl-oligosaccharide 1,2-α-mannosidase

Reaction:

(1) Man₉GlcNAc₂-[protein] + 4 H₂O = Man₅GlcNAc₂-[protein] + 4 β-D-mannopyranose (overall reaction)
(1a) Man₉GlcNAc₂-[protein] + H₂O = Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,2) + β-D-mannopyranose
(1b) Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,2) + H₂O = Man₇GlcNAc₂-[protein] (isomer 7A_1,2,3B₂) + β-D-mannopyranose
(1c) Man₇GlcNAc₂-[protein] (isomer 7A_1,2,3B₂) + H₂O = Man₆GlcNAc₂-[protein] (isomer 6A_1,2B₂) + β-D-mannopyranose
(1d) Man₆GlcNAc₂-[protein] (isomer 6A_1,2B₂) + H₂O = Man₅GlcNAc₂-[protein] + β-D-mannopyranose
(2) Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,3) + 3 H₂O = Man₅GlcNAc₂-[protein] + 3 β-D-mannopyranose (overall reaction)
(2a) Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,3) + H₂O = Man₇GlcNAc₂-[protein] (isomer 7A_1,2,3B₁) + β-D-mannopyranose
(2b) Man₇GlcNAc₂-[protein] (isomer 7A_1,2,3B₁) + H₂O = Man₆GlcNAc₂-[protein] (isomer 6A_1,2,3) + β-D-mannopyranose
(2c) Man₆GlcNAc₂-[protein] (isomer 6A_1,2,3) + H₂O = Man₅GlcNAc₂-[protein] + β-D-mannopyranose

Glossary:

Man₉GlcNAc₂-[protein] = [α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man₈GlcNAc₂-[protein] (isomer 8A_1,2,3B_1,3) = [α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man₅GlcNAc₂-[protein] = [α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]

Other name(s):

mannosidase 1A; mannosidase 1B; 1,2-α-mannosidase; exo-α-1,2-mannanase; mannose-9 processing α-mannosidase; glycoprotein processing mannosidase I; mannosidase I; Man₉-mannosidase; ManI; 1,2-α-mannosyl-oligosaccharide α-D-mannohydrolase; MAN1A1 (gene name); MAN1A2 (gene name); MAN1C1 (gene name); 2-α-mannosyl-oligosaccharide α-D-mannohydrolase

Systematic name:

Man₉GlcNAc₂-[protein] α-2-mannohydrolase (configuration-inverting)

Comments:

This family of mammalian enzymes, located in the Golgi system, participates in the maturation process of N-glycans that leads to formation of hybrid and complex structures. The enzymes catalyse the hydrolysis of the four (1→2)-linked α-D-mannose residues from the Man₉GlcNAc₂ oligosaccharide attached to target proteins as described in reaction (1). Alternatively, the enzymes act on the Man₈GlcNAc₂ isomer formed by EC 3.2.1.209, endoplasmic reticulum Man₉GlcNAc₂ 1,2-α-mannosidase, as described in reaction (2). The enzymes are type II membrane proteins, require Ca²⁺, and use an inverting mechanism. While all three human enzymes can catalyse the reactions listed here, some of the enzymes can additionally catalyse hydrolysis in an alternative order, generating additional isomeric intermediates, although the final product is the same. The names of the isomers listed here are based on a nomenclature system proposed by Prien et al [7].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9068-25-1

References:

1.	Tabas, I. and Kornfeld, S. Purification and characterization of a rat liver Golgi α-mannosidase capable of processing asparagine-linked oligosaccharides. J. Biol. Chem. 254 (1979) 11655–11663. [PMID: 500665]
2.	Tulsiani, D.R.P., Hubbard, S.C., Robbins, P.W. and Touster, O. α-D-Mannosidases of rat liver Golgi membranes. Mannosidase II is the GlcNAcMAN₅-cleaving enzyme in glycoprotein biosynthesis and mannosidases IA and IB are the enzymes converting Man₉ precursors to Man₅ intermediates. J. Biol. Chem. 257 (1982) 3660–3668. [PMID: 7061502]
3.	Bieberich, E. and Bause, E. Man₉-mannosidase from human kidney is expressed in COS cells as a Golgi-resident type II transmembrane N-glycoprotein. Eur. J. Biochem. 233 (1995) 644–649. [PMID: 7588811]
4.	Tremblay, L.O., Campbell Dyke, N. and Herscovics, A. Molecular cloning, chromosomal mapping and tissue-specific expression of a novel human α1,2-mannosidase gene involved in N-glycan maturation. Glycobiology 8 (1998) 585–595. [PMID: 9592125]
5.	Lal, A., Pang, P., Kalelkar, S., Romero, P.A., Herscovics, A. and Moremen, K.W. Substrate specificities of recombinant murine Golgi α1,2-mannosidases IA and IB and comparison with endoplasmic reticulum and Golgi processing α1,2-mannosidases. Glycobiology 8 (1998) 981–995. [PMID: 9719679]
6.	Tremblay, L.O. and Herscovics, A. Characterization of a cDNA encoding a novel human Golgi α 1, 2-mannosidase (IC) involved in N-glycan biosynthesis. J. Biol. Chem. 275 (2000) 31655–31660. [PMID: 10915796]
7.	Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]

[EC 3.2.1.113 created 1986, modified 2019]

3.2.1.6

Relevance: 60.5%

Accepted name:

endo-1,3(4)-β-glucanase

Reaction:

Endohydrolysis of (1→3)- or (1→4)-linkages in β-D-glucans when the glucose residue whose reducing group is involved in the linkage to be hydrolysed is itself substituted at C-3

Other name(s):

endo-1,3-β-D-glucanase; laminarinase; laminaranase; β-1,3-glucanase; β-1,3-1,4-glucanase; endo-1,3-β-glucanase; endo-β-1,3(4)-glucanase; endo-β-1,3-1,4-glucanase; endo-β-(1→3)-D-glucanase; endo-1,3-1,4-β-D-glucanase; endo-β-(1-3)-D-glucanase; endo-β-1,3-glucanase IV; endo-1,3-β-D-glucanase; 1,3-(1,3;1,4)-β-D-glucan 3(4)-glucanohydrolase

Systematic name:

3(or 4)-β-D-glucan 3(4)-glucanohydrolase

Comments:

Substrates include laminarin, lichenin and cereal D-glucans; different from EC 3.2.1.52 β-N-acetylhexosaminidase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 62213-14-3

References:

1.	Barras, D.R. and Stone, B.A. β-1,3-Glucan hydrolases from Euglena gracilis. I. The nature of the hydrolases. Biochim. Biophys. Acta 191 (1969) 329–341. [DOI] [PMID: 5354264]
2.	Barras, D.R. and Stone, B.A. β-1,3-Glucan hydrolases from Euglena gracilis. II. Purification and properties of the β-1,3-glucan exo-hydrolase. Biochim. Biophys. Acta 191 (1969) 342–353. [DOI] [PMID: 5354265]
3.	Cunningham, L.W. and Manners, D.J. Enzymic degradation of lichenin. Biochem. J. 80 (1961) 42.
4.	Reese, E.T. and Mandels, M. β-D-1,3-Glucanases in fungi. Can. J. Microbiol. 5 (1959) 173–185. [PMID: 13638895]
5.	Sova, V.V., Elyakova, L.A. and Vaskovsky, V.E. Purification and some properties of β-1,3-glucan glucanohydrolase from the crystalline style of bivalvia, Spisula sachalinensis. Biochim. Biophys. Acta 212 (1970) 111–115. [DOI] [PMID: 5500926]

[EC 3.2.1.6 created 1961, modified 1976]

3.1.1.103

Relevance: 60.4%

Accepted name:

teichoic acid D-alanine hydrolase

Reaction:

[(4-D-Ala)-(2-GlcNAc)-Rib-ol-P]_n-[Gro-P]_m-β-D-ManNAc-(1→4)-α-D-GlcNAc-P-peptidoglycan + n H₂O = [(2-GlcNAc)-Rib-ol-P]_n-[Gro-P]_m-β-D-ManNAc-(1→4)-α-D-GlcNAc-P-peptidoglycan + n D-alanine

Glossary:

Rib-ol = ribitol

Other name(s):

fmtA (gene name)

Systematic name:

teichoic acid D-alanylhydrolase

Comments:

The enzyme, characterized from the bacterium Staphylococcus aureus, removes D-alanine groups from the teichoic acid produced by this organism, thus modulating the electrical charge of the bacterial surface. The activity greatly increases methicillin resistance in MRSA strains.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Komatsuzawa, H., Sugai, M., Ohta, K., Fujiwara, T., Nakashima, S., Suzuki, J., Lee, C.Y. and Suginaka, H. Cloning and characterization of the fmt gene which affects the methicillin resistance level and autolysis in the presence of triton X-100 in methicillin-resistant Staphylococcus aureus. Antimicrob. Agents Chemother. 41 (1997) 2355–2361. [PMID: 9371333]
2.	Qamar, A. and Golemi-Kotra, D. Dual roles of FmtA in Staphylococcus aureus cell wall biosynthesis and autolysis. Antimicrob. Agents Chemother. 56 (2012) 3797–3805. [DOI] [PMID: 22564846]
3.	Rahman, M.M., Hunter, H.N., Prova, S., Verma, V., Qamar, A. and Golemi-Kotra, D. The Staphylococcus aureus methicillin resistance factor FmtA is a D-amino esterase that acts on teichoic acids. MBio 7 (2016) e02070. [DOI] [PMID: 26861022]

[EC 3.1.1.103 created 2018]

2.4.1.244

Relevance: 60%

Accepted name:

N-acetyl-β-glucosaminyl-glycoprotein 4-β-N-acetylgalactosaminyltransferase

Reaction:

UDP-N-acetyl-α-D-galactosamine + N-acetyl-β-D-glucosaminyl group = UDP + N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl group

Glossary:

N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-β-D-glucosamine = N,N′-diacetyllactosediamine

Other name(s):

β1,4-N-acetylgalactosaminyltransferase III; β4GalNAc-T3; β1,4-N-acetylgalactosaminyltransferase IV; β4GalNAc-T4; UDP-N-acetyl-D-galactosamine:N-acetyl-D-glucosaminyl-group β-1,4-N-acetylgalactosaminyltransferase; UDP-N-acetyl-D-galactosamine:N-acetyl-β-D-glucosaminyl-group 4-β-N-acetylgalactosaminyltransferase

Systematic name:

UDP-N-acetyl-α-D-galactosamine:N-acetyl-β-D-glucosaminyl-group 4-β-N-acetylgalactosaminyltransferase

Comments:

The enzyme from human can transfer N-acetyl-D-galactosamine (GalNAc) to N-glycan and O-glycan substrates that have N-acetyl-D-glucosamine (GlcNAc) but not D-glucuronic acid (GlcUA) at their non-reducing end. The N-acetyl-β-D-glucosaminyl group is normally on a core oligosaccharide although benzyl glycosides have been used in enzyme-characterization experiments. Some glycohormones, e.g. lutropin and thyrotropin contain the N-glycan structure containing the N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl group.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

Sato, T., Gotoh, M., Kiyohara, K., Kameyama, A., Kubota, T., Kikuchi, N., Ishizuka, Y., Iwasaki, H., Togayachi, A., Kudo, T., Ohkura, T., Nakanishi, H. and Narimatsu, H. Molecular cloning and characterization of a novel human β1,4-N-acetylgalactosaminyltransferase, β4GalNAc-T3, responsible for the synthesis of N,N'-diacetyllactosediamine, GalNAc β1-4GlcNAc. J. Biol. Chem. 278 (2003) 47534–47544. [DOI] [PMID: 12966086]

Gotoh, M., Sato, T., Kiyohara, K., Kameyama, A., Kikuchi, N., Kwon, Y.D., Ishizuka, Y., Iwai, T., Nakanishi, H. and Narimatsu, H. Molecular cloning and characterization of β1,4-N-acetylgalactosaminyltransferases IV synthesizing N,N'-diacetyllactosediamine. FEBS Lett. 562 (2004) 134–140. [DOI] [PMID: 15044014]

[EC 2.4.1.244 created 2006]

3.2.1.187

Relevance: 59.8%

Accepted name:

(Ara-f)₃-Hyp β-L-arabinobiosidase

Reaction:

4-O-(β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl)-(2S,4S)-4-hydroxyproline + H₂O = 4-O-(β-L-arabinofuranosyl)-(2S,4S)-4-hydroxyproline + β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranose

Glossary:

4-O-(β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl)-(2S,4S)-4-hydroxyproline = (Ara-f)₃-Hyp

Other name(s):

hypBA2 (gene name); β-L-arabinobiosidase

Systematic name:

4-O-(β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranosyl)-(2S,4S)-4-hydroxyproline β-L-arabinofuranosyl-(1→2)-β-L-arabinofuranose hydrolase

Comments:

The enzyme, which was identified in the bacterium Bifidobacterium longum JCM1217, is specific for (Ara-f)₃-Hyp, a sugar chain found in hydroxyproline-rich glyoproteins such as extensin and lectin. The enzyme was not able to accept (Ara-f)₂-Hyp or (Ara-f)₄-Hyp as substrates. In the presence of 1-alkanols, the enzyme demonstrates transglycosylation activity, retaining the anomeric configuration of the arabinofuranose residue.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Fujita, K., Sakamoto, S., Ono, Y., Wakao, M., Suda, Y., Kitahara, K. and Suganuma, T. Molecular cloning and characterization of a β-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family. J. Biol. Chem. 286 (2011) 5143–5150. [DOI] [PMID: 21149454]

[EC 3.2.1.187 created 2013]

2.4.1.303

Relevance: 59.8%

Accepted name:

UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,3-galactosyltransferase

Reaction:

UDP-α-D-galactose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Gal-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol

Other name(s):

WbbD; WbbD β3Gal-transferase; UDP-Gal:GlcNAc-R β1,3-galactosyltransferase; UDP-Gal:GlcNAcα-pyrophosphate-R β1,3-galactosyltransferase; UDP-Gal:GlcNAc-R galactosyltransferase

Systematic name:

UDP-α-D-galactose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 3-β-galactosyltransferase (configuration-inverting)

Comments:

The enzyme is involved in the the biosynthesis of the O-antigen repeating unit of Escherichia coli O7:K1 (VW187). Requires Mn²⁺. cf. EC 2.4.1.343, UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol α-1,3-galactosyltransferase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Riley, J.G., Menggad, M., Montoya-Peleaz, P.J., Szarek, W.A., Marolda, C.L., Valvano, M.A., Schutzbach, J.S. and Brockhausen, I. The wbbD gene of E. coli strain VW187 (O7:K1) encodes a UDP-Gal: GlcNAcα-pyrophosphate-R β1,3-galactosyltransferase involved in the biosynthesis of O7-specific lipopolysaccharide. Glycobiology 15 (2005) 605–613. [DOI] [PMID: 15625181]
2.	Brockhausen, I., Riley, J.G., Joynt, M., Yang, X. and Szarek, W.A. Acceptor substrate specificity of UDP-Gal: GlcNAc-R β1,3-galactosyltransferase (WbbD) from Escherichia coli O7:K1. Glycoconj. J. 25 (2008) 663–673. [DOI] [PMID: 18536883]

[EC 2.4.1.303 created 2013, modified 2017]

3.2.1.52

Relevance: 59.6%

Accepted name:

β-N-acetylhexosaminidase

Reaction:

Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-β-D-hexosaminides

Other name(s):

hexosaminidase; β-acetylaminodeoxyhexosidase; N-acetyl-β-D-hexosaminidase; N-acetyl-β-hexosaminidase; β-hexosaminidase; β-acetylhexosaminidinase; β-D-N-acetylhexosaminidase; β-N-acetyl-D-hexosaminidase; β-N-acetylglucosaminidase; hexosaminidase A; N-acetylhexosaminidase; β-D-hexosaminidase; NAHase

Systematic name:

β-N-acetyl-D-hexosaminide N-acetylhexosaminohydrolase

Comments:

Acts on N-acetylglucosides and N-acetylgalactosides.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9012-33-3

References:

1.	Cabezas, J.A. Some comments on the type references of the official nomenclature (IUB) for β-N-acetylglucosaminidase, β-N-acetylhexosaminidase and β-N-acetylgalactosaminidase. Biochem. J. 261 (1989) 1059–1060. [PMID: 2529847]
2.	Calvo, P., Reglero, A. and Cabezas, J.A. Purification and properties of β-N-acetylhexosaminidase from the mollusc Helicella ericetorum Muller. Biochem. J. 175 (1978) 743–750. [PMID: 33660]
3.	Frohwein, Y.S. and Gatt, S. Isolation of β-N-acetylhexosaminidase, β-N-acetylglucosaminidase, and β-N-acetylgalactosaminidase from calf brain. Biochemistry 6 (1967) 2775–2782. [PMID: 6055190]
4.	Li, S.-C. and Li, Y.-T. Studies on the glycosidases of jack bean meal. 3. Crystallization and properties of β-N-acetylhexosaminidase. J. Biol. Chem. 245 (1970) 5153–5160. [PMID: 5506280]

[EC 3.2.1.52 created 1972 (EC 3.2.1.30 created 1961, incorporated 1992 [EC 3.2.1.29 created 1961, incorporated 1972])]