The Enzyme Database

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EC 4.2.1.155     Relevance: 100%
Accepted name: (methylthio)acryloyl-CoA hydratase
Reaction: 3-(methylsulfanyl)acryloyl-CoA + 2 H2O = acetaldehyde + methanethiol + CoA + CO2 (overall reaction)
(1a) 3-(methylsulfanyl)acryloyl-CoA + H2O = 3-hydroxy-3-(methylsulfanyl)propanoyl-CoA
(1b) 3-hydroxy-3-(methylsulfanyl)propanoyl-CoA = 3-oxopropanoyl-CoA + methanethiol
(1c) 3-oxopropanoyl-CoA + H2O = 3-oxopropanoate + CoA
(1d) 3-oxopropanoate = acetaldehyde + CO2
Glossary: 3-(methylsulfanyl)acryloyl-CoA = 3-(methylsulfanyl)prop-2-enoyl-CoA
Other name(s): DmdD
Systematic name: 3-(methylsulfanyl)prop-2-enoyl-CoA hydro-lyase (acetaldehyde-forming)
Comments: The enzyme is involved in the degradation of 3-(dimethylsulfonio)propanoate, an osmolyte produced by marine phytoplankton. Isolated from the bacterium Ruegeria pomeroyi.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Tan, D., Crabb, W.M., Whitman, W.B. and Tong, L. Crystal structure of DmdD, a crotonase superfamily enzyme that catalyzes the hydration and hydrolysis of methylthioacryloyl-CoA. PLoS One 8:e63870 (2013). [DOI] [PMID: 23704947]
[EC 4.2.1.155 created 2015]
 
 
EC 2.8.3.17     Relevance: 62.5%
Accepted name: 3-(aryl)acryloyl-CoA:(R)-3-(aryl)lactate CoA-transferase
Reaction: (1) (E)-cinnamoyl-CoA + (R)-(phenyl)lactate = (E)-cinnamate + (R)-(phenyl)lactoyl-CoA
(2) (E)-4-coumaroyl-CoA + (R)-3-(4-hydroxyphenyl)lactate = 4-coumarate + (R)-3-(4-hydroxyphenyl)lactoyl-CoA
(3) 3-(indol-3-yl)acryloyl-CoA + (R)-3-(indol-3-yl)lactate = 3-(indol-3-yl)acrylate + (R)-3-(indol-3-yl)lactoyl-CoA
Other name(s): FldA; cinnamoyl-CoA:phenyllactate CoA-transferase
Systematic name: 3-(aryl)acryloyl-CoA:(R)-3-(aryl)lactate CoA-transferase
Comments: The enzyme, found in some amino acid-fermenting anaerobic bacteria, participates in the fermentation pathways of L-phenylalanine, L-tyrosine, and L-tryptophan. It forms a complex with EC 4.2.1.175, (R)-3-(aryl)lactoyl-CoA dehydratase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 289682-21-9
References:
1.  Dickert, S., Pierik, A.J., Linder, D. and Buckel, W. The involvement of coenzyme A esters in the dehydration of (R)-phenyllactate to (E)-cinnamate by Clostridium sporogenes. Eur. J. Biochem. 267 (2000) 3874–3884. [DOI] [PMID: 10849007]
2.  Dodd, D., Spitzer, M.H., Van Treuren, W., Merrill, B.D., Hryckowian, A.J., Higginbottom, S.K., Le, A., Cowan, T.M., Nolan, G.P., Fischbach, M.A. and Sonnenburg, J.L. A gut bacterial pathway metabolizes aromatic amino acids into nine circulating metabolites. Nature 551 (2017) 648–652. [PMID: 29168502]
[EC 2.8.3.17 created 2003, modified 2019]
 
 
EC 4.2.1.54     Relevance: 56.2%
Accepted name: lactoyl-CoA dehydratase
Reaction: (R)-lactoyl-CoA = acryloyl-CoA + H2O
Other name(s): lactoyl coenzyme A dehydratase; lactyl-coenzyme A dehydrase; lactyl CoA dehydratase; acrylyl coenzyme A hydratase; lactoyl-CoA hydro-lyase
Systematic name: (R)-lactoyl-CoA hydro-lyase (acryloyl-CoA-forming)
Comments: A bacterial enzyme that is involved in propanoate fermentation (also known as the acrylate pathway).
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, CAS registry number: 9031-12-3
References:
1.  Baldwin, R.L., Wood, W.A. and Emery, R.S. Lactate metabolism by Peptostreptococcus elsdenii: evidence for lactyl coenzyme a dehydrase. Biochim. Biophys. Acta 97 (1965) 202–213. [DOI] [PMID: 14292829]
2.  Schweiger, G. and Buckel, W. On the dehydration of (R)-lactate in the fermentation of alanine to propionate by Clostridium propionicum. FEBS Lett. 171 (1984) 79–84. [DOI] [PMID: 6586495]
3.  Kuchta, R.D. and Abeles, R.H. Lactate reduction in Clostridium propionicum. Purification and properties of lactyl-CoA dehydratase. J. Biol. Chem. 260 (1985) 13181–13189. [PMID: 4055736]
4.  Kuchta, R.D., Hanson, G.R., Holmquist, B. and Abeles, R.H. Fe-S centers in lactyl-CoA dehydratase. Biochemistry 25 (1986) 7301–7307. [PMID: 3026450]
5.  Hofmeister, A.E. and Buckel, W. (R)-Lactyl-CoA dehydratase from Clostridium propionicum. Stereochemistry of the dehydration of (R)-2-hydroxybutyryl-CoA to crotonyl-CoA. Eur. J. Biochem. 206 (1992) 547–552. [DOI] [PMID: 1597194]
[EC 4.2.1.54 created 1972, modified 2012]
 
 
EC 4.3.1.6     Relevance: 55.8%
Accepted name: β-alanyl-CoA ammonia-lyase
Reaction: β-alanyl-CoA = acryloyl-CoA + NH3
Other name(s): β-alanyl coenzyme A ammonia-lyase
Systematic name: β-alanyl-CoA ammonia-lyase (acryloyl-CoA-forming)
Comments: The reaction has only been demonstrated in the direction of addition of ammonia.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, CAS registry number: 9024-29-7
References:
1.  Stadtman, E.R. The enzymic synthesis of β-alanyl coenzyme A. J. Am. Chem. Soc. 77 (1955) 5765–5766.
[EC 4.3.1.6 created 1965]
 
 
EC 1.1.1.428     Relevance: 52.4%
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, MetaCyc
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 1.3.1.84     Relevance: 50%
Accepted name: acrylyl-CoA reductase (NADPH)
Reaction: propanoyl-CoA + NADP+ = acryloyl-CoA + NADPH + H+
For diagram of the 3-hydroxypropanoate cycle, click here, for diagram of the 3-hydroxypropanoate/4-hydroxybutanoate cycle and dicarboxylate/4-hydroxybutanoate cycle in archaea, click here and for diagram of 3-(dimethylsulfonio)propanoate met
Glossary: propanoyl-CoA = propionyl-CoA
acryloyl-CoA = acrylyl-CoA = propenoyl-CoA
Systematic name: propanoyl-CoA:NADP+ oxidoreductase
Comments: Catalyses a step in the 3-hydroxypropanoate/4-hydroxybutanoate cycle, an autotrophic CO2 fixation pathway found in some thermoacidophilic archaea [1]. The enzyme from Sulfolobus tokodaii does not act on either NADH or crotonyl-CoA [2]. Different from EC 1.3.1.8, which acts only on enoyl-CoA derivatives of carbon chain length 4 to 16. Contains Zn2+.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Berg, I.A., Kockelkorn, D., Buckel, W. and Fuchs, G. A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea. Science 318 (2007) 1782–1786. [DOI] [PMID: 18079405]
2.  Teufel, R., Kung, J.W., Kockelkorn, D., Alber, B.E. and Fuchs, G. 3-hydroxypropionyl-coenzyme A dehydratase and acryloyl-coenzyme A reductase, enzymes of the autotrophic 3-hydroxypropionate/4-hydroxybutyrate cycle in the Sulfolobales. J. Bacteriol. 191 (2009) 4572–4581. [DOI] [PMID: 19429610]
[EC 1.3.1.84 created 2009, modified 2014]
 
 
EC 4.2.1.116     Relevance: 49%
Accepted name: 3-hydroxypropionyl-CoA dehydratase
Reaction: 3-hydroxypropanoyl-CoA = acryloyl-CoA + H2O
For diagram of the 3-hydroxypropanoate cycle, click here and for diagram of the 3-hydroxypropanoate/4-hydroxybutanoate cycle and dicarboxylate/4-hydroxybutanoate cycle in archaea, click here
Glossary: acryloyl-CoA = acrylyl-CoA
3-hydroxypropanoyl-CoA = 3-hydroxypropionyl-CoA
Other name(s): 3-hydroxypropionyl-CoA hydro-lyase; 3-hydroxypropanoyl-CoA dehydratase
Systematic name: 3-hydroxypropanoyl-CoA hydro-lyase
Comments: Catalyses a step in the 3-hydroxypropanoate/4-hydroxybutanoate cycle, an autotrophic CO2 fixation pathway found in some thermoacidophilic archaea [1]. The enzyme from Metallosphaera sedula acts nearly equally as well on (S)-3-hydroxybutanoyl-CoA but not (R)-3-hydroxybutanoyl-CoA [2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Berg, I.A., Kockelkorn, D., Buckel, W. and Fuchs, G. A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea. Science 318 (2007) 1782–1786. [DOI] [PMID: 18079405]
2.  Teufel, R., Kung, J.W., Kockelkorn, D., Alber, B.E. and Fuchs, G. 3-hydroxypropionyl-coenzyme A dehydratase and acryloyl-coenzyme A reductase, enzymes of the autotrophic 3-hydroxypropionate/4-hydroxybutyrate cycle in the Sulfolobales. J. Bacteriol. 191 (2009) 4572–4581. [DOI] [PMID: 19429610]
[EC 4.2.1.116 created 2009]
 
 
EC 6.2.1.44     Relevance: 47.1%
Accepted name: 3-(methylthio)propionyl—CoA ligase
Reaction: ATP + 3-(methylsulfanyl)propanoate + CoA = AMP + diphosphate + 3-(methylsulfanyl)propanoyl-CoA
For diagram of 3-(dimethylsulfonio)propanoate metabolism, click here
Other name(s): DmdB; MMPA-CoA ligase; methylmercaptopropionate-coenzyme A ligase; 3-methylmercaptopropionyl-CoA ligase; 3-(methylthio)propanoate:CoA ligase (AMP-forming)
Systematic name: 3-(methylsulfanyl)propanoate:CoA ligase (AMP-forming)
Comments: The enzyme is part of a dimethylsulfoniopropanoate demethylation pathway in the marine bacteria Ruegeria pomeroyi and Pelagibacter ubique. It also occurs in some nonmarine bacteria capable of metabolizing dimethylsulfoniopropionate (e.g. Burkholderia thailandensis, Pseudomonas aeruginosa, and Silicibacter lacuscaerulensis). It requires Mg2+ [2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
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., Reisch, C.R., Burns, A.S., Moran, M.A. and Whitman, W.B. Regulatory and functional diversity of methylmercaptopropionate coenzyme A ligases from the dimethylsulfoniopropionate demethylation pathway in Ruegeria pomeroyi DSS-3 and other proteobacteria. J. Bacteriol. 196 (2014) 1275–1285. [DOI] [PMID: 24443527]
[EC 6.2.1.44 created 2014]
 
 
EC 4.2.1.170     Relevance: 45.7%
Accepted name: 2-(ω-methylthio)alkylmalate dehydratase
Reaction: (1) a 2-[(ω-methylsulfanyl)alkyl]malate = a 2-[(ω-methylsulfanyl)alkyl]maleate + H2O
(2) a 3-[(ω-methylsulfanyl)alkyl]malate = a 2-[(ω-methylsulfanyl)alkyl]maleate + H2O
For diagram of L-Homomethionine biosynthesis, click here
Other name(s): IPMI (gene name); 2-[(ω-methylthio)alkyl]malate hydro-lyase (2-[(ω-methylthio)alkyl]maleate-forming)
Systematic name: 2-[(ω-methylsulfanyl)alkyl]malate hydro-lyase (2-[(ω-methylsulfanyl)alkyl]maleate-forming)
Comments: The enzyme, characterized from the plant Arabidopsis thaliana, is involved in the L-methionine side-chain elongation pathway, forming substrates for the biosynthesis of aliphatic glucosinolates. By catalysing a dehydration of a 2-[(ω-methylsulfanyl)alkyl]maleate, followed by a hydration at a different position, the enzyme achieves the isomerization of its substrates. The enzyme is a heterodimer comprising a large and a small subunits. The large subunit can also bind to an alternative small subunit, forming EC 4.2.1.33, 3-isopropylmalate dehydratase, which participates in L-leucine biosynthesis.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Knill, T., Reichelt, M., Paetz, C., Gershenzon, J. and Binder, S. Arabidopsis thaliana encodes a bacterial-type heterodimeric isopropylmalate isomerase involved in both Leu biosynthesis and the Met chain elongation pathway of glucosinolate formation. Plant Mol. Biol. 71 (2009) 227–239. [DOI] [PMID: 19597944]
[EC 4.2.1.170 created 2016]
 
 
EC 1.14.13.237     Relevance: 43.9%
Accepted name: aliphatic glucosinolate S-oxygenase
Reaction: an ω-(methylsulfanyl)alkyl-glucosinolate + NADPH + H+ + O2 = an ω-(methylsulfinyl)alkyl-glucosinolate + NADP+ + H2O
Glossary: ω-(methylsulfanyl)alkyl-glucosinolate = an ω-(methylsulfanyl)-N-sulfo-alkylhydroximate S-glucoside
Other name(s): ω-(methylthio)alkylglucosinolate S-oxygenase; GS-OX1 (gene name); ω-(methylthio)alkyl-glucosinolate,NADPH:oxygen S-oxidoreductase
Systematic name: ω-(methylsulfanyl)alkyl-glucosinolate,NADPH:oxygen S-oxidoreductase
Comments: The enzyme is a member of the flavin-dependent monooxygenase (FMO) family (cf. EC 1.14.13.8). The plant Arabidopsis thaliana contains five isoforms. GS-OX1 through GS-OX4 are able to catalyse the S-oxygenation independent of chain length, while GS-OX5 is specific for 8-(methylsulfanyl)octyl glucosinolate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Hansen, B.G., Kliebenstein, D.J. and Halkier, B.A. Identification of a flavin-monooxygenase as the S-oxygenating enzyme in aliphatic glucosinolate biosynthesis in Arabidopsis. Plant J. 50 (2007) 902–910. [DOI] [PMID: 17461789]
2.  Li, J., Hansen, B.G., Ober, J.A., Kliebenstein, D.J. and Halkier, B.A. Subclade of flavin-monooxygenases involved in aliphatic glucosinolate biosynthesis. Plant Physiol. 148 (2008) 1721–1733. [DOI] [PMID: 18799661]
[EC 1.14.13.237 created 2017]
 
 
EC 4.2.1.175     Relevance: 42.3%
Accepted name: (R)-3-(aryl)lactoyl-CoA dehydratase
Reaction: (1) (R)-3-(phenyl)lactoyl-CoA = (E)-cinnamoyl-CoA + H2O
(2) (R)-3-(4-hydroxyphenyl)lactoyl-CoA = (E)-4-coumaroyl-CoA + H2O
(3) (R)-3-(indol-3-yl)lactoyl-CoA = 3-(indol-3-yl)acryloyl-CoA + H2O
Other name(s): fldBC (gene names); (R)-phenyllactoyl-CoA dehydratase; aryllactyl-CoA dehydratase
Systematic name: (R)-3-(aryl)lactoyl-CoA hydro-lyase
Comments: The enzyme, found in some amino acid-fermenting anaerobic bacteria, participates in the fermentation pathways of L-phenylalanine, L-tyrosine, and L-tryptophan. It is a heterodimeric protein consisting of the FldB and FldC polypeptides, both of which contain an [4Fe-4S] cluster, and forms a complex with EC 2.8.3.17, 3-(aryl)acryloyl-CoA:(R)-3-(aryl)lactate CoA-transferase (FldA). In order to catalyse the reaction, the enzyme requires one high-energy electron that transiently reduces the electrophilic thiol ester carbonyl of the substrate to a nucleophilic ketyl radical anion, facilitating the elimination of the hydroxyl group. This electron, which is provided by by EC 5.6.1.9, (R)-2-hydroxyacyl-CoA dehydratase activating ATPase, needs to be supplied only once, before the first reaction takes place, as it is regenerated at the end of each reaction cycle. The enzyme acts on (R)-3-(aryl)lactoyl-CoAs produced by FldA, and regenerates the CoA donors used by that enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Dickert, S., Pierik, A.J., Linder, D. and Buckel, W. The involvement of coenzyme A esters in the dehydration of (R)-phenyllactate to (E)-cinnamate by Clostridium sporogenes. Eur. J. Biochem. 267 (2000) 3874–3884. [DOI] [PMID: 10849007]
2.  Dickert, S., Pierik, A.J. and Buckel, W. Molecular characterization of phenyllactate dehydratase and its initiator from Clostridium sporogenes. Mol. Microbiol. 44 (2002) 49–60. [PMID: 11967068]
3.  Kim, J., Hetzel, M., Boiangiu, C.D. and Buckel, W. Dehydration of (R)-2-hydroxyacyl-CoA to enoyl-CoA in the fermentation of α-amino acids by anaerobic bacteria. FEMS Microbiol. Rev. 28 (2004) 455–468. [PMID: 15374661]
4.  Kim, J., Darley, D.J., Buckel, W. and Pierik, A.J. An allylic ketyl radical intermediate in clostridial amino-acid fermentation. Nature 452 (2008) 239–242. [PMID: 18337824]
5.  Dodd, D., Spitzer, M.H., Van Treuren, W., Merrill, B.D., Hryckowian, A.J., Higginbottom, S.K., Le, A., Cowan, T.M., Nolan, G.P., Fischbach, M.A. and Sonnenburg, J.L. A gut bacterial pathway metabolizes aromatic amino acids into nine circulating metabolites. Nature 551 (2017) 648–652. [PMID: 29168502]
[EC 4.2.1.175 created 2019]
 
 
EC 2.3.1.126     Relevance: 35.8%
Accepted name: isocitrate O-dihydroxycinnamoyltransferase
Reaction: caffeoyl-CoA + isocitrate = CoA + 2-O-caffeoylisocitrate
Glossary: 2-O-caffeoylisocitrate = (1R,2S)-1-{[3-(E)-(3,4-dihydroxyphenyl)acryloyl]oxy}propane-1,2,3-tricarboxylate = (3S,4R)-3-carboxy-2,3-dideoxy-4-O-[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]pentarate
isocitrate = (1R,2S)-1-hydroxypropane-1,2,3-tricarboxylate = threo-Ds-isocitrate
Systematic name: caffeoyl-CoA:isocitrate 2-O-(3,4-dihydroxycinnamoyl)transferase
Comments: Feruloyl-CoA and 4-coumaroyl-CoA can also act as donors.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 112352-88-2
References:
1.  Strack, D., Leicht, P., Bokern, M., Wray, V. and Grotjahn, L. Hydroxycinnamic acid-esters of isocitric acid - accumulation and enzymatic-synthesis in Amaranthus cruentus. Phytochemistry 26 (1987) 2919–2922.
[EC 2.3.1.126 created 1990]
 
 
EC 1.3.99.41     Relevance: 35%
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, MetaCyc
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 1.14.14.43     Relevance: 33.4%
Accepted name: (methylsulfanyl)alkanaldoxime N-monooxygenase
Reaction: an (E)-ω-(methylsulfanyl)alkanal oxime + [reduced NADPH—hemoprotein reductase] + glutathione + O2 = an S-[(1E)-1-(hydroxyimino)-ω-(methylsulfanyl)alkyl]-L-glutathione + [oxidized NADPH—hemoprotein reductase] + 2 H2O (overall reaction)
(1a) an (E)-ω-(methylsulfanyl)alkanal oxime + [reduced NADPH—hemoprotein reductase] + O2 = a 1-(methylsulfanyl)-4-aci-nitroalkane + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) a 1-(methylsulfanyl)-4-aci-nitroalkane + glutathione = an S-[(1E)-1-(hydroxyimino)-ω-(methylsulfanyl)alkyl]-L-glutathione + H2O
Glossary: a 1-(methylsulfanyl)-4-aci-nitroalkane = a hydroxyoxo-λ5-azanylidene-ω-(methylsulfanyl)alkane
Other name(s): CYP83A1 (gene name); (methylthio)alkanaldoxime N-monooxygenase; (E)-ω-(methylthio)alkananaldoxime,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (N-hydroxylating)
Systematic name: (E)-ω-(methylsulfanyl)alkananal oxime,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (N-hydroxylating)
Comments: This cytochrome P-450 (heme thiolate) enzyme is involved in the biosynthesis of glucosinolates in plants. The enzyme catalyses an N-hydroxylation of the E isomer of ω-(methylsulfanyl)alkanal oximes, forming an aci-nitro intermediate that reacts non-enzymically with glutathione to produce an N-alkyl-thiohydroximate adduct, the committed precursor of glucosinolates. In the absence of a thiol compound, the enzyme is suicidal, probably due to interaction of the reactive aci-nitro intermediate with active site residues.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Bak, S., Tax, F.E., Feldmann, K.A., Galbraith, D.W. and Feyereisen, R. CYP83B1, a cytochrome P450 at the metabolic branch point in auxin and indole glucosinolate biosynthesis in Arabidopsis. Plant Cell 13 (2001) 101–111. [PMID: 11158532]
2.  Naur, P., Petersen, B.L., Mikkelsen, M.D., Bak, S., Rasmussen, H., Olsen, C.E. and Halkier, B.A. CYP83A1 and CYP83B1, two nonredundant cytochrome P450 enzymes metabolizing oximes in the biosynthesis of glucosinolates in Arabidopsis. Plant Physiol. 133 (2003) 63–72. [DOI] [PMID: 12970475]
3.  Clausen, M., Kannangara, R.M., Olsen, C.E., Blomstedt, C.K., Gleadow, R.M., Jørgensen, K., Bak, S., Motawie, M.S. and Møller, B.L. The bifurcation of the cyanogenic glucoside and glucosinolate biosynthetic pathways. Plant J. 84 (2015) 558–573. [DOI] [PMID: 26361733]
[EC 1.14.14.43 created 2017]
 
 
EC 1.3.1.95     Relevance: 33.2%
Accepted name: acrylyl-CoA reductase (NADH)
Reaction: propanoyl-CoA + NAD+ = acryloyl-CoA + NADH + H+
For diagram of 3-(dimethylsulfonio)propanoate metabolism, click here
Glossary: propanoyl-CoA = propionyl-CoA
Systematic name: propanoyl-CoA:NAD+ oxidoreductase
Comments: Contains FAD. The reaction is catalysed in the opposite direction to that shown. The enzyme from the bacterium Clostridium propionicum is a complex that includes an electron-transfer flavoprotein (ETF). The ETF is reduced by NADH and transfers the electrons to the active site. Catalyses a step in a pathway for L-alanine fermentation to propanoate [1]. cf. EC 1.3.1.84, acrylyl-CoA reductase (NADPH).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Hetzel, M., Brock, M., Selmer, T., Pierik, A.J., Golding, B.T. and Buckel, W. Acryloyl-CoA reductase from Clostridium propionicum. An enzyme complex of propionyl-CoA dehydrogenase and electron-transferring flavoprotein. Eur. J. Biochem. 270 (2003) 902–910. [DOI] [PMID: 12603323]
2.  Kandasamy, V., Vaidyanathan, H., Djurdjevic, I., Jayamani, E., Ramachandran, K.B., Buckel, W., Jayaraman, G. and Ramalingam, S. Engineering Escherichia coli with acrylate pathway genes for propionic acid synthesis and its impact on mixed-acid fermentation. Appl. Microbiol. Biotechnol. 97 (2013) 1191–1200. [DOI] [PMID: 22810300]
[EC 1.3.1.95 created 2012]
 
 
EC 2.8.4.3     Relevance: 32.4%
Accepted name: tRNA-2-methylthio-N6-dimethylallyladenosine synthase
Reaction: N6-(3-methylbut-2-en-1-yl)-adenine37 in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine + reduced electron acceptor = N6-(3-methylbut-2-en-1-yl)-2-(methylsulfanyl)adenine37 in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5′-deoxyadenine + electron acceptor (overall reaction)
(1a) N6-(3-methylbut-2-en-1-yl)-adenine37 in tRNA + sulfur-(sulfur carrier) + S-adenosyl-L-methionine + reduced electron acceptor = N6-(3-methylbut-2-en-1-yl)-2-thioadenine37 in tRNA + (sulfur carrier) + L-methionine + 5′-deoxyadenine + electron acceptor
(1b) S-adenosyl-L-methionine + N6-(3-methylbut-2-en-1-yl)-2-thioadenine37 in tRNA = S-adenosyl-L-homocysteine + N6-(3-methylbut-2-en-1-yl)-2-(methylsulfanyl)adenine37 in tRNA
For diagram of N6-(dimethylallyl)adenosine37 modified tRNA biosynthesis, click here
Glossary: N6-(3-methylbut-2-en-1-yl)-adenine37 in tRNA = N6-dimethylallyladenine37 in tRNA
Other name(s): MiaB; 2-methylthio-N-6-isopentenyl adenosine synthase; tRNA-i6A37 methylthiotransferase; tRNA (N6-dimethylallyladenosine37):sulfur-(sulfur carrier),S-adenosyl-L-methionine C2-methylthiotransferase
Systematic name: tRNA N6-(3-methylbut-2-en-1-yl)-adenine37:sulfur-(sulfur carrier),S-adenosyl-L-methionine C2-(methylsulfanyl)transferase
Comments: This bacterial enzyme binds two [4Fe-4S] clusters as well as the transferred sulfur [3]. The enzyme is a member of the superfamily of S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes. The sulfur donor is believed to be one of the [4Fe-4S] clusters, which is sacrificed in the process, so that in vitro the reaction is a single turnover. The identity of the electron donor is not known.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Pierrel, F., Bjork, G.R., Fontecave, M. and Atta, M. Enzymatic modification of tRNAs: MiaB is an iron-sulfur protein. J. Biol. Chem. 277 (2002) 13367–13370. [DOI] [PMID: 11882645]
2.  Pierrel, F., Hernandez, H.L., Johnson, M.K., Fontecave, M. and Atta, M. MiaB protein from Thermotoga maritima. Characterization of an extremely thermophilic tRNA-methylthiotransferase. J. Biol. Chem. 278 (2003) 29515–29524. [DOI] [PMID: 12766153]
3.  Pierrel, F., Douki, T., Fontecave, M. and Atta, M. MiaB protein is a bifunctional radical-S-adenosylmethionine enzyme involved in thiolation and methylation of tRNA. J. Biol. Chem. 279 (2004) 47555–47563. [DOI] [PMID: 15339930]
4.  Hernandez, H.L., Pierrel, F., Elleingand, E., Garcia-Serres, R., Huynh, B.H., Johnson, M.K., Fontecave, M. and Atta, M. MiaB, a bifunctional radical-S-adenosylmethionine enzyme involved in the thiolation and methylation of tRNA, contains two essential [4Fe-4S] clusters. Biochemistry 46 (2007) 5140–5147. [DOI] [PMID: 17407324]
5.  Landgraf, B.J., Arcinas, A.J., Lee, K.H. and Booker, S.J. Identification of an intermediate methyl carrier in the radical S-adenosylmethionine methylthiotransferases RimO and MiaB. J. Am. Chem. Soc. 135 (2013) 15404–15416. [DOI] [PMID: 23991893]
[EC 2.8.4.3 created 2014, modified 2015]
 
 
EC 2.5.1.79     Relevance: 27.6%
Accepted name: thermospermine synthase
Reaction: S-adenosyl 3-(methylsulfanyl)propylamine + spermidine = S-methyl-5′-thioadenosine + thermospermine + H+
Glossary: thermospermine = N1-[3-(3-aminopropylamino)propyl]butane-1,4-diamine
S-adenosyl 3-(methylsulfanyl)propylamine = (3-aminopropyl){[(2S,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl}methylsulfonium
Other name(s): TSPMS; ACL5; SAC51; S-adenosyl 3-(methylthio)propylamine:spermidine 3-aminopropyltransferase (thermospermine synthesizing)
Systematic name: S-adenosyl 3-(methylsulfanyl)propylamine:spermidine 3-aminopropyltransferase (thermospermine-forming)
Comments: This plant enzyme is crucial for the proper functioning of xylem vessel elements in the vascular tissues of plants [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Romer, P., Faltermeier, A., Mertins, V., Gedrange, T., Mai, R. and Proff, P. Investigations about N-aminopropyl transferases probably involved in biomineralization. J. Physiol. Pharmacol. 59 Suppl 5 (2008) 27–37. [PMID: 19075322]
2.  Knott, J.M., Romer, P. and Sumper, M. Putative spermine synthases from Thalassiosira pseudonana and Arabidopsis thaliana synthesize thermospermine rather than spermine. FEBS Lett. 581 (2007) 3081–3086. [DOI] [PMID: 17560575]
3.  Muniz, L., Minguet, E.G., Singh, S.K., Pesquet, E., Vera-Sirera, F., Moreau-Courtois, C.L., Carbonell, J., Blazquez, M.A. and Tuominen, H. ACAULIS5 controls Arabidopsis xylem specification through the prevention of premature cell death. Development 135 (2008) 2573–2582. [DOI] [PMID: 18599510]
[EC 2.5.1.79 created 2010, modified 2013]
 
 
EC 3.1.3.87     Relevance: 26.9%
Accepted name: 2-hydroxy-3-keto-5-methylthiopentenyl-1-phosphate phosphatase
Reaction: 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-en-1-yl phosphate + H2O = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + phosphate
Other name(s): HK-MTPenyl-1-P phosphatase; MtnX; YkrX; 2-hydroxy-5-(methylthio)-3-oxopent-1-enyl phosphate phosphohydrolase; 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate phosphohydrolase
Systematic name: 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-en-1-yl phosphate phosphohydrolase
Comments: The enzyme participates in the methionine salvage pathway in Bacillus subtilis [2]. In some species a single bifunctional enzyme, EC 3.1.3.77, acireductone synthase, catalyses both this reaction and EC 5.3.2.5, 2,3-diketo-5-methylthiopentyl-1-phosphate enolase [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Myers, R.W., Wray, J.W., Fish, S. and Abeles, R.H. Purification and characterization of an enzyme involved in oxidative carbon-carbon bond cleavage reactions in the methionine salvage pathway of Klebsiella pneumoniae. J. Biol. Chem. 268 (1993) 24785–24791. [PMID: 8227039]
2.  Ashida, H., Saito, Y., Kojima, C., Kobayashi, K., Ogasawara, N. and Yokota, A. A functional link between RuBisCO-like protein of Bacillus and photosynthetic RuBisCO. Science 302 (2003) 286–290. [DOI] [PMID: 14551435]
[EC 3.1.3.87 created 2012]
 
 
EC 1.14.99.69     Relevance: 26.6%
Accepted name: tRNA 2-(methylsulfanyl)-N6-isopentenyladenosine37 hydroxylase
Reaction: 2-(methylsulfanyl)-N6-prenyladenosine37 in tRNA + reduced acceptor + O2 = N6-[(2E)-4-hydroxy-3-methylbut-2-en-1-yl]-2-(methylsulfanyl)adenosine37 in tRNA + acceptor + H2O
Glossary: 2-(methylsulfanyl)-N6-prenyladenosine = N6-(3-methylbut-2-en-1-yl)-2-(methylsulfanyl)adenosine
Other name(s): miaE (gene name); tRNA 2-methylthio-N6-isopentenyl adenosine(37) hydroxylase; tRNA 2-(methylsulfanyl)-N6-dimethylallyladenosine37 hydroxylase
Systematic name: tRNA 2-(methylsulfanyl)-N6-prenyladenosine37,donor:oxygen 4-oxidoreductase (trans-hydroxylating)
Comments: The enzyme, found only within a small subset of facultative anaerobic bacteria, belongs to the nonheme diiron family. The enzyme from Salmonella typhimurium was shown to catalyse a stereoselective (E)-hydroxylation at the terminal C4-position of the prenyl group.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Persson, B.C. and Bjork, G.R. Isolation of the gene (miaE) encoding the hydroxylase involved in the synthesis of 2-methylthio-cis-ribozeatin in tRNA of Salmonella typhimurium and characterization of mutants. J. Bacteriol. 175 (1993) 7776–7785. [DOI] [PMID: 8253666]
2.  Persson, B.C., Olafsson, O., Lundgren, H.K., Hederstedt, L. and Bjork, G.R. The ms2io6A37 modification of tRNA in Salmonella typhimurium regulates growth on citric acid cycle intermediates. J. Bacteriol. 180 (1998) 3144–3151. [DOI] [PMID: 9620964]
3.  Corder, A.L., Subedi, B.P., Zhang, S., Dark, A.M., Foss, F.W., Jr. and Pierce, B.S. Peroxide-shunt substrate-specificity for the Salmonella typhimurium O2-dependent tRNA modifying monooxygenase (MiaE). Biochemistry 52 (2013) 6182–6196. [DOI] [PMID: 23906247]
[EC 1.14.99.69 created 2020]
 
 
EC 4.1.2.62     Relevance: 26.4%
Accepted name: 5-deoxyribulose 1-phosphate aldolase
Reaction: (1) 5-deoxy-D-ribulose 1-phosphate = glycerone phosphate + acetaldehyde
(2) S-methyl-5-thio-D-ribulose 1-phosphate = glycerone phosphate + (2-methylsulfanyl)acetaldehyde
Other name(s): 5-(methylthio)ribulose-1-phosphate aldolase; ald2 (gene name)
Systematic name: 5-deoxy-D-ribulose 1-phosphate acetaldehyde-lyase (glycerone-phosphate-forming)
Comments: The enzyme, originally characterized from the bacterium Rhodospirillum rubrum, is involved in degradation pathways for 5′-deoxyadenosine and S-methyl-5′-thioadenosine, which are formed from S-adenosyl-L-methionine (SAM, AdoMet) by radical SAM enzymes and other types of SAM-dependent enzymes, respectively. The enzyme requires a divalent metal cation, with Co2+ producing the highest activity.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  North, J.A., Miller, A.R., Wildenthal, J.A., Young, S.J. and Tabita, F.R. Microbial pathway for anaerobic 5′-methylthioadenosine metabolism coupled to ethylene formation. Proc. Natl. Acad. Sci. USA 114 (2017) E10455–E10464. [PMID: 29133429]
2.  North, J.A., Wildenthal, J.A., Erb, T.J., Evans, B.S., Byerly, K.M., Gerlt, J.A. and Tabita, F.R. A bifunctional salvage pathway for two distinct S-adenosylmethionine by-products that is widespread in bacteria, including pathogenic Escherichia coli. Mol. Microbiol. (2020) . [PMID: 31950558]
[EC 4.1.2.62 created 2020]
 
 
EC 1.3.1.108     Relevance: 26.3%
Accepted name: caffeoyl-CoA reductase
Reaction: 3-(3,4-dihydroxyphenyl)propanoyl-CoA + 2 NAD+ + 2 reduced ferredoxin [iron-sulfur] cluster = (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl-CoA + 2 NADH + 2 oxidized ferredoxin [iron-sulfur] cluster
Glossary: (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl-CoA = (2E)-3-(3,4-dihydroxyphenyl)acryloyl-CoA = trans-caffeoyl-CoA
3-(3,4-dihydroxyphenyl)propanoyl-CoA = hydrocaffeoyl-CoA
Other name(s): electron-bifurcating caffeoyl-CoA reductase; caffeoyl-CoA reductase-Etf complex; hydrocaffeoyl-CoA:NAD+,ferredoxin oxidoreductase
Systematic name: 3-(3,4-dihydroxyphenyl)propanoyl-CoA:NAD+,ferredoxin oxidoreductase
Comments: The enzyme, characterized from the bacterium Acetobacterium woodii, contains two [4Fe-4S] clusters and FAD. The enzyme couples the endergonic ferredoxin reduction with NADH as reductant to the exergonic reduction of caffeoyl-CoA with the same reductant. It uses the mechanism of electron bifurcation to overcome the steep energy barrier in ferredoxin reduction. It also reduces 4-coumaroyl-CoA and feruloyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Bertsch, J., Parthasarathy, A., Buckel, W. and Muller, V. An electron-bifurcating caffeyl-CoA reductase. J. Biol. Chem. 288 (2013) 11304–11311. [DOI] [PMID: 23479729]
[EC 1.3.1.108 created 2015]
 
 
EC 2.3.3.17     Relevance: 25.3%
Accepted name: methylthioalkylmalate synthase
Reaction: an ω-(methylsulfanyl)-2-oxoalkanoate + acetyl-CoA + H2O = a 2-[ω-(methylsulfanyl)alkyl]malate + CoA
For diagram of L-Homomethionine biosynthesis, click here
Other name(s): MAM1 (gene name); MAM3 (gene name); acetyl-CoA:ω-(methylthio)-2-oxoalkanoate C-acetyltransferase
Systematic name: acetyl-CoA:ω-(methylsulfanyl)-2-oxoalkanoate C-acetyltransferase
Comments: The enzyme, characterized from the plant Arabidopsis thaliana, is involved in the L-methionine side-chain elongation pathway, forming substrates for the biosynthesis of aliphatic glucosinolates. Two forms are known - MAM1 catalyses only only the first two rounds of methionine chain elongation, while MAM3 catalyses all six cycles, up to formation of L-hexahomomethionine.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Textor, S., Bartram, S., Kroymann, J., Falk, K.L., Hick, A., Pickett, J.A. and Gershenzon, J. Biosynthesis of methionine-derived glucosinolates in Arabidopsis thaliana: recombinant expression and characterization of methylthioalkylmalate synthase, the condensing enzyme of the chain-elongation cycle. Planta 218 (2004) 1026–1035. [DOI] [PMID: 14740211]
2.  Textor, S., de Kraker, J.W., Hause, B., Gershenzon, J. and Tokuhisa, J.G. MAM3 catalyzes the formation of all aliphatic glucosinolate chain lengths in Arabidopsis. Plant Physiol. 144 (2007) 60–71. [DOI] [PMID: 17369439]
[EC 2.3.3.17 created 2016]
 
 
EC 4.2.1.109     Relevance: 24.8%
Accepted name: methylthioribulose 1-phosphate dehydratase
Reaction: 5-(methylsulfanyl)-D-ribulose 1-phosphate = 5-(methylsulfanyl)-2,3-dioxopentyl phosphate + H2O
For diagram of methionine salvage, click here
Other name(s): 1-PMT-ribulose dehydratase; S-methyl-5-thio-D-ribulose-1-phosphate hydro-lyase; S-methyl-5-thio-D-ribulose-1-phosphate 4-hydro-lyase [5-(methylthio)-2,3-dioxopentyl-phosphate-forming]
Systematic name: 5-(methylsulfanyl)-D-ribulose-1-phosphate 4-hydro-lyase [5-(methylsulfanyl)-2,3-dioxopentyl-phosphate-forming]
Comments: This enzyme forms part of the methionine-salvage pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 1114239-22-3
References:
1.  Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5′-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598–9606. [PMID: 2838472]
2.  Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147–3153. [DOI] [PMID: 7852397]
[EC 4.2.1.109 created 2006]
 
 
EC 2.5.1.23     Relevance: 24.8%
Accepted name: sym-norspermidine synthase
Reaction: S-adenosyl 3-(methylsulfanyl)propylamine + propane-1,3-diamine = S-methyl-5′-thioadenosine + bis(3-aminopropyl)amine
Glossary: S-adenosyl 3-(methylsulfanyl)propylamine = (3-aminopropyl){[(2S,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl}methylsulfonium
Other name(s): S-adenosylmethioninamine:propane-1,3-diamine 3-aminopropyltransferase; S-adenosyl 3-(methylthio)propylamine:propane-1,3-diamine 3-aminopropyltransferase
Systematic name: S-adenosyl 3-(methylsulfanyl)propylamine:propane-1,3-diamine 3-aminopropyltransferase
Comments: The enzyme has been originally characterized from the protist Euglena gracilis [1,2]. The enzyme from the archaeon Sulfolobus solfataricus can transfer the propylamine moiety from S-adenosyl 3-(methylsulfanyl)propylamine to putrescine, sym-norspermidine and spermidine with lower efficiency [3]. cf. EC 2.5.1.16 (spermidine synthase) and EC 2.5.1.22 (spermine synthase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Aleksijevic, A., Grove, J. and Schuber, F. Studies on polyamine biosynthesis in Euglena gracilis. Biochim. Biophys. Acta 565 (1979) 199–207. [DOI] [PMID: 116684]
2.  Villanueva, V.R., Adlakha, R.C. and Calbayrac, R. Biosynthesis of polyamines in Euglena gracilis. Phytochemistry 19 (1980) 787–790.
3.  Cacciapuoti, G., Porcelli, M., Carteni-Farina, M., Gambacorta, A. and Zappia, V. Purification and characterization of propylamine transferase from Sulfolobus solfataricus, an extreme thermophilic archaebacterium. Eur. J. Biochem. 161 (1986) 263–271. [DOI] [PMID: 3096734]
[EC 2.5.1.23 created 1983, modified 2013]
 
 
EC 2.5.1.22     Relevance: 24.2%
Accepted name: spermine synthase
Reaction: S-adenosyl 3-(methylsulfanyl)propylamine + spermidine = S-methyl-5′-thioadenosine + spermine
For diagram of spermine biosynthesis, click here
Glossary: spermidine = N-(3-aminopropyl)butane-1,4-diamine
spermine = N,N′-bis(3-aminopropyl)butane-1,4-diamine
S-adenosyl 3-(methylsulfanyl)propylamine = (3-aminopropyl){[(2S,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl}methylsulfonium
Other name(s): spermidine aminopropyltransferase; spermine synthetase; S-adenosylmethioninamine:spermidine 3-aminopropyltransferase; S-adenosyl 3-(methylthio)propylamine:spermidine 3-aminopropyltransferase
Systematic name: S-adenosyl 3-(methylsulfanyl)propylamine:spermidine 3-aminopropyltransferase
Comments: The enzyme from mammalia is highly specific for spermidine [2,3]. cf. EC 2.5.1.16 (spermidine synthase) and EC 2.5.1.23 (sym-norspermidine synthase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 74812-43-4
References:
1.  Hibasami, H., Borchardt, R.T., Chen, S.-Y., Coward, J.K. and Pegg, A.E. Studies of inhibition of rat spermidine synthase and spermine synthase. Biochem. J. 187 (1980) 419–428. [PMID: 7396856]
2.  Pajula, R.-L., Raina, A. and Eloranta, T. Polyamine synthesis in mammalian tissues. Isolation and characterization of spermine synthase from bovine brain. Eur. J. Biochem. 101 (1979) 619–626. [DOI] [PMID: 520313]
3.  Pegg, A.E., Shuttleworth, K. and Hibasami, H. Specificity of mammalian spermidine synthase and spermine synthase. Biochem. J. 197 (1981) 315–320. [PMID: 6798961]
[EC 2.5.1.22 created 1982, modified 2013]
 
 
EC 2.4.2.28     Relevance: 23.9%
Accepted name: S-methyl-5′-thioadenosine phosphorylase
Reaction: S-methyl-5′-thioadenosine + phosphate = adenine + S-methyl-5-thio-α-D-ribose 1-phosphate
For diagram of methionine salvage, click here
Other name(s): 5′-deoxy-5′-methylthioadenosine phosphorylase; MTA phosphorylase; MeSAdo phosphorylase; MeSAdo/Ado phosphorylase; methylthioadenosine phosphorylase; methylthioadenosine nucleoside phosphorylase; 5′-methylthioadenosine:phosphate methylthio-D-ribosyl-transferase; S-methyl-5-thioadenosine phosphorylase; S-methyl-5-thioadenosine:phosphate S-methyl-5-thio-α-D-ribosyl-transferase
Systematic name: S-methyl-5′-thioadenosine:phosphate S-methyl-5-thio-α-D-ribosyl-transferase
Comments: Also acts on 5′-deoxyadenosine and other analogues having 5′-deoxy groups.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 61970-06-7
References:
1.  Carteni-Farina, M., Oliva, A., Romeo, G., Napolitano, G., De Rosa, M., Gambacorta, A. and Zappia, V. 5′-Methylthioadenosine phosphorylase from Caldariella acidophila. Purification and properties. Eur. J. Biochem. 101 (1979) 317–324. [DOI] [PMID: 118001]
2.  Garbers, D.L. Demonstration of 5′-methylthioadenosine phosphorylase activity in various rat tissues. Some properties of the enzyme from rat lung. Biochim. Biophys. Acta 523 (1978) 82–93. [DOI] [PMID: 415762]
3.  Pegg, A.E. and Williams-Ashman, H.G. Phosphate-stimulated breakdown of 5′-methylthioadenosine by rat ventral prostate. Biochem. J. 115 (1969) 241–247. [PMID: 5378381]
[EC 2.4.2.28 created 1983]
 
 
EC 1.13.11.53     Relevance: 23.3%
Accepted name: acireductone dioxygenase (Ni2+-requiring)
Reaction: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + O2 = 3-(methylsulfanyl)propanoate + formate + CO
For diagram of methionine salvage, click here and for diagram of reaction, click here
Glossary: acireductone = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one
Other name(s): ARD; 2-hydroxy-3-keto-5-thiomethylpent-1-ene dioxygenase (ambiguous); acireductone dioxygenase (ambiguous); E-2; 1,2-dihydroxy-5-(methylthio)pent-1-en-3-one:oxygen oxidoreductase (formate- and CO-forming)
Systematic name: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one:oxygen oxidoreductase (formate- and CO-forming)
Comments: Requires Ni2+. If iron(II) is bound instead of Ni2+, the reaction catalysed by EC 1.13.11.54, acireductone dioxygenase [iron(II)-requiring], occurs instead [1]. The enzyme from the bacterium Klebsiella oxytoca (formerly Klebsiella pneumoniae) ATCC strain 8724 is involved in the methionine salvage pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Wray, J.W. and Abeles, R.H. A bacterial enzyme that catalyzes formation of carbon monoxide. J. Biol. Chem. 268 (1993) 21466–21469. [PMID: 8407993]
2.  Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147–3153. [DOI] [PMID: 7852397]
3.  Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5′-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598–9606. [PMID: 2838472]
4.  Dai, Y., Wensink, P.C. and Abeles, R.H. One protein, two enzymes. J. Biol. Chem. 274 (1999) 1193–1195. [DOI] [PMID: 9880484]
5.  Mo, H., Dai, Y., Pochapsky, S.S. and Pochapsky, T.C. 1H, 13C and 15N NMR assignments for a carbon monoxide generating metalloenzyme from Klebsiella pneumoniae. J. Biomol. NMR 14 (1999) 287–288. [PMID: 10481280]
6.  Dai, Y., Pochapsky, T.C. and Abeles, R.H. Mechanistic studies of two dioxygenases in the methionine salvage pathway of Klebsiella pneumoniae. Biochemistry 40 (2001) 6379–6387. [DOI] [PMID: 11371200]
7.  Al-Mjeni, F., Ju, T., Pochapsky, T.C. and Maroney, M.J. XAS investigation of the structure and function of Ni in acireductone dioxygenase. Biochemistry 41 (2002) 6761–6769. [DOI] [PMID: 12022880]
8.  Pochapsky, T.C., Pochapsky, S.S., Ju, T., Mo, H., Al-Mjeni, F. and Maroney, M.J. Modeling and experiment yields the structure of acireductone dioxygenase from Klebsiella pneumoniae. Nat. Struct. Biol. 9 (2002) 966–972. [DOI] [PMID: 12402029]
[EC 1.13.11.53 created 2006]
 
 
EC 5.3.1.23     Relevance: 23.2%
Accepted name: S-methyl-5-thioribose-1-phosphate isomerase
Reaction: S-methyl-5-thio-α-D-ribose 1-phosphate = S-methyl-5-thio-D-ribulose 1-phosphate
For diagram of the methionine-salvage pathway, click here
Other name(s): methylthioribose 1-phosphate isomerase; 1-PMTR isomerase; 5-methylthio-5-deoxy-D-ribose-1-phosphate ketol-isomerase; S-methyl-5-thio-5-deoxy-D-ribose-1-phosphate ketol-isomerase; S-methyl-5-thio-5-deoxy-D-ribose-1-phosphate aldose-ketose-isomerase; 1-phospho-5′-S-methylthioribose isomerase; S-methyl-5-thio-D-ribose-1-phosphate aldose-ketose-isomerase
Systematic name: S-methyl-5-thio-α-D-ribose-1-phosphate aldose-ketose-isomerase
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 91608-95-6
References:
1.  Ghoda, L.Y., Savarese, T.M., Dexter, D.L., Parks, R.E., Jr., Trackman, P.C. and Abeles, R.H. Characterization of a defect in the pathway for converting 5′-deoxy-5′-methylthioadenosine to methionine in a subline of a cultured heterogeneous human colon carcinoma. J. Biol. Chem. 259 (1984) 6715–6719. [PMID: 6725268]
2.  Trackman, P.C. and Abeles, R.H. Methionine synthesis from 5′-S-methylthioadenosine. Resolution of enzyme activities and identification of 1-phospho-5-S-methylthioribulose. J. Biol. Chem. 258 (1983) 6717–6720. [PMID: 6853500]
3.  Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5′-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598–9606. [PMID: 2838472]
[EC 5.3.1.23 created 1989]
 
 
EC 1.13.11.54     Relevance: 23%
Accepted name: acireductone dioxygenase [iron(II)-requiring]
Reaction: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + O2 = 4-(methylsulfanyl)-2-oxobutanoate + formate
For diagram of methionine salvage, click here and for diagram of reaction, click here
Glossary: acireductone = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one
Other name(s): ARD′; 2-hydroxy-3-keto-5-thiomethylpent-1-ene dioxygenase (ambiguous); acireductone dioxygenase (ambiguous); E-2′; E-3 dioxygenase; 1,2-dihydroxy-5-(methylthio)pent-1-en-3-one:oxygen oxidoreductase (formate-forming)
Systematic name: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one:oxygen oxidoreductase (formate-forming)
Comments: Requires iron(II). If Ni2+ is bound instead of iron(II), the reaction catalysed by EC 1.13.11.53, acireductone dioxygenase (Ni2+-requiring), occurs instead. The enzyme from the bacterium Klebsiella oxytoca (formerly Klebsiella pneumoniae) ATCC strain 8724 is involved in the methionine salvage pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Wray, J.W. and Abeles, R.H. A bacterial enzyme that catalyzes formation of carbon monoxide. J. Biol. Chem. 268 (1993) 21466–21469. [PMID: 8407993]
2.  Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147–3153. [DOI] [PMID: 7852397]
3.  Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5′-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598–9606. [PMID: 2838472]
4.  Dai, Y., Wensink, P.C. and Abeles, R.H. One protein, two enzymes. J. Biol. Chem. 274 (1999) 1193–1195. [DOI] [PMID: 9880484]
5.  Mo, H., Dai, Y., Pochapsky, S.S. and Pochapsky, T.C. 1H, 13C and 15N NMR assignments for a carbon monoxide generating metalloenzyme from Klebsiella pneumoniae. J. Biomol. NMR 14 (1999) 287–288. [PMID: 10481280]
6.  Dai, Y., Pochapsky, T.C. and Abeles, R.H. Mechanistic studies of two dioxygenases in the methionine salvage pathway of Klebsiella pneumoniae. Biochemistry 40 (2001) 6379–6387. [DOI] [PMID: 11371200]
7.  Al-Mjeni, F., Ju, T., Pochapsky, T.C. and Maroney, M.J. XAS investigation of the structure and function of Ni in acireductone dioxygenase. Biochemistry 41 (2002) 6761–6769. [DOI] [PMID: 12022880]
8.  Pochapsky, T.C., Pochapsky, S.S., Ju, T., Mo, H., Al-Mjeni, F. and Maroney, M.J. Modeling and experiment yields the structure of acireductone dioxygenase from Klebsiella pneumoniae. Nat. Struct. Biol. 9 (2002) 966–972. [DOI] [PMID: 12402029]
[EC 1.13.11.54 created 2006]
 
 
EC 2.5.1.104     Relevance: 22.5%
Accepted name: N1-aminopropylagmatine synthase
Reaction: S-adenosyl 3-(methylsulfanyl)propylamine + agmatine = S-methyl-5′-thioadenosine + N1-(3-aminopropyl)agmatine
For diagram of spermidine biosynthesis, click here
Glossary: S-adenosyl 3-(methylsulfanyl)propylamine = (3-aminopropyl){[(2S,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl}methylsulfonium
Other name(s): agmatine/cadaverine aminopropyl transferase; ACAPT; PF0127 (gene name); triamine/agmatine aminopropyltransferase; SpeE (ambiguous); agmatine aminopropyltransferase; S-adenosyl 3-(methylthio)propylamine:agmatine 3-aminopropyltransferase
Systematic name: S-adenosyl 3-(methylsulfanyl)propylamine:agmatine 3-aminopropyltransferase
Comments: The enzyme is involved in the biosynthesis of spermidine from agmatine in some archaea and bacteria. The enzyme from the Gram-negative bacterium Thermus thermophilus accepts agmatine, spermidine and norspermidine with similar catalytic efficiency. The enzymes from the archaea Pyrococcus furiosus and Thermococcus kodakarensis prefer agmatine, but can utilize cadaverine, putrescine and propane-1,3-diamine with much lower catalytic efficiency. cf. EC 2.5.1.16, spermidine synthase, and EC 2.5.1.23, sym-norspermidine synthase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Ohnuma, M., Terui, Y., Tamakoshi, M., Mitome, H., Niitsu, M., Samejima, K., Kawashima, E. and Oshima, T. N1-aminopropylagmatine, a new polyamine produced as a key intermediate in polyamine biosynthesis of an extreme thermophile, Thermus thermophilus. J. Biol. Chem. 280 (2005) 30073–30082. [DOI] [PMID: 15983049]
2.  Cacciapuoti, G., Porcelli, M., Moretti, M.A., Sorrentino, F., Concilio, L., Zappia, V., Liu, Z.J., Tempel, W., Schubot, F., Rose, J.P., Wang, B.C., Brereton, P.S., Jenney, F.E. and Adams, M.W. The first agmatine/cadaverine aminopropyl transferase: biochemical and structural characterization of an enzyme involved in polyamine biosynthesis in the hyperthermophilic archaeon Pyrococcus furiosus. J. Bacteriol. 189 (2007) 6057–6067. [DOI] [PMID: 17545282]
3.  Morimoto, N., Fukuda, W., Nakajima, N., Masuda, T., Terui, Y., Kanai, T., Oshima, T., Imanaka, T. and Fujiwara, S. Dual biosynthesis pathway for longer-chain polyamines in the hyperthermophilic archaeon Thermococcus kodakarensis. J. Bacteriol. 192 (2010) 4991–5001. [DOI] [PMID: 20675472]
4.  Ohnuma, M., Ganbe, T., Terui, Y., Niitsu, M., Sato, T., Tanaka, N., Tamakoshi, M., Samejima, K., Kumasaka, T. and Oshima, T. Crystal structures and enzymatic properties of a triamine/agmatine aminopropyltransferase from Thermus thermophilus. J. Mol. Biol. 408 (2011) 971–986. [DOI] [PMID: 21458463]
[EC 2.5.1.104 created 2013]
 
 
EC 2.5.1.16     Relevance: 22.4%
Accepted name: spermidine synthase
Reaction: S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5′-thioadenosine + spermidine
For diagram of spermine biosynthesis, click here
Glossary: spermidine = N-(3-aminopropyl)butane-1,4-diamine
spermine = N,N′-bis(3-aminopropyl)butane-1,4-diamine
putrescine = butane-1,4-diamine
S-adenosyl 3-(methylsulfanyl)propylamine = (3-aminopropyl){[(2S,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl}methylsulfonium
Other name(s): aminopropyltransferase; putrescine aminopropyltransferase; spermidine synthetase; SpeE (ambiguous); S-adenosylmethioninamine:putrescine 3-aminopropyltransferase; S-adenosyl 3-(methylthio)propylamine:putrescine 3-aminopropyltransferase
Systematic name: S-adenosyl 3-(methylsulfanyl)propylamine:putrescine 3-aminopropyltransferase
Comments: The enzymes from the plant Glycine max and from mammalia are highly specific for putrescine as the amine acceptor [2,7]. The enzymes from the bacteria Escherichia coli and Thermotoga maritima prefer putrescine but are more tolerant towards other amine acceptors, such as spermidine and cadaverine [5,6]. cf. EC 2.5.1.22 (spermine synthase) and EC 2.5.1.23 (sym-norspermidine synthase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37277-82-0
References:
1.  Hannonen, P., Janne, J. and Raina, A. Partial purification and characterization of spermine synthase from rat brain. Biochim. Biophys. Acta 289 (1972) 225–231. [DOI] [PMID: 4564056]
2.  Pegg, A.E., Shuttleworth, K. and Hibasami, H. Specificity of mammalian spermidine synthase and spermine synthase. Biochem. J. 197 (1981) 315–320. [PMID: 6798961]
3.  Tabor, C.W. Propylamine transferase (spermidine synthesis). Methods Enzymol. 5 (1962) 761–765.
4.  Tabor, H. and Tabor, C.W. Biosynthesis and metabolism of 1,4-diaminobutane, spermidine, spermine, and related amines. Adv. Enzymol. Relat. Areas Mol. Biol. 36 (1972) 203–268. [PMID: 4628436]
5.  Bowman, W.H., Tabor, C.W. and Tabor, H. Spermidine biosynthesis. Purification and properties of propylamine transferase from Escherichia coli. J. Biol. Chem. 248 (1973) 2480–2486. [PMID: 4572733]
6.  Korolev, S., Ikeguchi, Y., Skarina, T., Beasley, S., Arrowsmith, C., Edwards, A., Joachimiak, A., Pegg, A.E. and Savchenko, A. The crystal structure of spermidine synthase with a multisubstrate adduct inhibitor. Nat. Struct. Biol. 9 (2002) 27–31. [DOI] [PMID: 11731804]
7.  Yoon, S.O., Lee, Y.S., Lee, S.H. and Cho, Y.D. Polyamine synthesis in plants: isolation and characterization of spermidine synthase from soybean (Glycine max) axes. Biochim. Biophys. Acta 1475 (2000) 17–26. [DOI] [PMID: 10806333]
[EC 2.5.1.16 created 1972, modified 1982, modified 2013]
 
 
EC 3.1.3.77     Relevance: 21.8%
Accepted name: acireductone synthase
Reaction: 5-(methylsulfanyl)-2,3-dioxopentyl phosphate + H2O = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + phosphate (overall reaction)
(1a) 5-(methylsulfanyl)-2,3-dioxopentyl phosphate = 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate (probably spontaneous)
(1b) 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate + H2O = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + phosphate
For diagram of methionine salvage, click here
Glossary: acireductone = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one
Other name(s): E1; E-1 enolase-phosphatase; 5-(methylthio)-2,3-dioxopentyl-phosphate phosphohydrolase (isomerizing)
Systematic name: 5-(methylsulfanyl)-2,3-dioxopentyl-phosphate phosphohydrolase (isomerizing)
Comments: This bifunctional enzyme first enolizes the substrate to form the intermediate 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate, which is then dephosphorylated to form the acireductone 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one [2]. The acireductone represents a branch point in the methione-salvage pathway as it is used in the formation of formate, CO and 3-(methylsulfanyl)propanoate by EC 1.13.11.53 [acireductone dioxygenase (Ni2+-requiring)] and of formate and 4-(methylsulfanyl)-2-oxobutanoate either by a spontaneous reaction under aerobic conditions or by EC 1.13.11.54 {acireductone dioxygenase [iron(II)-requiring]} [1,2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Myers, R.W., Wray, J.W., Fish, S. and Abeles, R.H. Purification and characterization of an enzyme involved in oxidative carbon-carbon bond cleavage reactions in the methionine salvage pathway of Klebsiella pneumoniae. J. Biol. Chem. 268 (1993) 24785–24791. [PMID: 8227039]
2.  Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147–3153. [DOI] [PMID: 7852397]
3.  Wang, H., Pang, H., Bartlam, M. and Rao, Z. Crystal structure of human E1 enzyme and its complex with a substrate analog reveals the mechanism of its phosphatase/enolase activity. J. Mol. Biol. 348 (2005) 917–926. [DOI] [PMID: 15843022]
[EC 3.1.3.77 created 2006]
 
 
EC 2.8.4.5     Relevance: 19.7%
Accepted name: tRNA (N6-L-threonylcarbamoyladenosine37-C2)-methylthiotransferase
Reaction: N6-L-threonylcarbamoyladenine37 in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine + reduced electron acceptor = 2-(methylsulfanyl)-N6-L-threonylcarbamoyladenine37 in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5′-deoxyadenosine + electron acceptor (overall reaction)
(1a) N6-L-threonylcarbamoyladenine37 in tRNA + sulfur-(sulfur carrier) + S-adenosyl-L-methionine + reduced electron acceptor = 2-sulfanyl-N6-L-threonylcarbamoyladenine37 in tRNA + (sulfur carrier) + L-methionine + 5′-deoxyadenosine + electron acceptor
(1b) S-adenosyl-L-methionine + 2-sulfanyl-N6-L-threonylcarbamoyladenine37 in tRNA = S-adenosyl-L-homocysteine + 2-(methylsulfanyl)-N6-L-threonylcarbamoyladenine37 in tRNA
For diagram of N6-L-Threonylcarbamoyladenosine37 modified tRNA biosynthesis, click here
Glossary: N6-L-threonylcarbamoyladenine37 = t6A37
2-sulfanyl-N6-L-threonylcarbamoyladenine37 = ms2t6A37
Other name(s): MtaB; methylthio-threonylcarbamoyl-adenosine transferase B; CDKAL1 (gene name); tRNA (N6-L-threonylcarbamoyladenosine37):sulfur-(sulfur carrier),S-adenosyl-L-methionine C2-methylthiotransferase
Systematic name: tRNA (N6-L-threonylcarbamoyladenosine37):sulfur-(sulfur carrier),S-adenosyl-L-methionine C2-(methylsulfanyl)transferase
Comments: The enzyme, which is a member of the S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes superfamily, binds two [4Fe-4S] clusters as well as the transferred sulfur. The sulfur donor is believed to be one of the [4Fe-4S] clusters, which is sacrificed in the process, so that in vitro the reaction is a single turnover. The identity of the electron donor is not known.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Arragain, S., Handelman, S.K., Forouhar, F., Wei, F.Y., Tomizawa, K., Hunt, J.F., Douki, T., Fontecave, M., Mulliez, E. and Atta, M. Identification of eukaryotic and prokaryotic methylthiotransferase for biosynthesis of 2-methylthio-N6-threonylcarbamoyladenosine in tRNA. J. Biol. Chem. 285 (2010) 28425–28433. [DOI] [PMID: 20584901]
[EC 2.8.4.5 created 2014, modified 2015]
 
 


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