The Enzyme Database

Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB)

Proposed Changes to the Enzyme List

The entries below are proposed additions and amendments to the Enzyme Nomenclature list. They were prepared for the NC-IUBMB by Kristian Axelsen, Ron Caspi, Ture Damhus, Shinya Fushinobu, Julia Hauenstein, Antje Jäde, Masaaki Kotera, Andrew McDonald, Gerry Moss, Ida Schomburg and Keith Tipton. Comments and suggestions on these draft entries should be sent to Dr Andrew McDonald (Department of Biochemistry, Trinity College Dublin, Dublin 2, Ireland). The date on which an enzyme will be made official is appended after the EC number. To prevent confusion please do not quote new EC numbers until they are incorporated into the main list.

An asterisk before 'EC' indicates that this is an amendment to an existing enzyme rather than a new enzyme entry.


Contents

*EC 1.1.1.376 L-arabinose 1-dehydrogenase [NAD(P)+]
EC 1.1.1.427 D-arabinose 1-dehydrogenase (NADP+)
EC 1.1.1.428 4-methylthio 2-oxobutanoate reductase (NADH)
EC 1.1.1.429 (2S)-[(R)-hydroxy(phenyl)methyl]succinyl-CoA dehydrogenase
*EC 1.1.3.29 N-acylhexosamine oxidase
EC 1.3.3.17 benzylmalonyl-CoA dehydrogenase
EC 1.3.99.41 3-(methylsulfanyl)propanoyl-CoA 2-dehydrogenase
*EC 1.5.3.1 sarcosine oxidase (formaldehyde-forming)
EC 1.5.3.24 sarcosine oxidase (5,10-methylenetetrahydrofolate-forming)
*EC 1.5.8.3 sarcosine dehydrogenase
*EC 1.14.14.147 22α-hydroxysteroid 23-monooxygenase
EC 1.14.14.178 steroid 22S-hydroxylase
EC 1.14.19.79 3β,22α-dihydroxysteroid 3-dehydrogenase
EC 2.3.1.308 tubulin N-terminal N-acetyltransferase NAT9
EC 2.4.1.387 isomaltosyltransferase
EC 2.4.1.388 glucosylgalactose phosphorylase
EC 2.4 Glycosyltransferases
EC 2.4.3 Sialyltransferases
EC 2.4.3.1 β-galactoside α-(2,6)-sialyltransferase
EC 2.4.3.2 β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase
EC 2.4.3.3 α-N-acetylgalactosaminide α-2,6-sialyltransferase
EC 2.4.3.4 β-galactoside α-2,3-sialyltransferase
EC 2.4.3.5 galactosyldiacylglycerol α-2,3-sialyltransferase
EC 2.4.3.6 N-acetyllactosaminide α-2,3-sialyltransferase
EC 2.4.3.7 α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylgalactosaminide 6-α-sialyltransferase
EC 2.4.3.8 α-N-acetylneuraminate α-2,8-sialyltransferase
EC 2.4.3.9 lactosylceramide α-2,3-sialyltransferase
EC 2.4.3.10 N-acetylglucosaminide α-(2,6)-sialyltransferase
EC 2.4.99.1 transferred
EC 2.4.99.2 transferred
EC 2.4.99.3 transferred
EC 2.4.99.4 transferred
EC 2.4.99.5 transferred
EC 2.4.99.6 transferred
EC 2.4.99.7 transferred
EC 2.4.99.8 transferred
EC 2.4.99.9 transferred
EC 2.4.99.10 transferred
EC 2.4.99.22 transferred
*EC 2.6.1.85 aminodeoxychorismate synthase
EC 2.7.1.236 NAD+ 3′-kinase
*EC 2.7.8.7 holo-[acyl-carrier-protein] synthase
*EC 2.8.3.18 succinyl-CoA:acetate CoA-transferase
EC 2.8.3.27 propanoyl-CoA:succinate CoA transferase
EC 2.8.3.28 phenylsuccinyl-CoA transferase
EC 3.1.1.119 transferred
*EC 3.2.1.62 glycosylceramidase
*EC 3.2.1.108 lactase
EC 3.2.1.216 kojibiose hydrolase
EC 3.2.1.217 exo-acting protein-α-N-acetylgalactosaminidase
*EC 3.5.4.25 GTP cyclohydrolase II
EC 4.2.1.180 (E)-benzylidenesuccinyl-CoA hydratase
*EC 5.3.1.4 L-arabinose isomerase
*EC 5.3.1.5 xylose isomerase
EC 6.2.1.75 indoleacetate—CoA ligase


*EC 1.1.1.376
Accepted name: L-arabinose 1-dehydrogenase [NAD(P)+]
Reaction: α-L-arabinopyranose + NAD(P)+ = L-arabinono-1,4-lactone + NAD(P)H + H+
For diagram of L-Arabinose catabolism, click here
Other name(s): L-arabino-aldose dehydrogenase
Systematic name: α-L-arabinopyranose:NAD(P)+ 1-oxidoreductase
Comments: The enzymes from the bacterium Azospirillum brasilense and the archaeon Haloferax volcanii are part of the L-arabinose degradation pathway and prefer NADP+ over NAD+. In vitro the enzyme from Azospirillum brasilense shows also high catalytic efficiency with D-galactose. The enzyme is specific for α-L-arabinopyranose [3,4].
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Novick, N.J. and Tyler, M.E. Partial purification and properties of an L-arabinose dehydrogenase from Azospirillum brasilense. Can. J. Microbiol. 29 (1983) 242–246.
2.  Watanabe, S., Kodaki, T. and Makino, K. Cloning, expression, and characterization of bacterial L-arabinose 1-dehydrogenase involved in an alternative pathway of L-arabinose metabolism. J. Biol. Chem. 281 (2006) 2612–2623. [DOI] [PMID: 16326697]
3.  Johnsen, U., Sutter, J.M., Zaiss, H. and Schonheit, P. L-Arabinose degradation pathway in the haloarchaeon Haloferax volcanii involves a novel type of L-arabinose dehydrogenase. Extremophiles 17 (2013) 897–909. [DOI] [PMID: 23949136]
4.  Aro-Karkkainen, N., Toivari, M., Maaheimo, H., Ylilauri, M., Pentikainen, O.T., Andberg, M., Oja, M., Penttila, M., Wiebe, M.G., Ruohonen, L. and Koivula, A. L-arabinose/D-galactose 1-dehydrogenase of Rhizobium leguminosarum bv. trifolii characterised and applied for bioconversion of L-arabinose to L-arabonate with Saccharomyces cerevisiae. Appl. Microbiol. Biotechnol. 98 (2014) 9653–9665. [DOI] [PMID: 25236800]
[EC 1.1.1.376 created 2014, modified 2022]
 
 
EC 1.1.1.427
Accepted name: D-arabinose 1-dehydrogenase (NADP+)
Reaction: D-arabinofuranose + NADP+ = D-arabinono-1,4-lactone + NADPH + H+
Other name(s): AraDH; adh-4 (gene name)
Systematic name: D-arabinose:NADP+ 1-oxidoreductase
Comments: The enzyme from the archaeon Saccharolobus solfataricus is tetrameric and contains zinc. L-fucose also is a substrate. In contrast to EC 1.1.1.116 (D-arabinose 1-dehydrogenase (NAD+)) and EC 1.1.1.117 (D-arabinose 1-dehydrogenase [NAD(P)+]), this enzyme is specific for NADP+.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Brouns, S.J., Walther, J., Snijders, A.P., van de Werken, H.J., Willemen, H.L., Worm, P., de Vos, M.G., Andersson, A., Lundgren, M., Mazon, H.F., van den Heuvel, R.H., Nilsson, P., Salmon, L., de Vos, W.M., Wright, P.C., Bernander, R. and van der Oost, J. Identification of the missing links in prokaryotic pentose oxidation pathways: evidence for enzyme recruitment. J. Biol. Chem. 281 (2006) 27378–27388. [DOI] [PMID: 16849334]
2.  Brouns, S.J., Turnbull, A.P., Willemen, H.L., Akerboom, J. and van der Oost, J. Crystal structure and biochemical properties of the D-arabinose dehydrogenase from Sulfolobus solfataricus. J. Mol. Biol. 371 (2007) 1249–1260. [DOI] [PMID: 17610898]
[EC 1.1.1.427 created 2022]
 
 
EC 1.1.1.428
Accepted name: 4-methylthio 2-oxobutanoate reductase (NADH)
Reaction: (2R)-2-hydroxy-4-(methylsulfanyl)butanoate + NAD+ = 4-(methylsulfanyl)-2-oxobutanoate + NADH + H+
Other name(s): CTBP1 (gene name); C-terminal-binding protein 1; MTOB reductase; 4-methylthio 2-oxobutyrate reductase; 4-methylthio 2-oxobutyric acid reductase
Systematic name: (2R)-2-hydroxy-4-(methylsulfanyl)butanoate:NAD+ 2-oxidoreductase
Comments: The substrate of this enzyme is formed as an intermediate during L-methionine salvage from S-methyl-5′-thioadenosine, which is formed during the biosynthesis of polyamines. The human enzyme also functions as a transcriptional co-regulator that downregulates the expression of many tumor-suppressor genes, thus providing a link between gene repression and the methionine salvage pathway. A similar, but NADP-specific, enzyme is involved in dimethylsulfoniopropanoate biosynthesis in algae and phytoplankton.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Kumar, V., Carlson, J.E., Ohgi, K.A., Edwards, T.A., Rose, D.W., Escalante, C.R., Rosenfeld, M.G. and Aggarwal, A.K. Transcription corepressor CtBP is an NAD(+)-regulated dehydrogenase. Mol. Cell 10 (2002) 857–869. [DOI] [PMID: 12419229]
2.  Achouri, Y., Noel, G. and Van Schaftingen, E. 2-Keto-4-methylthiobutyrate, an intermediate in the methionine salvage pathway, is a good substrate for CtBP1. Biochem. Biophys. Res. Commun. 352 (2007) 903–906. [DOI] [PMID: 17157814]
3.  Hilbert, B.J., Grossman, S.R., Schiffer, C.A. and Royer, W.E., Jr. Crystal structures of human CtBP in complex with substrate MTOB reveal active site features useful for inhibitor design. FEBS Lett. 588 (2014) 1743–1748. [DOI] [PMID: 24657618]
4.  Korwar, S., Morris, B.L., Parikh, H.I., Coover, R.A., Doughty, T.W., Love, I.M., Hilbert, B.J., Royer, W.E., Jr., Kellogg, G.E., Grossman, S.R. and Ellis, K.C. Design, synthesis, and biological evaluation of substrate-competitive inhibitors of C-terminal Binding Protein (CtBP). Bioorg. Med. Chem. 24 (2016) 2707–2715. [DOI] [PMID: 27156192]
[EC 1.1.1.428 created 2022]
 
 
EC 1.1.1.429
Accepted name: (2S)-[(R)-hydroxy(phenyl)methyl]succinyl-CoA dehydrogenase
Reaction: (2S)-[(R)-hydroxy(phenyl)methyl]succinyl-CoA + NAD+ = (S)-2-benzoylsuccinyl-CoA + NADH + H+
Other name(s): bbsCD (gene name)
Systematic name: (2S)-[(R)-hydroxy(phenyl)methyl]succinyl-CoA:NAD+ oxidoreductase
Comments: The enzyme, purified from the bacterium Thauera aromatica, is involved in an anaerobic toluene degradation pathway. It is specific for NAD+.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  von Horsten, S., Lippert, M.L., Geisselbrecht, Y., Schuhle, K., Schall, I., Essen, L.O. and Heider, J. Inactive pseudoenzyme subunits in heterotetrameric BbsCD, a novel short-chain alcohol dehydrogenase involved in anaerobic toluene degradation. FEBS J. (2021) . [DOI] [PMID: 34601806]
[EC 1.1.1.429 created 2022]
 
 
*EC 1.1.3.29
Accepted name: N-acylhexosamine oxidase
Reaction: (1) N-acetyl-D-glucosamine + O2 + H2O = N-acetyl-D-glucosaminate + H2O2 (overall reaction)
(1a) N-acetyl-D-glucosamine + O2 = N-acetyl-D-glucosamino-1,5-lactone + H2O2
(1b) N-acetyl-D-glucosamino-1,5-lactone + H2O = N-acetyl-D-glucosaminate (spontaneous)
(2) N-acetyl-D-galactosamine + O2 + H2O = N-acetyl-D-galacotsaminate + H2O2 (overall reaction)
(2a) N-acetyl-D-galactosamine + O2 = N-acetyl-D-galactosamino-1,5-lactone + H2O2
(2b) N-acetyl-D-galactosamino-1,5-lactone + H2O = N-acetyl-D-galactosaminate (spontaneous)
Other name(s): N-acyl-D-hexosamine oxidase; N-acyl-β-D-hexosamine:oxygen 1-oxidoreductase
Systematic name: N-acyl-D-hexosamine:oxygen 1-oxidoreductase
Comments: The enzyme, found in bacteria, also acts more slowly on N-acetyl-D-mannosamine.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 121479-58-1
References:
1.  Horiuchi, T. Purification and properties of N-acyl-D-hexosamine oxidase from Pseudomonas sp. 15-1. Agric. Biol. Chem. 53 (1989) 361–368. [DOI]
2.  Rembeza, E., Boverio, A., Fraaije, M.W. and Engqvist, M.K.M. Discovery of two novel oxidases using a high-throughput activity screen. ChemBioChem (2021) . [DOI] [PMID: 34709726]
[EC 1.1.3.29 created 1992, modified 2022]
 
 
EC 1.3.3.17
Accepted name: benzylmalonyl-CoA dehydrogenase
Reaction: benzylmalonyl-CoA + O2 = (E)-cinnamoyl-CoA + CO2 + H2O2
Other name(s): iaaF (gene name)
Systematic name: benzylmalonyl-CoA:oxygen oxidoreductase (decarboxylating)
Comments: The enzyme, characterized from the bacterium Aromatoleum aromaticum, is involved in degradation of (indol-3-yl)acetate, where it is believed to function on (2-aminobenzyl)malonyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Schuhle, K., Saft, M., Vogeli, B., Erb, T.J. and Heider, J. Benzylmalonyl-CoA dehydrogenase, an enzyme involved in bacterial auxin degradation. Arch. Microbiol. 203 (2021) 4149–4159. [DOI] [PMID: 34059946]
[EC 1.3.3.17 created 2022]
 
 
EC 1.3.99.41
Accepted name: 3-(methylsulfanyl)propanoyl-CoA 2-dehydrogenase
Reaction: 3-(methylsulfanyl)propanoyl-CoA + acceptor = 3-(methylsulfanyl)acryloyl-CoA + reduced acceptor
Other name(s): dmdC (gene name)
Systematic name: 3-(methylsulfanyl)propanoyl-CoA:acceptor 2-oxidoreductase
Comments: The enzyme, found in marine bacteria, participates in a 3-(methylsulfanyl)propanoate degradation pathway. Based on similar enzymes, the in vivo electron acceptor is likely electron-transfer flavoprotein (ETF).
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Reisch, C.R., Stoudemayer, M.J., Varaljay, V.A., Amster, I.J., Moran, M.A. and Whitman, W.B. Novel pathway for assimilation of dimethylsulphoniopropionate widespread in marine bacteria. Nature 473 (2011) 208–211. [DOI] [PMID: 21562561]
2.  Bullock, H.A., Luo, H. and Whitman, W.B. Evolution of dimethylsulfoniopropionate metabolism in marine phytoplankton and bacteria. Front. Microbiol. 8:637 (2017). [DOI] [PMID: 28469605]
3.  Shao, X., Cao, H.Y., Zhao, F., Peng, M., Wang, P., Li, C.Y., Shi, W.L., Wei, T.D., Yuan, Z., Zhang, X.H., Chen, X.L., Todd, J.D. and Zhang, Y.Z. Mechanistic insight into 3-methylmercaptopropionate metabolism and kinetical regulation of demethylation pathway in marine dimethylsulfoniopropionate-catabolizing bacteria. Mol. Microbiol. 111 (2019) 1057–1073. [DOI] [PMID: 30677184]
[EC 1.3.99.41 created 2022]
 
 
*EC 1.5.3.1
Accepted name: sarcosine oxidase (formaldehyde-forming)
Reaction: sarcosine + H2O + O2 = glycine + formaldehyde + H2O2
Other name(s): MSOX; monomeric sarcosine oxidase; sarcosine oxidase (ambiguous)
Systematic name: sarcosine:oxygen oxidoreductase (demethylating)
Comments: The enzyme, reported from bacteria and fungi, catalyses the oxidative demethylation of sarcosine. It contains a FAD cofactor bound to an L-cysteine residue. cf. EC 1.5.3.24, sarcosine oxidase (5,10-methylenetetrahydrofolate-forming).
Links to other databases: BRENDA, EXPASY, KEGG, PDB, CAS registry number: 9029-22-5
References:
1.  Mori, N., Sano, M., Tani, Y. and Yamada, H. Purification and propertie of sarcosine oxidase from Cylindrocarpon didymum M-1. Agric. Biol. Chem. 44 (1980) 1391–1397.
2.  Nishiya, Y. and Imanaka, T. Cloning and sequencing of the sarcosine oxidase gene from Arthrobacter sp. TE1826. J. Ferment. Bioeng. 75 (1993) 239–244. [DOI]
3.  Nishiya, Y. and Imanaka, T. Alteration of substrate specificity and optimum pH of sarcosine oxidase by random and site-directed mutagenesis. Appl. Environ. Microbiol. 60 (1994) 4213–4215. [DOI] [PMID: 16349451]
4.  Trickey, P., Wagner, M.A., Jorns, M.S. and Mathews, F.S. Monomeric sarcosine oxidase: structure of a covalently flavinylated amine oxidizing enzyme. Structure 7 (1999) 331–345. [DOI] [PMID: 10368302]
5.  Wagner, M.A., Trickey, P., Chen, Z.W., Mathews, F.S. and Jorns, M.S. Monomeric sarcosine oxidase: 1. Flavin reactivity and active site binding determinants. Biochemistry 39 (2000) 8813–8824. [DOI] [PMID: 10913292]
6.  Zhao, G., Bruckner, R.C. and Jorns, M.S. Identification of the oxygen activation site in monomeric sarcosine oxidase: role of Lys265 in catalysis. Biochemistry 47 (2008) 9124–9135. [DOI] [PMID: 18693755]
7.  Jorns, M.S., Chen, Z.W. and Mathews, F.S. Structural characterization of mutations at the oxygen activation site in monomeric sarcosine oxidase. Biochemistry 49 (2010) 3631–3639. [DOI] [PMID: 20353187]
8.  Bucci, A., Yu, T.Q., Vanden-Eijnden, E. and Abrams, C.F. Kinetics of O2 entry and exit in monomeric sarcosine oxidase via Markovian milestoning molecular dynamics. J Chem Theory Comput 12 (2016) 2964–2972. [DOI] [PMID: 27168219]
[EC 1.5.3.1 created 1961, modified 2022]
 
 
EC 1.5.3.24
Accepted name: sarcosine oxidase (5,10-methylenetetrahydrofolate-forming)
Reaction: sarcosine + 5,6,7,8-tetrahydrofolate + O2 = glycine + 5,10-methylenetetrahydrofolate + H2O2
Other name(s): TSOX; sarcosine oxidase (ambigious); heterotetrameric sarcosine oxidase
Systematic name: sarcosine, 5,6,7,8-tetrahydrofolate:O2 oxidoreductase (demethylating,5,10-methylenetetrahydrofolate-forming)
Comments: The enzyme, found in some bacterial species, is composed of four different subunits and two active sites connected by a large "reaction chamber". An imine intermediate is transferred between the sites, eliminating the production of toxic formaldehyde. The enzyme contains three cofactors: noncovalently bound FAD and NAD+, and FMN that is covalently bound to a histidine residue. In the absence of folate the enzyme catalyses the reaction of EC 1.5.3.1, sarcosine oxidase (formaldehyde-forming).
Links to other databases: BRENDA, EXPASY, KEGG, PDB, CAS registry number: 9029-22-5
References:
1.  Hayashi, S., Nakamura, S. and Suzuki, M. Corynebacterium sarcosine oxidase: a unique enzyme having covalently-bound and noncovalently-bound flavins. Biochem. Biophys. Res. Commun. 96 (1980) 924–930. [DOI] [PMID: 6158947]
2.  Suzuki, M. Purification and some properties of sarcosine oxidase from Corynebacterium sp. U-96. J. Biochem. (Tokyo) 89 (1981) 599–607. [DOI] [PMID: 7240129]
3.  Chlumsky, L.J., Zhang, L., Ramsey, A.J. and Jorns, M.S. Preparation and properties of recombinant corynebacterial sarcosine oxidase: evidence for posttranslational modification during turnover with sarcosine. Biochemistry 32 (1993) 11132–11142. [DOI] [PMID: 7692961]
4.  Chlumsky, L.J., Sturgess, A.W., Nieves, E. and Jorns, M.S. Identification of the covalent flavin attachment site in sarcosine oxidase. Biochemistry 37 (1998) 2089–2095. [DOI] [PMID: 9485355]
5.  Eschenbrenner, M., Chlumsky, L.J., Khanna, P., Strasser, F. and Jorns, M.S. Organization of the multiple coenzymes and subunits and role of the covalent flavin link in the complex heterotetrameric sarcosine oxidase. Biochemistry 40 (2001) 5352–5367. [DOI] [PMID: 11330998]
[EC 1.5.3.24 created 2022]
 
 
*EC 1.5.8.3
Accepted name: sarcosine dehydrogenase
Reaction: sarcosine + 5,6,7,8-tetrahydrofolate + electron-transfer flavoprotein = glycine + 5,10-methylenetetrahydrofolate + reduced electron-transfer flavoprotein
Other name(s): sarcosine N-demethylase; monomethylglycine dehydrogenase; sarcosine:(acceptor) oxidoreductase (demethylating); sarcosine:electron-transfer flavoprotein oxidoreductase (demethylating)
Systematic name: sarcosine, 5,6,7,8-tetrahydrofolate:electron-transferflavoprotein oxidoreductase (demethylating,5,10-methylenetetrahydrofolate-forming)
Comments: A flavoprotein (FMN) found in eukaryotes. In the absence of tetrahydrofolate the enzyme produces formaldehyde. cf. EC 1.5.3.1, sarcosine oxidase (formaldehyde-forming), and EC 1.5.3.24, sarcosine oxidase (5,10-methylenetetrahydrofolate-forming).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 37228-65-2, 93389-49-2
References:
1.  Hoskins, D.D. and MacKenzie, C.G. Solubilization and electron transfer flavoprotein requirement of mitochondrial sarcosine dehydrogenase and dimethylglycine dehydrogenase. J. Biol. Chem. 236 (1961) 177–183. [DOI] [PMID: 13716069]
2.  Frisell, W.R. and MacKenzie, C.G. Separation and purification of sarcosine dehydrogenase and dimethylglycine dehydrogenase. J. Biol. Chem. 237 (1962) 94–98. [DOI] [PMID: 13895406]
3.  Wittwer, A.J. and Wagner, C. Identification of the folate-binding proteins of rat liver mitochondria as dimethylglycine dehydrogenase and sarcosine dehydrogenase. Flavoprotein nature and enzymatic properties of the purified proteins. J. Biol. Chem. 256 (1981) 4109–4115. [DOI] [PMID: 6163778]
4.  Steenkamp, D.J. and Husain, M. The effect of tetrahydrofolate on the reduction of electron transfer flavoprotein by sarcosine and dimethylglycine dehydrogenases. Biochem. J. 203 (1982) 707–715. [DOI] [PMID: 6180732]
[EC 1.5.8.3 created 1972 as EC 1.5.99.1, transferred 2012 to EC 1.5.8.3, modified 2022]
 
 
*EC 1.14.14.147
Accepted name: 22α-hydroxysteroid 23-monooxygenase
Reaction: (1) 3-epi-6-deoxocathasterone + [reduced NADPH—hemoprotein reductase] + O2 = 6-deoxotyphasterol + [oxidized NADPH—hemoprotein reductase] + H2O
(2) (22S,24R)-22-hydroxy-5α-ergostan-3-one + [reduced NADPH—hemoprotein reductase] + O2 = 3-dehydro-6-deoxoteasterone + [oxidized NADPH—hemoprotein reductase] + H2O
Other name(s): cytochrome P450 90C1; CYP90D1; CYP90C1; 3-epi-6-deoxocathasterone,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (C-23-hydroxylating); 3-epi-6-deoxocathasterone 23-monooxygenase
Systematic name: 22α-hydroxysteroid,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (C-23-hydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein involved in brassinosteroid biosynthesis in plants. The enzyme has a relaxed substrate specificity, and C-23 hydroxylation can occur at different stages in the pathway. In Arabidopsis thaliana two isozymes, encoded by the CYP90C1 and CYP90D1 genes, have redundant activities.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Kim, G.T., Fujioka, S., Kozuka, T., Tax, F.E., Takatsuto, S., Yoshida, S. and Tsukaya, H. CYP90C1 and CYP90D1 are involved in different steps in the brassinosteroid biosynthesis pathway in Arabidopsis thaliana. Plant J. 41 (2005) 710–721. [DOI] [PMID: 15703058]
2.  Ohnishi, T., Szatmari, A.M., Watanabe, B., Fujita, S., Bancos, S., Koncz, C., Lafos, M., Shibata, K., Yokota, T., Sakata, K., Szekeres, M. and Mizutani, M. C-23 hydroxylation by Arabidopsis CYP90C1 and CYP90D1 reveals a novel shortcut in brassinosteroid biosynthesis. Plant Cell 18 (2006) 3275–3288. [DOI] [PMID: 17138693]
[EC 1.14.14.147 created 2010 as EC 1.14.13.112, transferred 2018 to EC 1.14.14.147, modified 2022]
 
 
EC 1.14.14.178
Accepted name: steroid 22S-hydroxylase
Reaction: (1) a C27-steroid + O2 + [reduced NADPH—hemoprotein reductase] = a (22S)-22-hydroxy-C27-steroid + 2 H2O + [oxidized NADPH—hemoprotein reductase]
(2) a C28-steroid + O2 + [reduced NADPH—hemoprotein reductase] = a (22S)-22-hydroxy-C28-steroid + 2 H2O + [oxidized NADPH—hemoprotein reductase]
(3) a C29-steroid + O2 + [reduced NADPH—hemoprotein reductase] = a (22S)-22-hydroxy-C29-steroid + 2 H2O + [oxidized NADPH—hemoprotein reductase]
Other name(s): CYP90B1 (gene name); DWF4 (gene name); steroid C-22 hydroxylase
Systematic name: steroid,NADPH—hemoprotein reductase:oxygen 22S-oxidoreductase (hydroxylating)
Comments: This plant cytochrome P-450 (heme thiolate) enzyme participates in the biosynthesis of brassinosteroids. While in vivo substrates include C28-steroids such as campestanol, campesterol, and 6-oxocampestanol, the enzyme is able to catalyse the C-22 hydroxylation of a variety of C27, C28 and C29 steroids.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Asami, T., Mizutani, M., Fujioka, S., Goda, H., Min, Y.K., Shimada, Y., Nakano, T., Takatsuto, S., Matsuyama, T., Nagata, N., Sakata, K. and Yoshida, S. Selective interaction of triazole derivatives with DWF4, a cytochrome P450 monooxygenase of the brassinosteroid biosynthetic pathway, correlates with brassinosteroid deficiency in planta. J. Biol. Chem. 276 (2001) 25687–25691. [DOI] [PMID: 11319239]
2.  Choe, S., Fujioka, S., Noguchi, T., Takatsuto, S., Yoshida, S. and Feldmann, K.A. Overexpression of DWARF4 in the brassinosteroid biosynthetic pathway results in increased vegetative growth and seed yield in Arabidopsis. Plant J. 26 (2001) 573–582. [DOI] [PMID: 11489171]
3.  Asami, T., Mizutani, M., Shimada, Y., Goda, H., Kitahata, N., Sekimata, K., Han, S.Y., Fujioka, S., Takatsuto, S., Sakata, K. and Yoshida, S. Triadimefon, a fungicidal triazole-type P450 inhibitor, induces brassinosteroid deficiency-like phenotypes in plants and binds to DWF4 protein in the brassinosteroid biosynthesis pathway. Biochem. J. 369 (2003) 71–76. [DOI] [PMID: 12350224]
4.  Fujita, S., Ohnishi, T., Watanabe, B., Yokota, T., Takatsuto, S., Fujioka, S., Yoshida, S., Sakata, K. and Mizutani, M. Arabidopsis CYP90B1 catalyses the early C-22 hydroxylation of C27, C28 and C29 sterols. Plant J. 45 (2006) 765–774. [DOI] [PMID: 16460510]
5.  Ohnishi, T., Watanabe, B., Sakata, K. and Mizutani, M. CYP724B2 and CYP90B3 function in the early C-22 hydroxylation steps of brassinosteroid biosynthetic pathway in tomato. Biosci. Biotechnol. Biochem. 70 (2006) 2071–2080. [DOI] [PMID: 16960392]
[EC 1.14.14.178 created 2022]
 
 
EC 1.14.19.79
Accepted name: 3β,22α-dihydroxysteroid 3-dehydrogenase
Reaction: (1) (22S)-22-hydroxycampesterol + [reduced NADPH-hemoprotein reductase] + O2 = (22S)-22-hydroxycampest-4-en-3-one + [oxidized NADPH-hemoprotein reductase] + 2 H2O
(2) 6-deoxoteasterone + [reduced NADPH-hemoprotein reductase] + O2 = 3-dehydro-6-deoxoteasterone + [oxidized NADPH-hemoprotein reductase] + 2 H2O
Glossary: 6-deoxoteasterone = (22R,23R)-5α-campestane-3β,22,23-triol
Other name(s): CYP90A1 (gene name)
Systematic name: 3β,22α-dihydroxysteroid,[reduced NADPH-hemoprotein reductase]:oxygen 3-oxidoreductase
Comments: This cytochrome P-450 (heme-thiolate) enzyme, characterized from the plant Arabidopsis thaliana, catalyses C-3 dehydrogenation of all 3β-hydroxy brassinosteroid synthesis intermediates with 22-hydroxylated or 22,23-dihydroxylated side chains.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Ohnishi, T., Godza, B., Watanabe, B., Fujioka, S., Hategan, L., Ide, K., Shibata, K., Yokota, T., Szekeres, M. and Mizutani, M. CYP90A1/CPD, a brassinosteroid biosynthetic cytochrome P450 of Arabidopsis, catalyzes C-3 oxidation. J. Biol. Chem. 287 (2012) 31551–31560. [DOI] [PMID: 22822057]
[EC 1.14.19.79 created 2022]
 
 
EC 2.3.1.308
Accepted name: tubulin N-terminal N-acetyltransferase NAT9
Reaction: acetyl-CoA + an N-terminal-L-methionyl-[tubulin] = an N-terminal-Nα-acetyl-L-methionyl-[tubulin] + CoA
Other name(s): NAT9 (gene name); microtubule-associated N-acetyltransferase NAT9
Systematic name: acetyl-CoA:N-terminal-Met-[tubulin] Met-Nα-acetyltransferase
Comments: The enzyme, characterized from the fruit fly (Drosophila melanogaster), acetylates the N-terminal of both α- and β-tubulin. The enzyme acts cotranslationally, and can't act on a preformed tubulin α/β heterodimer.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Mok, J.W. and Choi, K.W. Novel function of N-acetyltransferase for microtubule stability and JNK signaling in Drosophila organ development. Proc. Natl. Acad. Sci. USA 118 (2021) . [DOI] [PMID: 33479178]
[EC 2.3.1.308 created 2022]
 
 
EC 2.4.1.387
Accepted name: isomaltosyltransferase
Reaction: (1) 2 α-isomaltosyl-(1→4)-maltotriose = α-isomaltosyl-(1→3)-α-isomaltosyl-(1→4)-maltotriose + maltotriose
(2) α-isomaltosyl-(1→3)-α-isomaltosyl-(1→4)-maltotriose = cyclobis-(1→6)-α-nigerosyl + maltotriose
Systematic name: α-isomaltosyl-(1→3)-1,4-α-D-glucan:1,4-α-D-glucan 3-α-isomaltosyltransferase
Comments: The enzyme, found in bacteria that produce cyclobis-(1→6)-α-nigerosyl, acts on the products of EC 2.4.1.24, 1,4-α-glucan 6-α;-glucosyltransferase. It catalyses the α-(1→3) transfer of the isomaltosyl moiety of one substrate to another, resulting in α-isomaltosyl-(1→3)-α-isomaltosyl-α-(1→4)-glucan formation. In addition, the enzyme catalyses the intramolecular cyclization of the product, eventually generating cyclobis-(1→6)-α-nigerosyl.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Aga, H., Maruta, K., Yamamoto, T., Kubota, M., Fukuda, S., Kurimoto, M. and Tsujisaka, Y. Cloning and sequencing of the genes encoding cyclic tetrasaccharide-synthesizing enzymes from Bacillus globisporus C11. Biosci. Biotechnol. Biochem. 66 (2002) 1057–1068. [DOI] [PMID: 12092816]
2.  Nishimoto, T., Aga, H., Mukai, K., Hashimoto, T., Watanabe, H., Kubota, M., Fukuda, S., Kurimoto, M. and Tsujisaka, Y. Purification and characterization of glucosyltransferase and glucanotransferase involved in the production of cyclic tetrasaccharide in Bacillus globisporus C11. Biosci. Biotechnol. Biochem. 66 (2002) 1806–1818. [DOI] [PMID: 12400677]
3.  Kim, Y.K., Kitaoka, M., Hayashi, K., Kim, C.H. and Cote, G.L. A synergistic reaction mechanism of a cycloalternan-forming enzyme and a D-glucosyltransferase for the production of cycloalternan in Bacillus sp. NRRL B-21195. Carbohydr. Res. 338 (2003) 2213–2220. [DOI] [PMID: 14553982]
[EC 2.4.1.387 created 2022]
 
 
EC 2.4.1.388
Accepted name: glucosylgalactose phosphorylase
Reaction: β-D-glucosyl-(1→4)-D-galactose + phosphate = α-D-glucopyranose 1-phosphate + D-galactopyranose
Other name(s): 4-O-β-D-glucosyl-D-galactose phosphorylase
Systematic name: β-D-glucosyl-(1→4)-D-galactose:phosphate α-D-glucosyltransferase (configuration-inverting)
Comments: The enzyme from the bacterium Paenibacillus polymyxa belongs to glycoside hydrolase family 94. It has a much lower activity with 4-O-β-D-glucosyl-L-arabinose.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  De Doncker, M., De Graeve, C., Franceus, J., Beerens, K., Kren, V., Pelantova, H., Vercauteren, R. and Desmet, T. Exploration of GH94 sequence space for enzyme discovery reveals a novel glucosylgalactose phosphorylase specificity. ChemBioChem (2021) . [DOI] [PMID: 34541742]
[EC 2.4.1.388 created 2022]
 
 
EC 2.4 Glycosyltransferases
 
EC 2.4.3 Sialyltransferases
 
EC 2.4.3.1
Accepted name: β-galactoside α-(2,6)-sialyltransferase
Reaction: CMP-N-acetyl-β-neuraminate + β-D-galactosyl-R = CMP + N-acetyl-α-neuraminyl-(2→6)-β-D-galactosyl-R
Other name(s): ST6Gal-I; CMP-N-acetylneuraminate:β-D-galactosyl-1,4-N-acetyl-β-D-glucosamine α-2,6-N-acetylneuraminyltransferase; lactosylceramide α-2,6-N-sialyltransferase; CMP-N-acetylneuraminate:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosamine α-(2→6)-N-acetylneuraminyltransferase; β-galactoside α-2,6-sialyltransferase
Systematic name: CMP-N-acetyl-β-neuraminate:β-D-galactoside α-(2→6)-N-acetylneuraminyltransferase (configuration-inverting)
Comments: The enzyme acts on the terminal non-reducing β-D-galactosyl residue of the oligosaccharide moiety of glycoproteins and glycolipids.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 9075-81-4
References:
1.  Spiro, M.H. and Spiro, R.G. Glycoprotein biosynthesis: studies on thyroglobulin. Thyroid sialyltransferase. J. Biol. Chem. 243 (1968) 6520–6528. [PMID: 5726897]
2.  Hickman, J., Ashwell, G., Morell, A.G., van der Hamer, C.J.A. and Scheinberg, I.H. Physical and chemical studies on ceruloplasmin. 8. Preparation of N-acetylneuraminic acid-1-14C-labeled ceruloplasmin. J. Biol. Chem. 245 (1970) 759–766. [PMID: 4313609]
3.  Bartholomew, B.A., Jourdian, G.W. and Roseman, S. The sialic acids. XV. Transfer of sialic acid to glycoproteins by a sialyltransferase from colostrum. J. Biol. Chem. 248 (1973) 5751–5762. [PMID: 4723915]
4.  Paulson, J.C., Beranek, W.E. and Hill, R.L. Purification of a sialyltransferase from bovine colostrum by affinity chromatography on CDP-agarose. J. Biol. Chem. 252 (1977) 2356–2362. [PMID: 849932]
5.  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]
6.  Albarracin, I., Lassaga, F.E. and Caputto, R. Purification and characterization of an endogenous inhibitor of the sialyltransferase CMP-N-acetylneuraminate: lactosylceramide α2,6-N-acetylneuraminyltransferase (EC 2.4.99.-). Biochem. J. 254 (1988) 559–565. [PMID: 2460092]
[EC 2.4.3.1 created 1972 as EC 2.4.99.1, modified 1976, modified 1986, modified 2017 (EC 2.4.99.11 created 1992, incorporated 2016), modified 2017, transferred 2021 to EC 2.4.3.1]
 
 
EC 2.4.3.2
Accepted name: β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase
Reaction: CMP-N-acetyl-β-neuraminate + a β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-R = CMP + an N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-R
For diagram of ganglioside biosynthesis, click here
Glossary: a β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-(1→4)-[N-acetyl-α-neuraminyl-(2→3)]-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide = gangloside GM1a
an N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-(1→4)-[N-acetyl-α-neuraminyl-(2→3)]-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide = gangloside GD1a
Other name(s): CMP-N-acetylneuraminate:D-galactosyl-N-acetyl-D-galactosaminyl-(N-acetylneuraminyl)-D-galactosyl-D-glucosyl-(1↔1)-ceramide N-acetylneuraminyltransferase (ambiguous); monosialoganglioside sialyltransferase; CMP-N-acetylneuraminate:a β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-(1→4)-[α-N-acetylneuraminyl-(2→3)]-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide N-acetyl-β-neuraminyltransferase
Systematic name: CMP-N-acetyl-β-neuraminate:a β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminyl-R α-(2→3)-N-acetylneuraminyltransferase (configuration-inverting)
Comments: The enzyme recognizes the sequence β-D-galactosyl-(1→3)-N-acetyl-D-galactosaminyl (known as type 1 histo-blood group precursor disaccharide) in non-reducing termini of glycan moieties in glycoproteins and glycolipids [1]. When acting on gangloside GM1a, it forms gangloside GD1a [2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 60202-12-2
References:
1.  Rearick, J.I., Sadler, J.E., Paulson, J.C. and Hill, R.L. Enzymatic characterization of β D-galactoside α2→3 sialyltransferase from porcine submaxillary gland. J. Biol. Chem. 254 (1979) 4444–4451. [PMID: 438198]
2.  Yip, M.C.M. The enzymic synthesis of disialoganglioside: rat brain cytidine-5′-monophospho-N-acetylneuraminic acid: monosialoganglioside (GM1) sialyltransferase. Biochim. Biophys. Acta 306 (1973) 298–306. [DOI] [PMID: 4351506]
[EC 2.4.3.2 created 1976 as EC 2.4.99.2, modified 1986, modified 2017, transferred 2022 to EC 2.4.3.2]
 
 
EC 2.4.3.3
Accepted name: α-N-acetylgalactosaminide α-2,6-sialyltransferase
Reaction: CMP-N-acetylneuraminate + glycano-(1→3)-(N-acetyl-α-D-galactosaminyl)-glycoprotein = CMP + glycano-[(2→6)-α-N-acetylneuraminyl]-(N-acetyl-D-galactosaminyl)-glycoprotein
Systematic name: CMP-N-acetylneuraminate:glycano-1,3-(N-acetyl-α-D-galactosaminyl)-glycoprotein α-2,6-N-acetylneuraminyltransferase
Comments: N-acetyl-α-D-galactosamine linked to threonine or serine is also an acceptor, when substituted at the 3-position.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 71124-50-0
References:
1.  Sadler, J.E., Rearick, J.I. and Hill, R.L. Purification to homogeneity and enzymatic characterization of an α-N-acetylgalactosaminide α2→6 sialyltransferase from porcine submaxillary glands. J. Biol. Chem. 254 (1979) 5934–5941. [PMID: 447688]
[EC 2.4.3.3 created 1984 as EC 2.4.99.3, modified 1986, transferred 2022 to EC 2.4.3.3]
 
 
EC 2.4.3.4
Accepted name: β-galactoside α-2,3-sialyltransferase
Reaction: CMP-N-acetylneuraminate + β-D-galactosyl-(1→3)-N-acetyl-α-D-galactosaminyl-R = CMP + α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-α-D-galactosaminyl-R
Other name(s): CMP-N-acetylneuraminate:β-D-galactoside α-2,3-N-acetylneuraminyl-transferase
Systematic name: CMP-N-acetylneuraminate:β-D-galactoside α-(2→3)-N-acetylneuraminyl-transferase
Comments: The acceptor is Galβ1,3GalNAc-R, where R is H, a threonine or serine residue in a glycoprotein, or a glycolipid. Lactose can also act as acceptor. May be identical with EC 2.4.3.2 β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 71124-51-1
References:
1.  Rearick, J.I., Sadler, J.E., Paulson, J.C. and Hill, R.L. Enzymatic characterization of β D-galactoside α2→3 sialyltransferase from porcine submaxillary gland. J. Biol. Chem. 254 (1979) 4444–4451. [PMID: 438198]
2.  Sadler, J.E., Rearick, J.I., Paulson, J.C. and Hill, R.L. Purification to homogeneity of a β-galactoside α2→3 sialyltransferase and partial purification of an α-N-acetylgalactosaminide α2→6 sialyltransferase from porcine submaxillary glands. J. Biol. Chem. 254 (1979) 4434–4442. [PMID: 438196]
[EC 2.4.3.4 created 1984 as EC 2.4.99.4, modified 1986, transferred 2022 to EC 2.4.3.4]
 
 
EC 2.4.3.5
Accepted name: galactosyldiacylglycerol α-2,3-sialyltransferase
Reaction: CMP-N-acetyl-β-neuraminate + 1,2-diacyl-3-β-D-galactosyl-sn-glycerol = CMP + 1,2-diacyl-3-[3-(N-acetyl-α-D-neuraminyl)-β-D-galactosyl]-sn-glycerol
Systematic name: CMP-N-acetyl-β-neuraminate:1,2-diacyl-3-β-D-galactosyl-sn-glycerol N-acetylneuraminyltransferase
Comments: The β-D-galactosyl residue of the oligosaccharide of glycoproteins may also act as acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 80237-98-5
References:
1.  Pieringer, J., Keech, S. and Pieringer, R.A. Biosynthesis in vitro of sialosylgalactosyldiacylglycerol by mouse brain microsomes. J. Biol. Chem. 256 (1981) 12306–12309. [PMID: 7298658]
2.  Weinstein, J., de Souza-e-Silva, U. and Paulson, J.C. Purification of a Gal β1→4GlcNAc α2→6 sialyltransferase and a Gal β1→3(4)GlcNAc α2→3 sialyltransferase to homogeneity from rat liver. J. Biol. Chem. 257 (1982) 13835–13844. [PMID: 7142179]
3.  Weinstein, J., de Souza-e-Silva, U. and Paulson, J.C. Sialylation of glycoprotein oligosaccharides N-linked to asparagine. Enzymatic characterization of a Gal β1→3(4)GlcNAc α2→3 sialyltransferase and a Gal β1→4GlcNAc α2→6 sialyltransferase from rat liver. J. Biol. Chem. 257 (1982) 13845–13853. [PMID: 7142180]
[EC 2.4.3.5 created 1984 as EC 2.4.99.5, modified 1986, transferred 2022 to EC 2.4.3.5]
 
 
EC 2.4.3.6
Accepted name: N-acetyllactosaminide α-2,3-sialyltransferase
Reaction: CMP-N-acetyl-β-neuraminate + β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R = CMP + N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R
Other name(s): cytidine monophosphoacetylneuraminate-β-galactosyl(1→4)acetylglucosaminide α2→3-sialyltransferase; α2→3 sialyltransferase (ambiguous); SiaT (ambiguous); CMP-N-acetylneuraminate:β-D-galactosyl-1,4-N-acetyl-D-glucosaminyl-glycoprotein α-2,3-N-acetylneuraminyltransferase; neolactotetraosylceramide α-2,3-sialyltransferase; CMP-N-acetylneuraminate:β-D-galactosyl-(1→4)-N-acetyl-D-glucosaminyl-glycoprotein α-(2→3)-N-acetylneuraminyltransferase
Systematic name: CMP-N-acetyl-β-neuraminate:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R (2→3)-N-acetyl-α-neuraminyltransferase (configuration-inverting)
Comments: The enzyme recognizes the sequence β-D-galactosyl-(1→4)-N-acetyl-D-glucosaminyl (known as type 2 histo-blood group precursor disaccharide) in non-reducing termini of glycan moieties in glycoproteins and glycolipids. The enzyme from chicken brain was shown to act on neolactotetraosylceramide, producing ganglioside LM1 [2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 77537-85-0
References:
1.  Van den Eijnden, D.H. and Schiphorst, W.E.C.M. Detection of β-galactosyl(1→4)N-acetylglucosaminide α(2→3)-sialyltransferase activity in fetal calf liver and other tissues. J. Biol. Chem. 256 (1981) 3159–3162. [PMID: 7204397]
2.  Basu, M., Basu, S., Stoffyn, A. and Stoffyn, P. Biosynthesis in vitro of sialyl(α2-3)neolactotetraosylceramide by a sialyltransferase from embryonic chicken brain. J. Biol. Chem. 257 (1982) 12765–12769. [PMID: 7130178]
[EC 2.4.3.6 created 1984 as EC 2.4.99.6, modified 1986 (EC 2.4.99.10 created 1986, incorporated 2017), transferred 2022 to EC 2.4.3.6]
 
 
EC 2.4.3.7
Accepted name: α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylgalactosaminide 6-α-sialyltransferase
Reaction: CMP-N-acetylneuraminate + N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-D-galactosaminyl-R = CMP + N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-[N-acetyl-α-neuraminyl-(2→6)]-N-acetyl-D-galactosaminyl-R
For diagram of reaction, click here
Other name(s): sialyltransferase; cytidine monophosphoacetylneuraminate-(α-N-acetylneuraminyl-2,3-β-galactosyl-1,3)-N-acetylgalactosaminide-α-2,6-sialyltransferase; α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetyl-galactosaminide α-2,6-sialyltransferase; SIAT7; ST6GALNAC; (α-N-acetylneuraminyl-2,3-β-galactosyl-1,3)-N-acetyl-galactosaminide 6-α-sialyltransferase; CMP-N-acetylneuraminate:(α-N-acetylneuraminyl-2,3-β-D-galactosyl-1,3)-N-acetyl-D-galactosaminide α-2,6-N-acetylneuraminyl-transferase
Systematic name: CMP-N-acetylneuraminate:N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)- N-acetyl-D-galactosaminide galactosamine-6-α-N-acetylneuraminyltransferase
Comments: Attaches N-acetylneuraminic acid in α-2,6-linkage to N-acetylgalactosamine only when present in the structure of α-N-acetylneuraminyl-(2→3)-β-galactosyl-(1→3)-N-acetylgalactosaminyl-R, where R may be protein or p-nitrophenol. Not identical with EC 2.4.3.3 α-N-acetylgalactosaminide α-2,6-sialyltransferase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 129924-24-9
References:
1.  Bergh, M.L.E., Hooghwinkel, G.J.M. and Van den Eijnden, D.H. Biosynthesis of the O-glycosidically linked oligosaccharide chains of fetuin. Indications for an α-N-acetylgalactosaminide α2→6 sialyltransferase with a narrow acceptor specificity in fetal calf liver. J. Biol. Chem. 258 (1983) 7430–7436. [PMID: 6190802]
[EC 2.4.3.7 created 1984 as EC 2.4.99.7, modified 1986, modified 2004, transferred 2022 to EC 2.4.3.7]
 
 
EC 2.4.3.8
Accepted name: α-N-acetylneuraminate α-2,8-sialyltransferase
Reaction: CMP-N-acetylneuraminate + α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-R = CMP + α-N-acetylneuraminyl-(2→8)-α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-R
For diagram of ganglioside biosynthesis (pathway to GD3), click here
Other name(s): cytidine monophosphoacetylneuraminate-ganglioside GM3; α-2,8-sialyltransferase; ganglioside GD3 synthase; ganglioside GD3 synthetase sialyltransferase; CMP-NeuAc:LM1(α2-8) sialyltranferase; GD3 synthase; SAT-2
Systematic name: CMP-N-acetylneuraminate:α-N-acetylneuraminyl-(2→3)-β-D-galactoside α-(2→8)-N-acetylneuraminyltransferase
Comments: Gangliosides act as acceptors.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 67339-00-8
References:
1.  Eppler, M.C., Morré, J.D. and Keenan, T.W. Ganglioside biosynthesis in rat liver: alteration of sialyltransferase activities by nucleotides. Biochim. Biophys. Acta 619 (1980) 332–343. [DOI] [PMID: 7407217]
2.  Higashi, H., Basu, M. and Basu, S. Biosynthesis in vitro of disialosylneolactotetraosylceramide by a solubilized sialyltransferase from embryonic chicken brain. J. Biol. Chem. 260 (1985) 824–828. [PMID: 3838172]
3.  McCoy, R.D., Vimr, E.R. and Troy, F.A. CMP-NeuNAc:poly-α-2,8-sialosyl sialyltransferase and the biosynthesis of polysialosyl units in neural cell adhesion molecules. J. Biol. Chem. 260 (1985) 12695–12699. [PMID: 4044605]
4.  Yohe, H.C. and Yu, R.K. In vitro biosynthesis of an isomer of brain trisialoganglioside, GT1a. J. Biol. Chem. 255 (1980) 608–613. [PMID: 6766128]
[EC 2.4.3.8 created 1984 as EC 2.4.99.8, modified 1986, transferred 2022 to EC 2.4.3.8]
 
 
EC 2.4.3.9
Accepted name: lactosylceramide α-2,3-sialyltransferase
Reaction: CMP-N-acetylneuraminate + β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide = CMP + α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide
For diagram of ganglioside biosynthesis (pathway to GM2), click here
Glossary: lactosylceramide = β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide
Other name(s): cytidine monophosphoacetylneuraminate-lactosylceramide α2,3- sialyltransferase; CMP-acetylneuraminate-lactosylceramide-sialyltransferase; CMP-acetylneuraminic acid:lactosylceramide sialyltransferase; CMP-sialic acid:lactosylceramide-sialyltransferase; cytidine monophosphoacetylneuraminate-lactosylceramide sialyltransferase; ganglioside GM3 synthetase; GM3 synthase; GM3 synthetase; SAT 1; CMP-N-acetylneuraminate:lactosylceramide α-2,3-N-acetylneuraminyltransferase; CMP-N-acetylneuraminate:β-D-galactosyl-(1→4)-β-D-glucosyl(1↔1)ceramide α-(2→3)-N-acetylneuraminyltransferase
Systematic name: CMP-N-acetylneuraminate:β-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide α-(2→3)-N-acetylneuraminyltransferase
Comments: Lactose cannot act as acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 125752-90-1
References:
1.  Basu, S., Kaufman, B. and Roseman, S. Enzymatic synthesis of glucocerebroside by a glucosyltransferase from embryonic chicken brain. J. Biol. Chem. 248 (1973) 1388–1394. [PMID: 4631392]
2.  Fishman, P.H., Bradley, R.M. and Henneberry, R.C. Butyrate-induced glycolipid biosynthesis in HeLa cells: properties of the induced sialyltransferase. Arch. Biochem. Biophys. 172 (1976) 618–626. [DOI] [PMID: 4022]
3.  Higashi, H., Basu, M. and Basu, S. Biosynthesis in vitro of disialosylneolactotetraosylceramide by a solubilized sialyltransferase from embryonic chicken brain. J. Biol. Chem. 260 (1985) 824–828. [PMID: 3838172]
[EC 2.4.3.9 created 1984 as EC 2.4.99.9, modified 1986, transferred 2022 to EC 2.4.3.9]
 
 
EC 2.4.3.10
Accepted name: N-acetylglucosaminide α-(2,6)-sialyltransferase
Reaction: CMP-N-acetyl-β-neuraminate + N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-β-D-glucosaminyl-R = CMP + N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-[N-acetyl-α-neuraminyl-(2→6)]-N-acetyl-β-D-glucosaminyl-R
Other name(s): α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylglucosaminide 6-α-sialyltransferase; N-acetylglucosaminide (α 2→6)-sialyltransferase; ST6GlcNAc
Systematic name: CMP-N-acetylneuraminate:N-acetyl-α-neuraminyl-(2→3)-β-D-galactosyl-(1→3)-N-acetyl-β-D-glucosaminide N-acetyl-β-D-glucosamine-6-α-N-acetylneuraminyltransferase (configuration-inverting)
Comments: Attaches N-acetylneuraminic acid in α-2,6-linkage to N-acetyl-β-D-glucosamine. The enzyme from rat liver also acts on β-D-galactosyl-(1→3)-N-acetyl-β-D-glucosaminyl residues, but more slowly.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Paulson, J.C., Weinstein, J. and de Souza-e-Silva, U. Biosynthesis of a disialylated sequence in N-linked oligosaccharides: identification of an N-acetylglucosaminide (α 2→6)-sialyltransferase in Golgi apparatus from rat liver. Eur. J. Biochem. 140 (1984) 523–530. [PMID: 6547092]
[EC 2.4.3.10 created 2020 as EC 2.4.99.22, transferred 2022 to EC 2.4.3.10]
 
 
EC 2.4.99.1
Transferred entry: β-galactoside α-(2,6)-sialyltransferase. Now EC 2.4.3.1, β-galactoside α-(2,6)-sialyltransferase
[EC 2.4.99.1 created 1972, modified 1976, modified 1986, modified 2017 (EC 2.4.99.11 created 1992, incorporated 2017), deleted 2022]
 
 
EC 2.4.99.2
Transferred entry: β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase. Now EC 2.4.3.2, β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase
[EC 2.4.99.2 created 1976, modified 1986, deleted 2022]
 
 
EC 2.4.99.3
Transferred entry: α-N-acetylgalactosaminide α-2,6-sialyltransferase. Now EC 2.4.3.3, α-N-acetylgalactosaminide α-2,6-sialyltransferase
[EC 2.4.99.3 created 1984, modified 1986, deleted 2022]
 
 
EC 2.4.99.4
Transferred entry: β-galactoside α-2,3-sialyltransferase. Now EC 2.4.3.4, β-galactoside α-2,3-sialyltransferase
[EC 2.4.99.4 created 1984, modified 1986, deleted 2022]
 
 
EC 2.4.99.5
Transferred entry: galactosyldiacylglycerol α-2,3-sialyltransferase. Now EC 2.4.3.5, galactosyldiacylglycerol α-2,3-sialyltransferase
[EC 2.4.99.5 created 1984, modified 1986, deleted 2022]
 
 
EC 2.4.99.6
Transferred entry: N-acetyllactosaminide α-2,3-sialyltransferase. Now EC 2.4.3.6, N-acetyllactosaminide α-2,3-sialyltransferase
[EC 2.4.99.6 created 1984, modified 1986 (EC 2.4.99.10 created 1986, incorporated 2017), deleted 2022]
 
 
EC 2.4.99.7
Transferred entry: α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylgalactosaminide 6-α-sialyltransferase. Now EC 2.4.3.7, α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylgalactosaminide 6-α-sialyltransferase
[EC 2.4.99.7 created 1984, modified 1986, modified 2004, deleted 2022]
 
 
EC 2.4.99.8
Transferred entry: α-N-acetylneuraminate α-2,8-sialyltransferase. Now EC 2.4.3.8, α-N-acetylneuraminate α-2,8-sialyltransferase
[EC 2.4.99.8 created 1984, modified 1986, deleted 2022]
 
 
EC 2.4.99.9
Transferred entry: lactosylceramide α-2,3-sialyltransferase. Now EC 2.4.3.9, lactosylceramide α-2,3-sialyltransferase
[EC 2.4.99.9 created 1984, modified 1986, deleted 2022]
 
 
EC 2.4.99.10
Transferred entry: neolactotetraosylceramide α-2,3-sialyltransferase. Now included in EC 2.4.3.6, N-acetyllactosaminide α-2,3-sialyltransferase
[EC 2.4.99.10 created 1986, deleted 2017]
 
 
EC 2.4.99.22
Transferred entry: N-acetylglucosaminide α-(2,6)-sialyltransferase. Now EC 2.4.3.10, N-acetylglucosaminide α-(2,6)-sialyltransferase
[EC 2.4.99.22 created 2020, deleted 2022]
 
 
*EC 2.6.1.85
Accepted name: aminodeoxychorismate synthase
Reaction: chorismate + L-glutamine = 4-amino-4-deoxychorismate + L-glutamate (overall reaction)
(1a) L-glutamine + H2O = L-glutamate + NH3
(1b) chorismate + NH3 = 4-amino-4-deoxychorismate + H2O
For diagram of folate biosynthesis (late stages), click here
Other name(s): ADC synthase; 4-amino-4-deoxychorismate synthase; PabAB; chorismate:L-glutamine amido-ligase (incorrect)
Systematic name: chorismate:L-glutamine aminotransferase
Comments: The enzyme is composed of two parts, a glutaminase (PabA in Escherichia coli) and an aminotransferase (PabB). In the absence of PabA and glutamine (but in the presence of Mg2+), PabB can convert ammonia and chorismate into 4-amino-4-deoxychorismate. PabA converts glutamine into glutamate only in the presence of stoichiometric amounts of PabB. In many organisms, including plants, the genes encoding the two proteins have fused to encode a single bifunctional protein. This enzyme is coupled with EC 4.1.3.38, aminodeoxychorismate lyase, to form 4-aminobenzoate. cf. EC 2.6.1.123, 4-amino-4-deoxychorismate synthase (2-amino-4-deoxychorismate-forming).
Links to other databases: BRENDA, EXPASY, KEGG, PDB
References:
1.  Ye, Q.Z., Liu, J. and Walsh, C.T. p-Aminobenzoate synthesis in Escherichia coli: purification and characterization of PabB as aminodeoxychorismate synthase and enzyme X as aminodeoxychorismate lyase. Proc. Natl. Acad. Sci. USA 87 (1990) 9391–9395. [DOI] [PMID: 2251281]
2.  Viswanathan, V.K., Green, J.M. and Nichols, B.P. Kinetic characterization of 4-amino 4-deoxychorismate synthase from Escherichia coli. J. Bacteriol. 177 (1995) 5918–5923. [DOI] [PMID: 7592344]
3.  Chang, Z., Sun, Y., He, J. and Vining, L.C. p-Aminobenzoic acid and chloramphenicol biosynthesis in Streptomyces venezuelae: gene sets for a key enzyme, 4-amino-4-deoxychorismate synthase. Microbiology (Reading) 147 (2001) 2113–2126. [DOI] [PMID: 11495989]
4.  Camara, D., Richefeu-Contesto, C., Gambonnet, B., Dumas, R. and Rebeille, F. The synthesis of pABA: Coupling between the glutamine amidotransferase and aminodeoxychorismate synthase domains of the bifunctional aminodeoxychorismate synthase from Arabidopsis thaliana. Arch. Biochem. Biophys. 505 (2011) 83–90. [DOI] [PMID: 20851095]
[EC 2.6.1.85 created 2003 as EC 6.3.5.8, transferred 2007 to EC 2.6.1.85, modified 2022]
 
 
EC 2.7.1.236
Accepted name: NAD+ 3′-kinase
Reaction: ATP + NAD+ = ADP + 3′-NADP+
Glossary: 3′-NADP = nicotinamide adenine dinucleotide 3′-phosphate
Other name(s): AvrRxo1
Systematic name: ATP:NAD+ 3′-phosphotransferase
Comments: The enzyme, best characterized from the plant pathogenic bacterium Xanthomonas oryzae pv. oryzicola, is considered a bacterial type III effector. The product, 3′-NADP, is believed to enhance bacterial virulence on plants through manipulation of primary metabolic pathways. In vitro the enzyme is also active with nicotinate adenine dinucleotide (deamido-NAD).
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Schuebel, F., Rocker, A., Edelmann, D., Schessner, J., Brieke, C. and Meinhart, A. 3′-NADP and 3′-NAADP, Two Metabolites Formed by the Bacterial Type III Effector AvrRxo1. J. Biol. Chem. 291 (2016) 22868–22880. [DOI] [PMID: 27621317]
2.  Shidore, T., Broeckling, C.D., Kirkwood, J.S., Long, J.J., Miao, J., Zhao, B., Leach, J.E. and Triplett, L.R. The effector AvrRxo1 phosphorylates NAD in planta. PLoS Pathog. 13:e1006442 (2017). [DOI] [PMID: 28628666]
[EC 2.7.1.236 created 2022]
 
 
*EC 2.7.8.7
Accepted name: holo-[acyl-carrier-protein] synthase
Reaction: CoA-[4′-phosphopantetheine] + an apo-[acyl-carrier protein] = adenosine 3′,5′-bisphosphate + an [acyl-carrier protein]
Glossary: apo-[acyl-carrier protein] = a family of proteins or protein domains that contain a conserved serine residue, which are involved in acyl-group transfer.
[acyl-carrier protein] = holo-[acyl-carrier protein] = ACP = holo-ACP = the active form of apo-[acyl-carrier protein], in which the hydroxyl group of the conserved serine is substituted by a 4′-phosphopantetheine group, resulting in a sulfydryl group at which the acyl group to be transferred may then be substituted.
Other name(s): acyl carrier protein holoprotein (holo-ACP) synthetase; holo-ACP synthetase; coenzyme A:fatty acid synthetase apoenzyme 4′-phosphopantetheine transferase; holosynthase; acyl carrier protein synthetase; holo-ACP synthase; PPTase; AcpS; ACPS; acyl carrier protein synthase; P-pant transferase; CoA:apo-[acyl-carrier-protein] pantetheinephosphotransferase; CoA-[4′-phosphopantetheine]:apo-[acyl-carrier-protein] 4′-pantetheinephosphotransferase
Systematic name: CoA-[4′-phosphopantetheine]:apo-[acyl-carrier protein] 4′-pantetheinephosphotransferase
Comments: Requires Mg2+. All polyketide synthases, fatty-acid synthases and non-ribosomal peptide synthases require post-translational modification of their constituent acyl-carrier-protein (ACP) domains to become catalytically active. The inactive apo-proteins are converted into their active holo-forms by transfer of the 4′-phosphopantetheinyl moiety of CoA to the sidechain hydroxy group of a conserved serine residue in each ACP domain [3]. The enzyme from human can activate both the ACP domain of the human cytosolic multifunctional fatty-acid synthase system (EC 2.3.1.85) and that associated with human mitochondria as well as peptidyl-carrier and acyl-carrier-proteins from prokaryotes [6]. Removal of the 4-phosphopantetheinyl moiety from holo-ACP is carried out by EC 3.1.4.14, [acyl-carrier-protein] phosphodiesterase.
Links to other databases: BRENDA, EXPASY, KEGG, PDB, CAS registry number: 37278-30-1
References:
1.  Elovson, J. and Vagelos, P.R. Acyl carrier protein. X. Acyl carrier protein synthetase. J. Biol. Chem. 243 (1968) 3603–3611. [PMID: 4872726]
2.  Prescott, D.J. and Vagelos, P.R. Acyl carrier protein. Adv. Enzymol. Relat. Areas Mol. Biol. 36 (1972) 269–311. [PMID: 4561013]
3.  Lambalot, R.H., Gehring, A.M., Flugel, R.S., Zuber, P., LaCelle, M., Marahiel, M.A., Reid, R., Khosla, C. and Walsh, C.T. A new enzyme superfamily - the phosphopantetheinyl transferases. Chem. Biol. 3 (1996) 923–936. [DOI] [PMID: 8939709]
4.  Walsh, C.T., Gehring, A.M., Weinreb, P.H., Quadri, L.E.N. and Flugel, R.S. Post-translational modification of polyketide and nonribosomal peptide synthases. Curr. Opin. Chem. Biol. 1 (1997) 309–315. [DOI] [PMID: 9667867]
5.  Mootz, H.D., Finking, R. and Marahiel, M.A. 4′-Phosphopantetheine transfer in primary and secondary metabolism of Bacillus subtilis. J. Biol. Chem. 276 (2001) 37289–37298. [DOI] [PMID: 11489886]
6.  Joshi, A.K., Zhang, L., Rangan, V.S. and Smith, S. Cloning, expression, and characterization of a human 4′-phosphopantetheinyl transferase with broad substrate specificity. J. Biol. Chem. 278 (2003) 33142–33149. [DOI] [PMID: 12815048]
[EC 2.7.8.7 created 1972, modified 2006, modified 2022]
 
 
*EC 2.8.3.18
Accepted name: succinyl-CoA:acetate CoA-transferase
Reaction: succinyl-CoA + acetate = acetyl-CoA + succinate
Other name(s): aarC (gene name); SCACT
Systematic name: succinyl-CoA:acetate CoA-transferase
Comments: In some bacteria the enzyme catalyses the conversion of acetate to acetyl-CoA as part of a modified tricarboxylic acid (TCA) cycle [3,5,6]. In other organisms it converts acetyl-CoA to acetate during fermentation [1,2,4,7]. In some organisms the enzyme also catalyses the activity of EC 2.8.3.27, propanoyl-CoA:succinate CoA transferase.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Steinbuchel, A. and Muller, M. Anaerobic pyruvate metabolism of Tritrichomonas foetus and Trichomonas vaginalis hydrogenosomes. Mol. Biochem. Parasitol. 20 (1986) 57–65. [DOI] [PMID: 3090435]
2.  Sohling, B. and Gottschalk, G. Molecular analysis of the anaerobic succinate degradation pathway in Clostridium kluyveri. J. Bacteriol. 178 (1996) 871–880. [DOI] [PMID: 8550525]
3.  Mullins, E.A., Francois, J.A. and Kappock, T.J. A specialized citric acid cycle requiring succinyl-coenzyme A (CoA):acetate CoA-transferase (AarC) confers acetic acid resistance on the acidophile Acetobacter aceti. J. Bacteriol. 190 (2008) 4933–4940. [DOI] [PMID: 18502856]
4.  van Grinsven, K.W., van Hellemond, J.J. and Tielens, A.G. Acetate:succinate CoA-transferase in the anaerobic mitochondria of Fasciola hepatica. Mol. Biochem. Parasitol. 164 (2009) 74–79. [DOI] [PMID: 19103231]
5.  Mullins, E.A. and Kappock, T.J. Crystal structures of Acetobacter aceti succinyl-coenzyme A (CoA):acetate CoA-transferase reveal specificity determinants and illustrate the mechanism used by class I CoA-transferases. Biochemistry 51 (2012) 8422–8434. [DOI] [PMID: 23030530]
6.  Kwong, W.K., Zheng, H. and Moran, N.A. Convergent evolution of a modified, acetate-driven TCA cycle in bacteria. Nat Microbiol 2:17067 (2017). [DOI] [PMID: 28452983]
7.  Zhang, B., Lingga, C., Bowman, C. and Hackmann, T.J. A new pathway for forming acetate and synthesizing ATP during fermentation in bacteria. Appl. Environ. Microbiol. 87 (2021) e0295920. [DOI] [PMID: 33931420]
[EC 2.8.3.18 created 2013, modified 2022]
 
 
EC 2.8.3.27
Accepted name: propanoyl-CoA:succinate CoA transferase
Reaction: propanoyl-CoA + succinate = propanoate + succinyl-CoA
Other name(s): succinyl-CoA:propionate CoA-transferase; propionyl-CoA:succinyl-CoA transferase; ASCT; scpC (gene name)
Systematic name: propanoyl-CoA:succinate CoA transferase
Comments: The enzyme is most specific in Escherichia coli, where the preferred substrates are propanoyl-CoA and succinate. In other organisms, the enzyme uses acetyl-CoA at the same rate as propanoyl-CoA (cf. EC 2.8.3.18, succinyl-CoA:acetate CoA-transferase).
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Allen, S. H., Kellermeyer, R. W., Stjernholm, R. L., and Wood, H. G. Purification and properties of enzymes involved in the propionic acid fermentation. J. Bacteriol. 87 (1964) 171–187. [DOI] [PMID: 14102852]
2.  Schulz, T.KF. and Kluytmans, J.H. Pathway of propionate synthesis in the sea mussel Mytilus edulis L. Comp. Biochem. Physiol. B. Comp. Biochem. 75 (1983) 365–372. [DOI]
3.  Haller, T., Buckel, T., Retey, J. and Gerlt, J.A. Discovering new enzymes and metabolic pathways: conversion of succinate to propionate by Escherichia coli. Biochemistry 39 (2000) 4622–4629. [DOI] [PMID: 10769117]
4.  van Grinsven, K.W., van Hellemond, J.J. and Tielens, A.G. Acetate:succinate CoA-transferase in the anaerobic mitochondria of Fasciola hepatica. Mol. Biochem. Parasitol. 164 (2009) 74–79. [DOI] [PMID: 19103231]
5.  Zhang, B., Lingga, C., Bowman, C. and Hackmann, T.J. A new pathway for forming acetate and synthesizing ATP during fermentation in bacteria. Appl. Environ. Microbiol. 87 (2021) e0295920. [DOI] [PMID: 33931420]
[EC 2.8.3.27 created 2022]
 
 
EC 2.8.3.28
Accepted name: phenylsuccinyl-CoA transferase
Reaction: (1) phenylsuccinate + succinyl-CoA = 2-phenylsuccinyl-CoA + succinate
(2) phenylsuccinate + succinyl-CoA = 3-phenylsuccinyl-CoA + succinate
Other name(s): iaaL (gene name)
Systematic name: succinyl-CoA:2/3-phenylsuccinate CoA-transferase
Comments: The enzyme, characterized from the bacterium Aromatoleum aromaticum, is involved in degradation of (indol-3-yl)acetate, where it is believed to function on (2-aminophenyl)succinate. It has a broad substrate specificity towards other C4-dicarboxylic acids, phenylacetate, and the non-physiological compound 2-naphthylacetate. The enzyme produces 2- and 3-phenylsuccinyl-CoA in equimolar amounts. It can also perform an intramolecular transfer of the CoA moiety to convert 2-phenylsuccinyl-CoA to 3-phenylsuccinyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Schuhle, K., Nies, J. and Heider, J. An indoleacetate-CoA ligase and a phenylsuccinyl-CoA transferase involved in anaerobic metabolism of auxin. Environ. Microbiol. 18 (2016) 3120–3132. [DOI] [PMID: 27102732]
[EC 2.8.3.28 created 2022]
 
 
EC 3.1.1.119
Transferred entry: exo-acting protein-α-N-acetylgalactosaminidase. The enzyme was discovered at the public-review stage to have been misclassified and so was withdrawn. See EC 3.2.1.217, exo-acting protein-α-N-acetylgalactosaminidase.
[EC 3.1.1.119 created 2022, deleted 2022]
 
 
*EC 3.2.1.62
Accepted name: glycosylceramidase
Reaction: (1) a β-D-glucosyl-N-acylsphingosine + H2O = a ceramide + β-D-glucose
(2) a β-D-galactosyl-N-acylsphingosine + H2O = a ceramide + β-D-galactose
(3) a flavonoid-O-β-D-glucoside + H2O = a flavonoid + β-D-glucose
For diagram of phloretin biosynthesis, click here and for diagram of glycolipid biosynthesis, click here
Glossary: a ceramide = an N-acylsphingosine
Other name(s): phlorizin hydrolase; phloretin-glucosidase; glycosyl ceramide glycosylhydrolase; cerebrosidase; phloridzin β-glucosidase; lactase-phlorizin hydrolase; phloridzin glucosidase; LPH (gene name); LCT (gene name); glycosyl-N-acylsphingosine glycohydrolase
Systematic name: β-D-glucosyl-N-acylsphingosine glycohydrolase (configuration-retaining)
Comments: The enzyme, found in the intestinal mucosa, hydrolyses β-D-glucosyl and β-D-galactosyl residues from a very broad range of substrates using a retaining mechanism. Characterized substrates include glucosyl- and galactosyl-ceramides [3], O3-, O4′ and O7-glucosylated flavonoids [6], and the 2′-O-glucosylated dihydrochalcone phlorizin [1]. The enzyme includes two glycosyl hydrolase domains, both belonging to the GH1 family. While one domain is responsible for the activity described here, the other catalyses the reaction of EC 3.2.1.108, lactase [4,5]. cf. EC 3.2.1.45, glucosylceramidase and EC 3.2.1.46, galactosylceramidase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 9033-10-7
References:
1.  Malathi, P. and Crane, R.K. Phlorizin hydrolase: a β-glucosidase of hamster intestinal brush border membrane. Biochim. Biophys. Acta 173 (1969) 245–256. [DOI] [PMID: 5774775]
2.  Lorenz-Meyer, H., Blum, A.L., Haemmerli, H.P. and Semenza, G. A second enzyme defect in acquired lactase deficiency: lack of small-intestinal phlorizin-hydrolase. Eur. J. Clin. Invest. 2 (1972) 326–331. [DOI] [PMID: 5082068]
3.  Leese, H.J. and Semenza, G. On the identity between the small intestinal enzymes phlorizin hydrolase and glycosylceramidase. J. Biol. Chem. 248 (1973) 8170–8173. [DOI] [PMID: 4752949]
4.  Zecca, L., Mesonero, J.E., Stutz, A., Poiree, J.C., Giudicelli, J., Cursio, R., Gloor, S.M. and Semenza, G. Intestinal lactase-phlorizin hydrolase (LPH): the two catalytic sites; the role of the pancreas in pro-LPH maturation. FEBS Lett. 435 (1998) 225–228. [DOI] [PMID: 9762914]
5.  Arribas, J.C., Herrero, A.G., Martin-Lomas, M., Canada, F.J., He, S. and Withers, S.G. Differential mechanism-based labeling and unequivocal activity assignment of the two active sites of intestinal lactase/phlorizin hydrolase. Eur. J. Biochem. 267 (2000) 6996–7005. [DOI] [PMID: 11106409]
6.  Nemeth, K., Plumb, G.W., Berrin, J.G., Juge, N., Jacob, R., Naim, H.Y., Williamson, G., Swallow, D.M. and Kroon, P.A. Deglycosylation by small intestinal epithelial cell β-glucosidases is a critical step in the absorption and metabolism of dietary flavonoid glycosides in humans. Eur J Nutr 42 (2003) 29–42. [DOI] [PMID: 12594539]
[EC 3.2.1.62 created 1972, modified 1976, modified 2022]
 
 
*EC 3.2.1.108
Accepted name: lactase
Reaction: lactose + H2O = β-D-galactose + D-glucose
Glossary: lactose = β-D-galactopyranosyl-(1→4)-α-D-glucopyranose
Other name(s): lactase-phlorizin hydrolase; LPH (gene name); LCT (gene name)
Systematic name: lactose galactohydrolase (configuration-retaining)
Comments: The enzyme from intestinal mucosa contains two glycosyl hydrolase domains, both of which belong to glycosyl hydrolase family 1 (GH1). While the first domain catalyses the activity described here, the second domain catalyses the reaction of EC 3.2.1.62 glycosylceramidase. cf. EC 3.2.1.33 amylo-α-1,6-glucosidase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 9031-11-2
References:
1.  Asp, N.G., Dahlqvist, A. and Koldovský, O. Human small-intestinal β-galactosidases. Separation and characterization of one lactase and one hetero β-galactosidase. Biochem. J. 114 (1969) 351–359. [PMID: 5822067]
2.  Schlegel-Haueter, S., Hore, P., Kerry, K.R. and Semenza, G. The preparation of lactase and glucoamylase of rat small intestine. Biochim. Biophys. Acta 258 (1972) 506–519. [DOI] [PMID: 5010299]
3.  Lorenz-Meyer, H., Blum, A.L., Haemmerli, H.P. and Semenza, G. A second enzyme defect in acquired lactase deficiency: lack of small-intestinal phlorizin-hydrolase. Eur. J. Clin. Invest. 2 (1972) 326–331. [DOI] [PMID: 5082068]
4.  Ramaswamay, S. and Radhakrishnan, A.N. Lactase-phlorizin hydrolase complex from monkey small intestine. Purification, properties and evidence for two catalytic sites. Biochim. Biophys. Acta 403 (1975) 446–455. [DOI] [PMID: 810166]
5.  Skovbjerg, H., Sjöström, H. and Norén, O. Purification and characterization of amphiphilic lactase-phlorizin hydrolase from human small-intestine. Eur. J. Biochem. 114 (1981) 653–661. [DOI] [PMID: 6786877]
6.  Skovbjerg, H., Norén, O., Sjöström, H., Danielsen, E.M. and Enevoldsen, B.S. Further characterization of intestinal lactase/phlorizin hydrolase. Biochim. Biophys. Acta 707 (1982) 89–97. [DOI] [PMID: 6814489]
7.  Zecca, L., Mesonero, J.E., Stutz, A., Poiree, J.C., Giudicelli, J., Cursio, R., Gloor, S.M. and Semenza, G. Intestinal lactase-phlorizin hydrolase (LPH): the two catalytic sites; the role of the pancreas in pro-LPH maturation. FEBS Lett. 435 (1998) 225–228. [DOI] [PMID: 9762914]
8.  Arribas, J.C., Herrero, A.G., Martin-Lomas, M., Canada, F.J., He, S. and Withers, S.G. Differential mechanism-based labeling and unequivocal activity assignment of the two active sites of intestinal lactase/phlorizin hydrolase. Eur. J. Biochem. 267 (2000) 6996–7005. [DOI] [PMID: 11106409]
[EC 3.2.1.108 created 1984, modified 2022]
 
 
EC 3.2.1.216
Accepted name: kojibiose hydrolase
Reaction: kojibiose + H2O = β-D-glucopyranose + D-glucopyranose
Glossary: kojibiose = α-D-glucopyranosyl-(1→2)-D-glucopyranose
Other name(s): kojibiase
Systematic name: kojibiose glucohydrolase (configuration-inverting)
Comments: The enzyme, characterized from the bacteria Flavobacterium johnsoniae and Mucilaginibacter mallensis, uses anomer-inverting mechanism to release β-glucose from the non-reducing ends of kojibiose and α-1,2-oligoglucans with a higher degree of polymerization.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Nakamura, S., Nihira, T., Kurata, R., Nakai, H., Funane, K., Park, E.Y. and Miyazaki, T. Structure of a bacterial α-1,2-glucosidase defines mechanisms of hydrolysis and substrate specificity in GH65 family hydrolases. J. Biol. Chem. :101366 (2021). [DOI] [PMID: 34728215]
2.  De Beul, E., Jongbloet, A., Franceus, J. and Desmet, T. Discovery of a kojibiose hydrolase by analysis of specificity-determining correlated positions in glycoside hydrolase family 65. Molecules 26 (2021) 6321. [DOI] [PMID: 34684901]
[EC 3.2.1.216 created 2022]
 
 
EC 3.2.1.217
Accepted name: exo-acting protein-α-N-acetylgalactosaminidase
Reaction: a [protein]-N-acetyl-α-D-galactosalaminyl-(L-serine/L-threonine) + H2O = a [protein]-(L-serine/L-threonine) + N-acetyl-D-galactosamine
Other name(s): Nag31
Systematic name: [protein]-N-acetyl-α-D-galactosalaminyl-(L-serine/L-threonine) N-acetylgalactosaminohydrolase
Comments: The enzyme, which belongs to the glycosylhydrolase 31 (GH31) family, is an exo-acting α-N-acetylgalactosaminidase that acts on the innermost α-GalNAc residues at the core of O-glycans when no other saccharides are attached to it. Unlike EC 3.2.1.49, α-N-acetylgalactosaminidase, it is not able to act on blood group A antigen.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Rahfeld, P., Wardman, J.F., Mehr, K., Huff, D., Morgan-Lang, C., Chen, H.M., Hallam, S.J. and Withers, S.G. Prospecting for microbial α-N-acetylgalactosaminidases yields a new class of GH31 O-glycanase. J. Biol. Chem. 294 (2019) 16400–16415. [DOI] [PMID: 31530641]
2.  Miyazaki, T. and Park, E.Y. Crystal structure of the Enterococcus faecalis α-N-acetylgalactosaminidase, a member of the glycoside hydrolase family 31. FEBS Lett. 594 (2020) 2282–2293. [DOI] [PMID: 32367553]
3.  Ikegaya, M., Miyazaki, T. and Park, E.Y. Biochemical characterization of Bombyx mori α-N-acetylgalactosaminidase belonging to the glycoside hydrolase family 31. Insect Mol Biol 30 (2021) 367–378. [DOI] [PMID: 33742736]
4.  Miyazaki, T., Ikegaya, M. and Alonso-Gil, S. Structural and mechanistic insights into the substrate specificity and hydrolysis of GH31 α-N-acetylgalactosaminidase. Biochimie (2021) . [DOI] [PMID: 34826537]
[EC 3.2.1.217 created 2022]
 
 
*EC 3.5.4.25
Accepted name: GTP cyclohydrolase II
Reaction: GTP + 4 H2O = formate + 2,5-diamino-6-hydroxy-4-(5-phospho-D-ribosylamino)pyrimidine + 2 phosphate
For diagram of riboflavin biosynthesis (early stages), click here
Other name(s): guanosine triphosphate cyclohydrolase II; GTP-8-formylhydrolase; ribA (gene name); GTP 7,8-8,9-dihydrolase (diphosphate-forming)
Systematic name: GTP 7,8-8,9-dihydrolase (formate-releasing, phosphate-releasing)
Comments: The enzyme, found in prokaryotes and some eukaryotes, hydrolytically cleaves the C-N bond at positions 8 and 9 of GTP guanine, followed by a subsequent hydrolytic attack at the base, which liberates formate, and cleavage of the α-β phosphodiester bond of the triphosphate to form diphosphate. The enzyme continues with a slow cleavage of the diphosphate to form two phosphate ions. The enzyme requires zinc and magnesium ions for the cleavage reactions at the GTP guanine and triphosphate sites, respectively. It is one of the enzymes required for flavin biosynthesis in many bacterial species, lower eukaryotes, and plants. cf. EC 3.5.4.16, GTP cyclohydrolase I, EC 3.5.4.29, GTP cyclohydrolase IIa, and EC 3.5.4.39, GTP cyclohydrolase IV.
Links to other databases: BRENDA, EXPASY, KEGG, PDB, CAS registry number: 56214-35-8
References:
1.  Foor, F. and Brown, G.M. Purification and properties of guanosine triphosphate cyclohydrolase II from Escherichia coli. J. Biol. Chem. 250 (1975) 3545–3551. [PMID: 235552]
2.  Ritz, H., Schramek, N., Bracher, A., Herz, S., Eisenreich, W., Richter, G. and Bacher, A. Biosynthesis of riboflavin: studies on the mechanism of GTP cyclohydrolase II. J. Biol. Chem. 276 (2001) 22273–22277. [DOI] [PMID: 11301327]
3.  Schramek, N., Bracher, A. and Bacher, A. Biosynthesis of riboflavin. Single turnover kinetic analysis of GTP cyclohydrolase II. J. Biol. Chem. 276 (2001) 44157–44162. [DOI] [PMID: 11553632]
4.  Ren, J., Kotaka, M., Lockyer, M., Lamb, H.K., Hawkins, A.R. and Stammers, D.K. GTP cyclohydrolase II structure and mechanism. J. Biol. Chem. 280 (2005) 36912–36919. [DOI] [PMID: 16115872]
5.  Smith, M.M., Beaupre, B.A., Fourozesh, D.C., Meneely, K.M., Lamb, A.L. and Moran, G.R. Finding ways to relax: a revisionistic analysis of the chemistry of E. coli GTP cyclohydrolase II. Biochemistry 60 (2021) 3027–3039. [DOI] [PMID: 34569786]
[EC 3.5.4.25 created 1984, modified 2011, modified 2022]
 
 
EC 4.2.1.180
Accepted name: (E)-benzylidenesuccinyl-CoA hydratase
Reaction: (R,S)-2-(α-hydroxybenzyl)succinyl-CoA = (E)-benzylidenesuccinyl-CoA + H2O
Other name(s): bbsH (gene name)
Systematic name: (R,S)-2-(α-hydroxybenzyl)succinyl-CoA hydro-lyase
Comments: The enzyme, purified from the bacterium Thauera aromatica, is involved in an anaerobic toluene degradation pathway in which it catalyses the hydration of (E)-benzylidenesuccinyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  von Horsten, S., Lippert, M.L., Geisselbrecht, Y., Schuhle, K., Schall, I., Essen, L.O. and Heider, J. Inactive pseudoenzyme subunits in heterotetrameric BbsCD, a novel short-chain alcohol dehydrogenase involved in anaerobic toluene degradation. FEBS J. (2021) . [DOI] [PMID: 34601806]
[EC 4.2.1.180 created 2022]
 
 
*EC 5.3.1.4
Accepted name: L-arabinose isomerase
Reaction: β-L-arabinopyranose = L-ribulose
For diagram of L-Arabinose catabolism, click here
Other name(s): L-arabinose ketol-isomerase; araA (gene name)
Systematic name: β-L-arabinopyranose aldose-ketose-isomerase
Comments: Requires a divalent metal ion (the enzyme from the bacterium Escherichia coli prefers Mn2+) [2]. The enzyme binds β-L-arabinopyranose [4] and catalyses ring opening to generate a form of open-chain conformation that facilitates the isomerization reaction, which proceeds via an ene-diol mechanism [6]. The enzyme can also convert α-D-galactose to D-tagatose with lower efficiency [5].
Links to other databases: BRENDA, EXPASY, GTD, KEGG, PDB, CAS registry number: 9023-80-7
References:
1.  Heath, E.C., Horecker, B.L., Smyrniotis, P.Z. and Takagi, Y. Pentose formation by Lactobacillus plantarum. II. L-Arabinose isomerase. J. Biol. Chem. 231 (1958) 1031–1037. [PMID: 13539034]
2.  Patrick, J.W. and Lee, N. Purification and properties of an L-arabinose isomerase from Escherichia coli. J. Biol. Chem. 243 (1968) 4312–4318. [PMID: 4878429]
3.  Nakamatu, T. and Yamanaka, K. Crystallization and properties of L-arabinose isomerase from Lactobacillus gayonii. Biochim. Biophys. Acta 178 (1969) 156–165. [DOI] [PMID: 5773448]
4.  Schray, K.J. and Rose, I.A. Anomeric specificity and mechanism of two pentose isomerases. Biochemistry 10 (1971) 1058–1062. [DOI] [PMID: 5550812]
5.  Cheetham, P.S.J. and Wootton, A.N. Bioconversion of D-galactose into D-tagatose. Enzyme and Microbial Technology 15 (1993) 105–108.
6.  Banerjee, S., Anderson, F. and Farber, G.K. The evolution of sugar isomerases. Protein Eng. 8 (1995) 1189–1195. [DOI] [PMID: 8869631]
7.  Manjasetty, B.A. and Chance, M.R. Crystal structure of Escherichia coli L-arabinose isomerase (ECAI), the putative target of biological tagatose production. J. Mol. Biol. 360 (2006) 297–309. [DOI] [PMID: 16756997]
[EC 5.3.1.4 created 1961, modified 2022]
 
 
*EC 5.3.1.5
Accepted name: xylose isomerase
Reaction: α-D-xylopyranose = α-D-xylulofuranose
Other name(s): D-xylose isomerase; D-xylose ketoisomerase; D-xylose ketol-isomerase; D-xylose aldose-ketose-isomerase
Systematic name: α-D-xylopyranose aldose-ketose-isomerase
Comments: Contains two divalent metal ions, preferably magnesium, located at different metal-binding sites within the active site. The enzyme catalyses the interconversion of aldose and ketose sugars with broad substrate specificity. The enzyme binds the closed form of its sugar substrate (in the case of xylose and glucose, only the α anomer [4]) and catalyses ring opening to generate a form of open-chain conformation that is coordinated to one of the metal sites. Isomerization proceeds via a hydride-shift mechanism.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, PDB, CAS registry number: 9023-82-9
References:
1.  Hochster, R.M. and Watson, R.W. Enzymatic isomerization of D-xylose to D-xylulose. Arch. Biochem. Biophys. 48 (1954) 120–129. [DOI] [PMID: 13125579]
2.  Slein, M.W. Xylose isomerase from Pasteurella pestis, strain A-1122. J. Am. Chem. Soc. 77 (1955) 1663–1667. [DOI]
3.  Yamanaka, K. Purification, crystallization and properties of the D-xylose isomerase from Lactobacillus brevis. Biochim. Biophys. Acta 151 (1968) 670–680. [DOI] [PMID: 5646045]
4.  Schray, K.J. and Rose, I.A. Anomeric specificity and mechanism of two pentose isomerases. Biochemistry 10 (1971) 1058–1062. [DOI] [PMID: 5550812]
5.  Carrell, H.L., Glusker, J.P., Burger, V., Manfre, F., Tritsch, D. and Biellmann, J.F. X-ray analysis of D-xylose isomerase at 1.9 Å: native enzyme in complex with substrate and with a mechanism-designed inactivator. Proc. Natl. Acad. Sci. USA 86 (1989) 4440–4444. [DOI] [PMID: 2734296]
6.  Collyer, C.A. and Blow, D.M. Observations of reaction intermediates and the mechanism of aldose-ketose interconversion by D-xylose isomerase. Proc. Natl. Acad. Sci. USA 87 (1990) 1362–1366. [DOI] [PMID: 2304904]
7.  Whitlow, M., Howard, A.J., Finzel, B.C., Poulos, T.L., Winborne, E. and Gilliland, G.L. A metal-mediated hydride shift mechanism for xylose isomerase based on the 1.6 Å Streptomyces rubiginosus structures with xylitol and D-xylose. Proteins 9 (1991) 153–173. [DOI] [PMID: 2006134]
8.  Allen, K.N., Lavie, A., Glasfeld, A., Tanada, T.N., Gerrity, D.P., Carlson, S.C., Farber, G.K., Petsko, G.A. and Ringe, D. Role of the divalent metal ion in sugar binding, ring opening, and isomerization by D-xylose isomerase: replacement of a catalytic metal by an amino acid. Biochemistry 33 (1994) 1488–1494. [DOI] [PMID: 7906142]
[EC 5.3.1.5 created 1961 (EC 5.3.1.18 created 1972, part incorporated 1978), modified 2022]
 
 
EC 6.2.1.75
Accepted name: indoleacetate—CoA ligase
Reaction: ATP + (indol-3-yl)acetate + CoA = AMP + diphosphate + (indol-3-yl)acetyl-CoA
Other name(s): iaaB (gene name)
Systematic name: (indol-3-yl)acetate:CoA ligase (AMP-forming)
Comments: The enzyme, characterized from the bacterium Aromatoleum aromaticum, is involved in degradation of (indol-3-yl)acetate. It is also active with phenylacetate and the non-physiological compound (2-naphthyl)acetate.
Links to other databases: BRENDA, EXPASY, KEGG
References:
1.  Schuhle, K., Nies, J. and Heider, J. An indoleacetate-CoA ligase and a phenylsuccinyl-CoA transferase involved in anaerobic metabolism of auxin. Environ. Microbiol. 18 (2016) 3120–3132. [DOI] [PMID: 27102732]
[EC 6.2.1.75 created 2022]
 
 


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