The Enzyme Database

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EC 1.1.1.202     
Accepted name: 1,3-propanediol dehydrogenase
Reaction: propane-1,3-diol + NAD+ = 3-hydroxypropanal + NADH + H+
Other name(s): 3-hydroxypropionaldehyde reductase; 1,3-PD:NAD+ oxidoreductase; 1,3-propanediol:NAD+ oxidoreductase; 1,3-propanediol dehydrogenase
Systematic name: propane-1,3-diol:NAD+ 1-oxidoreductase
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 81611-70-3
References:
1.  Abeles, R.H., Brownstein, A.M. and Randles, C.H. α-Hydroxypropionaldehyde, an intermediate in the formation of 1,3-propanediol by Aerobacter melanogaster. Biochim. Biophys. Acta 41 (1960) 530. [DOI] [PMID: 13791444]
2.  Forage, R.G. and Foster, M.A. Glycerol fermentation in Klebsiella pneumoniae: functions of the coenzyme B12-dependent glycerol and diol dehydratases. J. Bacteriol. 149 (1982) 413–419. [PMID: 7035429]
[EC 1.1.1.202 created 1984]
 
 
EC 1.1.1.337     
Accepted name: L-2-hydroxycarboxylate dehydrogenase (NAD+)
Reaction: a (2S)-2-hydroxycarboxylate + NAD+ = a 2-oxocarboxylate + NADH + H+
Other name(s): (R)-sulfolactate:NAD+ oxidoreductase; L-sulfolactate dehydrogenase; (R)-sulfolactate dehydrogenase; L-2-hydroxyacid dehydrogenase (NAD+); ComC
Systematic name: (2S)-2-hydroxycarboxylate:NAD+ oxidoreductase
Comments: The enzyme from the archaeon Methanocaldococcus jannaschii acts on multiple (S)-2-hydroxycarboxylates including (2R)-3-sulfolactate, (S)-malate, (S)-lactate, and (S)-2-hydroxyglutarate [3]. Note that (2R)-3-sulfolactate has the same stereo configuration as (2S)-2-hydroxycarboxylates.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 81210-65-3
References:
1.  Graupner, M., Xu, H. and White, R.H. Identification of an archaeal 2-hydroxy acid dehydrogenase catalyzing reactions involved in coenzyme biosynthesis in methanoarchaea. J. Bacteriol. 182 (2000) 3688–3692. [DOI] [PMID: 10850983]
2.  Graupner, M. and White, R.H. The first examples of (S)-2-hydroxyacid dehydrogenases catalyzing the transfer of the pro-4S hydrogen of NADH are found in the archaea. Biochim. Biophys. Acta 1548 (2001) 169–173. [DOI] [PMID: 11451450]
3.  Graham, D.E. and White, R.H. Elucidation of methanogenic coenzyme biosyntheses: from spectroscopy to genomics. Nat. Prod. Rep. 19 (2002) 133–147. [PMID: 12013276]
4.  Rein, U., Gueta, R., Denger, K., Ruff, J., Hollemeyer, K. and Cook, A.M. Dissimilation of cysteate via 3-sulfolactate sulfo-lyase and a sulfate exporter in Paracoccus pantotrophus NKNCYSA. Microbiology 151 (2005) 737–747. [DOI] [PMID: 15758220]
[EC 1.1.1.337 created 2012]
 
 
EC 1.1.1.375     
Accepted name: L-2-hydroxycarboxylate dehydrogenase [NAD(P)+]
Reaction: a (2S)-2-hydroxycarboxylate + NAD(P)+ = a 2-oxocarboxylate + NAD(P)H + H+
Other name(s): MdhII; lactate/malate dehydrogenase
Systematic name: (2S)-2-hydroxycarboxylate:NAD(P)+ oxidoreductase
Comments: The enzyme from the archaeon Methanocaldococcus jannaschii catalyses the reversible oxidation of (2R)-3-sulfolactate and (S)-malate to 3-sulfopyruvate and oxaloacetate, respectively (note that (2R)-3-sulfolactate has the same stereochemical configuration as (2S)-2-hydroxycarboxylates) [1]. The enzyme can use both NADH and NADPH, although activity is higher with NADPH [1-3]. The oxidation of (2R)-3-sulfolactate was observed only in the presence of NADP+ [1]. The same organism also possesses an NAD+-specific enzyme with similar activity, cf. EC 1.1.1.337, L-2-hydroxycarboxylate dehydrogenase (NAD+).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Graupner, M., Xu, H. and White, R.H. Identification of an archaeal 2-hydroxy acid dehydrogenase catalyzing reactions involved in coenzyme biosynthesis in methanoarchaea. J. Bacteriol. 182 (2000) 3688–3692. [DOI] [PMID: 10850983]
2.  Lee, B.I., Chang, C., Cho, S.J., Eom, S.H., Kim, K.K., Yu, Y.G. and Suh, S.W. Crystal structure of the MJ0490 gene product of the hyperthermophilic archaebacterium Methanococcus jannaschii, a novel member of the lactate/malate family of dehydrogenases. J. Mol. Biol. 307 (2001) 1351–1362. [DOI] [PMID: 11292347]
3.  Madern, D. The putative L-lactate dehydrogenase from Methanococcus jannaschii is an NADPH-dependent L-malate dehydrogenase. Mol. Microbiol. 37 (2000) 1515–1520. [DOI] [PMID: 10998181]
[EC 1.1.1.375 created 2014]
 
 
EC 1.1.98.5     
Accepted name: secondary-alcohol dehydrogenase (coenzyme-F420)
Reaction: R-CHOH-R′ + oxidized coenzyme F420 = R-CO-R′ + reduced coenzyme F420
Glossary: oxidized coenzyme F420 = N-(N-{O-[5-(8-hydroxy-2,4-dioxo-2,3,4,10-tetrahydropyrimido[4,5-b]quinolin-10-yl)-5-deoxy-L-ribityl-1-phospho]-(S)-lactyl}-γ-L-glutamyl)-L-glutamate
Other name(s): F420-dependent alcohol dehydrogenase; secondary alcohol:F420 oxidoreductase; F420-dependent secondary alcohol dehydrogenase
Systematic name: secondary-alcohol:coenzyme F420 oxidoreductase
Comments: The enzyme isolated from the methanogenic archaea Methanogenium liminatans catalyses the reversible oxidation of various secondary and cyclic alcohols to the corresponding ketones.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Bleicher, K. and Winter, J. Purification and properties of F420- and NADP+-dependent alcohol dehydrogenases of Methanogenium liminatans and Methanobacterium palustre, specific for secondary alcohols. Eur. J. Biochem. 200 (1991) 43–51. [DOI] [PMID: 1879431]
2.  Aufhammer, S.W., Warkentin, E., Berk, H., Shima, S., Thauer, R.K. and Ermler, U. Coenzyme binding in F420-dependent secondary alcohol dehydrogenase, a member of the bacterial luciferase family. Structure 12 (2004) 361–370. [DOI] [PMID: 15016352]
[EC 1.1.98.5 created 2013]
 
 
EC 1.2.1.72     
Accepted name: erythrose-4-phosphate dehydrogenase
Reaction: D-erythrose 4-phosphate + NAD+ + H2O = 4-phosphoerythronate + NADH + 2 H+
For diagram of pyridoxal biosynthesis, click here
Other name(s): erythrose 4-phosphate dehydrogenase; E4PDH; GapB; Epd dehydrogenase; E4P dehydrogenase
Systematic name: D-erythrose 4-phosphate:NAD+ oxidoreductase
Comments: This enzyme was originally thought to be a glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), but this has since been disproved, as glyceraldehyde 3-phosphate is not a substrate [1,2]. Forms part of the pyridoxal-5′-phosphate coenzyme biosynthesis pathway in Escherichia coli, along with EC 1.1.1.290 (4-phosphoerythronate dehydrogenase), EC 2.6.1.52 (phosphoserine transaminase), EC 1.1.1.262 (4-hydroxythreonine-4-phosphate dehydrogenase), EC 2.6.99.2 (pyridoxine 5′-phosphate synthase) and EC 1.4.3.5 (pyridoxamine-phosphate oxidase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 131554-04-6
References:
1.  Zhao, G., Pease, A.J., Bharani, N. and Winkler, M.E. Biochemical characterization of gapB-encoded erythrose 4-phosphate dehydrogenase of Escherichia coli K-12 and its possible role in pyridoxal 5′-phosphate biosynthesis. J. Bacteriol. 177 (1995) 2804–2812. [DOI] [PMID: 7751290]
2.  Boschi-Muller, S., Azza, S., Pollastro, D., Corbier, C. and Branlant, G. Comparative enzymatic properties of GapB-encoded erythrose-4-phosphate dehydrogenase of Escherichia coli and phosphorylating glyceraldehyde-3-phosphate dehydrogenase. J. Biol. Chem. 272 (1997) 15106–15112. [DOI] [PMID: 9182530]
3.  Yang, Y., Zhao, G., Man, T.K. and Winkler, M.E. Involvement of the gapA- and epd (gapB)-encoded dehydrogenases in pyridoxal 5′-phosphate coenzyme biosynthesis in Escherichia coli K-12. J. Bacteriol. 180 (1998) 4294–4299. [PMID: 9696782]
[EC 1.2.1.72 created 2006]
 
 
EC 1.3.4.1     
Accepted name: fumarate reductase (CoM/CoB)
Reaction: fumarate + CoM + CoB = succinate + CoM-S-S-CoB
Glossary: CoB = coenzyme B = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
CoM = coenzyme M = 2-mercaptoethanesulfonate
Other name(s): thiol:fumarate reductase; Tfr
Systematic name: fumarate CoM:CoB oxidoreductase (succinate-forming)
Comments: The enzyme, isolated from the archaeon Methanobacterium thermoautotrophicum, is very oxygen sensitive. It cannot use reduced flavins, reduced coenzyme F420, or NAD(P)H as an electron donor. Distinct from EC 1.3.1.6 [fumarate reductase (NADH)], EC 1.3.5.1 [succinate dehydrogenase (ubiquinone)], and EC 1.3.5.4 [fumarate reductase (quinol)].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Khandekar, S.S. and Eirich, L.D. Purification and characterization of an anabolic fumarate reductase from Methanobacterium thermoautotrophicum. Appl. Environ. Microbiol. 55 (1989) 856–861. [PMID: 2499256]
2.  Heim, S., Kunkel, A., Thauer, R.K. and Hedderich, R. Thiol:fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum. Identification of the catalytic sites for fumarate reduction and thiol oxidation. Eur. J. Biochem. 253 (1998) 292–299. [DOI] [PMID: 9578488]
[EC 1.3.4.1 created 2014 as EC 1.3.98.2, transferred 2014 to EC 1.3.4.1]
 
 
EC 1.4.3.16     
Accepted name: L-aspartate oxidase
Reaction: L-aspartate + O2 = iminosuccinate + H2O2
Other name(s): NadB; Laspo; AO
Systematic name: L-aspartate:oxygen oxidoreductase
Comments: A flavoprotein (FAD). L-Aspartate oxidase catalyses the first step in the de novo biosynthesis of NAD+ in some bacteria. O2 can be replaced by fumarate as electron acceptor, yielding succinate [5]. The ability of the enzyme to use both O2 and fumarate in cofactor reoxidation enables it to function under both aerobic and anaerobic conditions [5]. Iminosuccinate can either be hydrolysed to form oxaloacetate and NH3 or can be used by EC 2.5.1.72, quinolinate synthase, in the production of quinolinate. The enzyme is a member of the succinate dehydrogenase/fumarate-reductase family of enzymes [5].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 69106-47-4
References:
1.  Nasu, S., Wicks, F.D. and Gholson, R.K. L-Aspartate oxidase, a newly discovered enzyme of Escherichia coli, is the B protein of quinolinate synthetase. J. Biol. Chem. 257 (1982) 626–632. [PMID: 7033218]
2.  Mortarino, M., Negri, A., Tedeschi, G., Simonic, T., Duga, S., Gassen, H.G. and Ronchi, S. L-aspartate oxidase from Escherichia coli. I. Characterization of coenzyme binding and product inhibition. Eur. J. Biochem. 239 (1996) 418–426. [DOI] [PMID: 8706749]
3.  Tedeschi, G., Negri, A., Mortarino, M., Ceciliani, F., Simonic, T., Faotto, L. and Ronchi, S. L-Aspartate oxidase from Escherichia coli. II. Interaction with C4 dicarboxylic acids and identification of a novel L-aspartate: fumarate oxidoreductase activity. Eur. J. Biochem. 239 (1996) 427–433. [DOI] [PMID: 8706750]
4.  Mattevi, A., Tedeschi, G., Bacchella, L., Coda, A., Negri, A. and Ronchi, S. Structure of L-aspartate oxidase: implications for the succinate dehydrogenase/fumarate reductase oxidoreductase family. Structure 7 (1999) 745–756. [DOI] [PMID: 10425677]
5.  Bossi, R.T., Negri, A., Tedeschi, G. and Mattevi, A. Structure of FAD-bound L-aspartate oxidase: insight into substrate specificity and catalysis. Biochemistry 41 (2002) 3018–3024. [DOI] [PMID: 11863440]
6.  Katoh, A., Uenohara, K., Akita, M. and Hashimoto, T. Early steps in the biosynthesis of NAD in Arabidopsis start with aspartate and occur in the plastid. Plant Physiol. 141 (2006) 851–857. [DOI] [PMID: 16698895]
[EC 1.4.3.16 created 1984, modified 2008]
 
 
EC 1.8.7.3     
Accepted name: ferredoxin:CoB-CoM heterodisulfide reductase
Reaction: 2 oxidized ferredoxin [iron-sulfur] cluster + CoB + CoM = 2 reduced ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB + 2 H+
Glossary: CoB = coenzyme B = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
CoM = coenzyme M = 2-mercaptoethanesulfonate
CoM-S-S-CoB = CoB-CoM heterodisulfide = N-{7-[(2-sulfoethyl)dithio]heptanoyl}-O3-phospho-L-threonine
Other name(s): hdrABC (gene names); hdrA1B1C1 (gene names); hdrA2B2C2 (gene names)
Systematic name: CoB,CoM:ferredoxin oxidoreductase
Comments: HdrABC is an enzyme complex that is found in most methanogens and catalyses the reduction of the CoB-CoM heterodisulfide back to CoB and CoM. HdrA contains a FAD cofactor that acts as the entry point for electrons, which are transferred via HdrC to the HdrB catalytic subunit. One form of the enzyme from Methanosarcina acetivorans (HdrA2B2C2) can also catalyse EC 1.8.98.4, coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase. cf. EC 1.8.98.5, H2:CoB-CoM heterodisulfide,ferredoxin reductase, EC 1.8.98.6, formate:CoB-CoM heterodisulfide,ferredoxin reductase, and EC 1.8.98.1, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Buan, N.R. and Metcalf, W.W. Methanogenesis by Methanosarcina acetivorans involves two structurally and functionally distinct classes of heterodisulfide reductase. Mol. Microbiol. 75 (2010) 843–853. [DOI] [PMID: 19968794]
2.  Yan, Z., Wang, M. and Ferry, J.G. A ferredoxin- and F420H2-dependent, electron-bifurcating, heterodisulfide reductase with homologs in the domains Bacteria and Archaea. mBio 8 (2017) e02285-16. [DOI] [PMID: 28174314]
[EC 1.8.7.3 created 2017]
 
 
EC 1.8.98.1     
Accepted name: dihydromethanophenazine:CoB-CoM heterodisulfide reductase
Reaction: CoB + CoM + methanophenazine = CoM-S-S-CoB + dihydromethanophenazine
For diagram of methane biosynthesis, click here
Glossary: CoB = coenzyme B = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate
CoM = coenzyme M = 2-mercaptoethanesulfonate
methanophenazine = 2-{[(6E,10E,14E)-3,7,11,15,19-pentamethylicosa-6,10,14,18-tetraen-1-yl]oxy}phenazine
CoM-S-S-CoB = CoB-CoM heterodisulfide = N-{7-[(2-sulfoethyl)dithio]heptanoyl}-O3-phospho-L-threonine
Other name(s): hdrDE (gene names); CoB—CoM heterodisulfide reductase (ambiguous); heterodisulfide reductase (ambiguous); coenzyme B:coenzyme M:methanophenazine oxidoreductase
Systematic name: CoB:CoM:methanophenazine oxidoreductase
Comments: This enzyme, found in methanogenic archaea that belong to the Methanosarcinales order, regenerates CoM and CoB after the action of EC 2.8.4.1, coenzyme-B sulfoethylthiotransferase. It is a membrane-bound enzyme that contains (per heterodimeric unit) two distinct b-type hemes and two [4Fe-4S] clusters. cf. EC 1.8.7.3, ferredoxin:CoB-CoM heterodisulfide reductase, EC 1.8.98.5, H2:CoB-CoM heterodisulfide,ferredoxin reductase, EC 1.8.98.6, formate:CoB-CoM heterodisulfide,ferredoxin reductase and EC 1.8.98.4, coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Hedderich, R., Berkessel, A. and Thauer, R.K. Purification and properties of heterodisulfide reductase from Methanobacterium thermoautotrophicum (strain Marburg). Eur. J. Biochem. 193 (1990) 255–261. [DOI] [PMID: 2121478]
2.  Abken, H.J., Tietze, M., Brodersen, J., Bäumer, S., Beifuss, U. and Deppenmeier, U. Isolation and characterization of methanophenazine and function of phenazines in membrane-bound electron transport of Methanosarcina mazei gol. J. Bacteriol. 180 (1998) 2027–2032. [PMID: 9555882]
3.  Simianu, M., Murakami, E., Brewer, J.M. and Ragsdale, S.W. Purification and properties of the heme- and iron-sulfur-containing heterodisulfide reductase from Methanosarcina thermophila. Biochemistry 37 (1998) 10027–10039. [DOI] [PMID: 9665708]
4.  Murakami, E., Deppenmeier, U. and Ragsdale, S.W. Characterization of the intramolecular electron transfer pathway from 2-hydroxyphenazine to the heterodisulfide reductase from Methanosarcina thermophila. J. Biol. Chem. 276 (2001) 2432–2439. [DOI] [PMID: 11034998]
[EC 1.8.98.1 created 2003, modified 2017]
 
 
EC 1.8.98.4     
Accepted name: coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase
Reaction: 2 oxidized coenzyme F420 + 2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+ = 2 reduced coenzyme F420 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
Glossary: CoB = coenzyme B = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
CoM = coenzyme M = 2-mercaptoethanesulfonate
CoM-S-S-CoB = CoB-CoM heterodisulfide = N-{7-[(2-sulfoethyl)dithio]heptanoyl}-O3-phospho-L-threonine
Other name(s): hdrA2B2C2 (gene names)
Systematic name: CoB,CoM,ferredoxin:coenzyme F420 oxidoreductase
Comments: The enzyme, characterized from the archaeon Methanosarcina acetivorans, catalyses the reduction of CoB-CoM heterodisulfide back to CoB and CoM. The enzyme consists of three components, HdrA, HdrB and HdrC, all of which contain [4Fe-4S] clusters. Electrons enter at HdrA, which also contains FAD, and are transferred via HdrC to the catalytic component, HdrB. During methanogenesis from acetate the enzyme catalyses the activity of EC 1.8.7.3, ferredoxin:CoB-CoM heterodisulfide reductase. However, it can also use electron bifurcation to direct electron pairs from reduced coenzyme F420 towards the reduction of both ferredoxin and CoB-CoM heterodisulfide. This activity is proposed to take place during Fe(III)-dependent anaerobic methane oxidation. cf. EC 1.8.98.5, H2:CoB-CoM heterodisulfide,ferredoxin reductase, EC 1.8.98.6, formate:CoB-CoM heterodisulfide,ferredoxin reductase, and EC 1.8.98.1, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Yan, Z., Wang, M. and Ferry, J.G. A ferredoxin- and F420H2-dependent, electron-bifurcating, heterodisulfide reductase with homologs in the domains Bacteria and Archaea. mBio 8 (2017) e02285-16. [DOI] [PMID: 28174314]
[EC 1.8.98.4 created 2017]
 
 
EC 1.8.98.5     
Accepted name: H2:CoB-CoM heterodisulfide,ferredoxin reductase
Reaction: 2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+ = 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
Glossary: CoB = coenzyme B = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
CoM = coenzyme M = 2-mercaptoethanesulfonate
CoM-S-S-CoB = CoB-CoM heterodisulfide = N-{7-[(2-sulfoethyl)dithio]heptanoyl}-O3-phospho-L-threonine
Systematic name: CoB,CoM,ferredoxin:H2 oxidoreductase
Comments: This enzyme complex is found in H2-oxidizing CO2-reducing methanogenic archaea such as Methanothermobacter thermautotrophicus. It consists of a cytoplasmic complex of HdrABC reductase and MvhAGD hydrogenase. Electron pairs donated by the hydrogenase are transferred via its δ subunit to the HdrA subunit of the reductase, where they are bifurcated, reducing both ferredoxin and CoB-CoM heterodisulfide. The reductase can also form a similar complex with formate dehydrogenase, see EC 1.8.98.6, formate:CoB-CoM heterodisulfide,ferredoxin reductase. cf. EC 1.8.7.3, ferredoxin:CoB-CoM heterodisulfide reductase, EC 1.8.98.4, coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase, and EC 1.8.98.1, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Reeve, J.N., Beckler, G.S., Cram, D.S., Hamilton, P.T., Brown, J.W., Krzycki, J.A., Kolodziej, A.F., Alex, L., Orme-Johnson, W.H. and Walsh, C.T. A hydrogenase-linked gene in Methanobacterium thermoautotrophicum strain δ H encodes a polyferredoxin. Proc. Natl. Acad. Sci. USA 86 (1989) 3031–3035. [DOI] [PMID: 2654933]
2.  Hedderich, R., Koch, J., Linder, D. and Thauer, R.K. The heterodisulfide reductase from Methanobacterium thermoautotrophicum contains sequence motifs characteristic of pyridine-nucleotide-dependent thioredoxin reductases. Eur. J. Biochem. 225 (1994) 253–261. [DOI] [PMID: 7925445]
3.  Setzke, E., Hedderich, R., Heiden, S. and Thauer, R.K. H2: heterodisulfide oxidoreductase complex from Methanobacterium thermoautotrophicum. Composition and properties. Eur. J. Biochem. 220 (1994) 139–148. [DOI] [PMID: 8119281]
4.  Stojanowic, A., Mander, G.J., Duin, E.C. and Hedderich, R. Physiological role of the F420-non-reducing hydrogenase (Mvh) from Methanothermobacter marburgensis. Arch. Microbiol. 180 (2003) 194–203. [DOI] [PMID: 12856108]
5.  Kaster, A.K., Moll, J., Parey, K. and Thauer, R.K. Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea. Proc. Natl. Acad. Sci. USA 108 (2011) 2981–2986. [DOI] [PMID: 21262829]
6.  Costa, K.C., Lie, T.J., Xia, Q. and Leigh, J.A. VhuD facilitates electron flow from H2 or formate to heterodisulfide reductase in Methanococcus maripaludis. J. Bacteriol. 195 (2013) 5160–5165. [DOI] [PMID: 24039260]
[EC 1.8.98.5 created 2017]
 
 
EC 1.8.98.6     
Accepted name: formate:CoB-CoM heterodisulfide,ferredoxin reductase
Reaction: 2 CO2 + 2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+ = 2 formate + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
Glossary: coenzyme B = CoB = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
coenzyme M = CoM = 2-mercaptoethanesulfonate
CoM-S-S-CoB = CoB-CoM heterodisulfide = N-{7-[(2-sulfoethyl)dithio]heptanoyl}-O3-phospho-L-threonine
Systematic name: coenzyme B,coenzyme M,ferredoxin:formate oxidoreductase
Comments: The enzyme is found in formate-oxidizing CO2-reducing methanogenic archaea such as Methanococcus maripaludis. It consists of a cytoplasmic complex of HdrABC reductase and formate dehydrogenase. Electron pairs donated by formate dehydrogenase are transferred to the HdrA subunit of the reductase, where they are bifurcated, reducing both ferredoxin and CoB-CoM heterodisulfide. cf. EC 1.8.7.3, ferredoxin:CoB-CoM heterodisulfide reductase, EC 1.8.98.4, coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase, EC 1.8.98.5, H2:CoB-CoM heterodisulfide,ferredoxin reductase, and EC 1.8.98.1, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Costa, K.C., Wong, P.M., Wang, T., Lie, T.J., Dodsworth, J.A., Swanson, I., Burn, J.A., Hackett, M. and Leigh, J.A. Protein complexing in a methanogen suggests electron bifurcation and electron delivery from formate to heterodisulfide reductase. Proc. Natl. Acad. Sci. USA 107 (2010) 11050–11055. [DOI] [PMID: 20534465]
2.  Costa, K.C., Lie, T.J., Xia, Q. and Leigh, J.A. VhuD facilitates electron flow from H2 or formate to heterodisulfide reductase in Methanococcus maripaludis. J. Bacteriol. 195 (2013) 5160–5165. [DOI] [PMID: 24039260]
[EC 1.8.98.6 created 2017]
 
 
EC 1.14.13.83     
Accepted name: precorrin-3B synthase
Reaction: precorrin-3A + NADH + H+ + O2 = precorrin-3B + NAD+ + H2O
For diagram of corrin biosynthesis (part 3), click here and for mechanism of reaction, click here
Other name(s): precorrin-3X synthase; CobG
Systematic name: precorrin-3A,NADH:oxygen oxidoreductase (20-hydroxylating)
Comments: An iron-sulfur protein. An oxygen atom from dioxygen is incorporated into the macrocycle at C-20. In the aerobic cobalamin biosythesis pathway, four enzymes are involved in the conversion of precorrin-3A to precorrin-6A. The first of the four steps is carried out by EC 1.14.13.83, precorrin-3B synthase (CobG), yielding precorrin-3B as the product. This is followed by three methylation reactions, which introduce a methyl group at C-17 (CobJ; EC 2.1.1.131), C-11 (CobM; EC 2.1.1.133) and C-1 (CobF; EC 2.1.1.152) of the macrocycle, giving rise to precorrin-4, precorrin-5 and precorrin-6A, respectively.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 152787-63-8
References:
1.  Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430–7440. [DOI] [PMID: 8226690]
2.  Scott, A.I., Roessner, C.A., Stolowich, N.J., Spencer, J.B., Min, C. and Ozaki, S.I. Biosynthesis of vitamin B12. Discovery of the enzymes for oxidative ring contraction and insertion of the fourth methyl group. FEBS Lett. 331 (1993) 105–108. [DOI] [PMID: 8405386]
3.  Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390–412. [PMID: 12195810]
[EC 1.14.13.83 created 2004]
 
 
EC 1.17.4.2     
Accepted name: ribonucleoside-triphosphate reductase (thioredoxin)
Reaction: 2′-deoxyribonucleoside 5′-triphosphate + thioredoxin disulfide + H2O = ribonucleoside 5′-triphosphate + thioredoxin
Other name(s): ribonucleotide reductase (ambiguous); 2′-deoxyribonucleoside-triphosphate:oxidized-thioredoxin 2′-oxidoreductase
Systematic name: 2′-deoxyribonucleoside-5′-triphosphate:thioredoxin-disulfide 2′-oxidoreductase
Comments: The enzyme, characterized from the bacterium Lactobacillus leichmannii, is similar to class II ribonucleoside-diphosphate reductase (cf. EC 1.17.4.1). However, it is specific for the triphosphate versions of its substrates. The enzyme contains an adenosylcobalamin cofactor that is involved in generation of a transient thiyl (sulfanyl) radical on a cysteine residue. This radical attacks the substrate, forming a ribonucleotide 3′-radical, followed by water loss to form a ketyl (α-oxoalkyl) radical. The ketyl radical is reduced to 3′-keto-deoxynucleotide concomitant with formation of a disulfide anion radical between two cysteine residues. A proton-coupled electron-transfer from the disulfide radical to the substrate generates a 3′-deoxynucleotide radical, and the final product is formed when the hydrogen atom that was initially removed from the 3′-position of the nucleotide by the thiyl radical is returned to the same position. The disulfide bridge is reduced by the action of thioredoxin. cf. EC 1.1.98.6, ribonucleoside-triphosphate reductase (formate).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9068-66-0
References:
1.  Blakley, R.L. Cobamides and ribonucleotide reduction. I. Cobamide stimulation of ribonucleotide reduction in extracts of Lactobacillus leichmannii. J. Biol. Chem. 240 (1965) 2173–2180. [PMID: 14299643]
2.  Goulian, M. and Beck, W.S. Purification and properties of cobamide-dependent ribonucleotide reductase from Lactobacillus leichmannii. J. Biol. Chem. 241 (1966) 4233–4242. [PMID: 5924645]
3.  Stubbe, J., Ackles, D., Segal, R. and Blakley, R.L. On the mechanism of ribonucleoside triphosphate reductase from Lactobacillus leichmannii. Evidence for 3′ C--H bond cleavage. J. Biol. Chem. 256 (1981) 4843–4846. [PMID: 7014560]
4.  Ashley, G.W., Harris, G. and Stubbe, J. The mechanism of Lactobacillus leichmannii ribonucleotide reductase. Evidence for 3′ carbon-hydrogen bond cleavage and a unique role for coenzyme B12. J. Biol. Chem. 261 (1986) 3958–3964. [PMID: 3512563]
5.  Lawrence, C.C. and Stubbe, J. The function of adenosylcobalamin in the mechanism of ribonucleoside triphosphate reductase from Lactobacillus leichmannii. Curr. Opin. Chem. Biol. 2 (1998) 650–655. [DOI] [PMID: 9818192]
6.  Licht, S.S., Booker, S. and Stubbe, J. Studies on the catalysis of carbon-cobalt bond homolysis by ribonucleoside triphosphate reductase: evidence for concerted carbon-cobalt bond homolysis and thiyl radical formation. Biochemistry 38 (1999) 1221–1233. [DOI] [PMID: 9930982]
[EC 1.17.4.2 created 1972, modified 2017]
 
 
EC 1.19.1.1     
Accepted name: flavodoxin—NADP+ reductase
Reaction: reduced flavodoxin + NADP+ = oxidized flavodoxin + NADPH + H+
Other name(s): FPR
Systematic name: flavodoxin:NADP+ oxidoreductase
Comments: A flavoprotein (FAD). This activity occurs in some prokaryotes and algae that possess flavodoxin, and provides low-potential electrons for a variety of reactions such as nitrogen fixation, sulfur assimilation and amino acid biosynthesis. In photosynthetic organisms it is involved in the photosynthetic electron transport chain. The enzyme also catalyses EC 1.18.1.2, ferredoxin—NADP+ reductase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9029-33-8
References:
1.  McIver, L., Leadbeater, C., Campopiano, D.J., Baxter, R.L., Daff, S.N., Chapman, S.K. and Munro, A.W. Characterisation of flavodoxin NADP+ oxidoreductase and flavodoxin; key components of electron transfer in Escherichia coli. Eur. J. Biochem. 257 (1998) 577–585. [DOI] [PMID: 9839946]
2.  Leadbeater, C., McIver, L., Campopiano, D.J., Webster, S.P., Baxter, R.L., Kelly, S.M., Price, N.C., Lysek, D.A., Noble, M.A., Chapman, S.K. and Munro, A.W. Probing the NADPH-binding site of Escherichia coli flavodoxin oxidoreductase. Biochem. J. 352 (2000) 257–266. [PMID: 11085917]
3.  Wan, J.T. and Jarrett, J.T. Electron acceptor specificity of ferredoxin (flavodoxin):NADP+ oxidoreductase from Escherichia coli. Arch. Biochem. Biophys. 406 (2002) 116–126. [DOI] [PMID: 12234497]
4.  Bortolotti, A., Perez-Dorado, I., Goni, G., Medina, M., Hermoso, J.A., Carrillo, N. and Cortez, N. Coenzyme binding and hydride transfer in Rhodobacter capsulatus ferredoxin/flavodoxin NADP(H) oxidoreductase. Biochim. Biophys. Acta 1794 (2009) 199–210. [DOI] [PMID: 18973834]
5.  Bortolotti, A., Sanchez-Azqueta, A., Maya, C.M., Velazquez-Campoy, A., Hermoso, J.A., Medina, M. and Cortez, N. The C-terminal extension of bacterial flavodoxin-reductases: involvement in the hydride transfer mechanism from the coenzyme. Biochim. Biophys. Acta 1837 (2014) 33–43. [DOI] [PMID: 24016470]
6.  Skramo, S., Hersleth, H.P., Hammerstad, M., Andersson, K.K. and Rohr, A.K. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of a ferredoxin/flavodoxin-NADP(H) oxidoreductase (Bc0385) from Bacillus cereus. Acta Crystallogr. F Struct. Biol. Commun. 70 (2014) 777–780. [DOI] [PMID: 24915092]
[EC 1.19.1.1 created 2016]
 
 
EC 2.1.1.130     
Accepted name: precorrin-2 C20-methyltransferase
Reaction: S-adenosyl-L-methionine + precorrin-2 = S-adenosyl-L-homocysteine + precorrin-3A
For diagram of corrin and siroheme biosynthesis (part 2), click here
Systematic name: S-adenosyl-L-methionine:precorrin-2 C20-methyltransferase
Comments: This enzyme participates in the aerobic (late cobalt insertion) cobalamin biosynthesis pathway. See EC 2.1.1.151, cobalt-factor II C20-methyltransferase, for the equivalent enzyme that participates in the anaerobic cobalamin biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 131554-12-6
References:
1.  Roessner, C.A., Warren, M.J., Santander, P.J., Atshaves, B.P., Ozaki, S., Stolowich, N.J., Iida, K., Scott, A.I. Expression of Salmonella typhimurium enzymes for cobinamide synthesis. Identification of the 11-methyl and 20-methyl transferases of corrin biosynthesis. FEBS Lett. 301 (1992) 73–78. [DOI] [PMID: 1451790]
2.  Roessner, C.A., Spencer, J.B., Ozaki, S., Min, C., Atshaves, B.P., Nayar, P., Anousis, N., Stolowich, N.J., Holderman, M.T., Scott, A.I. Overexpression in Escherichia coli of 12 vitamin B12 biosynthetic enzymes. Protein Extr. Purif. 6 (1995) 155–163. [DOI] [PMID: 7606163]
3.  Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430–7440. [DOI] [PMID: 8226690]
[EC 2.1.1.130 created 1999]
 
 
EC 2.1.1.131     
Accepted name: precorrin-3B C17-methyltransferase
Reaction: S-adenosyl-L-methionine + precorrin-3B = S-adenosyl-L-homocysteine + precorrin-4
For diagram of corrin biosynthesis (part 3), click here and for mechanism of reaction, click here
Other name(s): precorrin-3 methyltransferase; CobJ
Systematic name: S-adenosyl-L-methionine:precorrin-3B C17-methyltransferase
Comments: The enzyme, which participates in the aerobic (late cobalt insertion) pathway of adenosylcobalamin biosynthesis, catalyses a crucial reaction where the tetrapyrrole ring contracts as a result of methylation of C-17. See EC 2.1.1.272, cobalt-factor III methyltransferase, for the corresponding enzyme that participates in the anaerobic cobalamin biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 152787-64-9
References:
1.  Scott, A.I., Roessner, C.A., Stolowich, N.J., Spencer, J.B., Min, C. and Ozaki, S.I. Biosynthesis of vitamin B12. Discovery of the enzymes for oxidative ring contraction and insertion of the fourth methyl group. FEBS Lett. 331 (1993) 105–108. [DOI] [PMID: 8405386]
2.  Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430–7440. [DOI] [PMID: 8226690]
[EC 2.1.1.131 created 1999]
 
 
EC 2.1.1.152     
Accepted name: precorrin-6A synthase (deacetylating)
Reaction: S-adenosyl-L-methionine + precorrin-5 + H2O = S-adenosyl-L-homocysteine + precorrin-6A + acetate
For diagram of corrin biosynthesis (part 3), click here and for mechanism of reaction, click here
Other name(s): precorrin-6X synthase (deacetylating); CobF
Systematic name: S-adenosyl-L-methionine:precorrin-5 C1-methyltransferase (deacetylating)
Comments: The enzyme, which participates in the aerobic (late cobalt insertion) cobalamin biosythesis pathway, catalyses two reactions -the methylation of carbon C1 of precorrin-5, and its deacetylation, forming precorrin-6A. See EC 2.1.1.195, cobalt-precorrin-5B (C1)-methyltransferase, for the C1-methyltransferase that participates in the anaerobic cobalamin biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430–7440. [DOI] [PMID: 8226690]
2.  Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390–412. [PMID: 12195810]
[EC 2.1.1.152 created 2004]
 
 
EC 2.6.1.52     
Accepted name: phosphoserine transaminase
Reaction: (1) O-phospho-L-serine + 2-oxoglutarate = 3-phosphooxypyruvate + L-glutamate
(2) 4-phosphooxy-L-threonine + 2-oxoglutarate = (3R)-3-hydroxy-2-oxo-4-phosphooxybutanoate + L-glutamate
For diagram of EC 2.6.1, click here, for diagram of serine biosynthesis, click here and for diagram of pyridoxal biosynthesis, click here
Other name(s): PSAT; phosphoserine aminotransferase; 3-phosphoserine aminotransferase; hydroxypyruvic phosphate-glutamic transaminase; L-phosphoserine aminotransferase; phosphohydroxypyruvate transaminase; phosphohydroxypyruvic-glutamic transaminase; 3-O-phospho-L-serine:2-oxoglutarate aminotransferase; SerC; PdxC; 3PHP transaminase
Systematic name: O-phospho-L-serine:2-oxoglutarate aminotransferase
Comments: A pyridoxal 5′-phosphate protein. This enzyme catalyses the second step in the phosphorylated pathway of serine biosynthesis [1,3] and the third step in pyridoxal 5′-phosphate biosynthesis in the bacterium Escherichia coli [3]. Pyridoxal 5′-phosphate is the cofactor for both activities and therefore seems to be involved in its own biosynthesis [4]. Non-phosphorylated forms of serine and threonine are not substrates [4]. The archaeal enzyme has a relaxed specificity and can act on L-cysteate and L-alanine as alternative substrates to O-phospho-L-serine [7].
Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, PDB, CAS registry number: 9030-90-4
References:
1.  Pizer, L.I. The pathway and control of serine biosynthesis in Escherichia coli. J. Biol. Chem. 238 (1963) 3934–3944. [PMID: 14086727]
2.  Hirsch, H. and Greenberg, D.M. Studies on phosphoserine aminotransferase of sheep brain. J. Biol. Chem. 242 (1967) 2283–2287. [PMID: 6022873]
3.  Zhao, G. and Winkler, M.E. A novel α-ketoglutarate reductase activity of the serA-encoded 3-phosphoglycerate dehydrogenase of Escherichia coli K-12 and its possible implications for human 2-hydroxyglutaric aciduria. J. Bacteriol. 178 (1996) 232–239. [DOI] [PMID: 8550422]
4.  Drewke, C., Klein, M., Clade, D., Arenz, A., Müller, R. and Leistner, E. 4-O-phosphoryl-L-threonine, a substrate of the pdxC(serC) gene product involved in vitamin B6 biosynthesis. FEBS Lett. 390 (1996) 179–182. [DOI] [PMID: 8706854]
5.  Zhao, G. and Winkler, M.E. 4-Phospho-hydroxy-L-threonine is an obligatory intermediate in pyridoxal 5′-phosphate coenzyme biosynthesis in Escherichia coli K-12. FEMS Microbiol. Lett. 135 (1996) 275–280. [PMID: 8595869]
6.  Baek, J.Y., Jun, D.Y., Taub, D. and Kim, Y.H. Characterization of human phosphoserine aminotransferase involved in the phosphorylated pathway of L-serine biosynthesis. Biochem. J. 373 (2003) 191–200. [PMID: 12633500]
7.  Helgadottir, S., Rosas-Sandoval, G., Soll, D. and Graham, D.E. Biosynthesis of phosphoserine in the Methanococcales. J. Bacteriol. 189 (2007) 575–582. [PMID: 17071763]
[EC 2.6.1.52 created 1972, modified 2006]
 
 
EC 2.7.1.177     
Accepted name: L-threonine kinase
Reaction: ATP + L-threonine = ADP + O-phospho-L-threonine
For diagram of corrin biosynthesis (part 6), click here
Other name(s): PduX
Systematic name: ATP:L-threonine O3-phosphotransferase
Comments: The enzyme is involved in the de novo synthesis of adenosylcobalamin. It is specific for ATP and free L-threonine. In the bacterium Salmonella enterica the activity with CTP, GTP, or UTP is 6, 11, and 3% of the activity with ATP.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Fan, C. and Bobik, T.A. The PduX enzyme of Salmonella enterica is an L-threonine kinase used for coenzyme B12 synthesis. J. Biol. Chem. 283 (2008) 11322–11329. [DOI] [PMID: 18308727]
2.  Fan, C., Fromm, H.J. and Bobik, T.A. Kinetic and functional analysis of L-threonine kinase, the PduX enzyme of Salmonella enterica. J. Biol. Chem. 284 (2009) 20240–20248. [DOI] [PMID: 19509296]
[EC 2.7.1.177 created 2012]
 
 
EC 2.8.4.1     
Accepted name: coenzyme-B sulfoethylthiotransferase
Reaction: methyl-CoM + CoB = CoM-S-S-CoB + methane
For diagram of methane biosynthesis, click here
Glossary: coenzyme B = CoB = N-(7-mercaptoheptanoyl)threonine 3-O-phosphate = N-(7-thioheptanoyl)-3-O-phosphothreonine
coenzyme M = CoM = 2-mercaptoethanesulfonate
2-(methylsulfanyl)ethanesulfonate = methyl-CoM
Other name(s): methyl-CoM reductase; methyl coenzyme M reductase
Systematic name: methyl-CoM:CoB S-(2-sulfoethyl)thiotransferase
Comments: This enzyme catalyses the final step in methanogenesis, the biological production of methane. This important anaerobic process is carried out only by methanogenic archaea. The enzyme can also function in reverse, for anaerobic oxidation of methane.The enzyme requires the hydroporphinoid nickel complex coenzyme F430. Highly specific for coenzyme B with a heptanoyl chain; ethyl CoM and difluoromethyl CoM are poor substrates. The sulfide sulfur can be replaced by selenium but not by oxygen.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, UM-BBD
References:
1.  Bobik, T.A., Olson, K.D., Noll, K.M. and Wolfe, R.S. Evidence that the heterodisulfide of coenzyme-M and 7-mercaptanoylthreonine phosphate is a product of the methylreductase reaction in Methanobacterium. Biochem. Biophys. Res. Commun. 149 (1987) 455–460. [DOI] [PMID: 3122735]
2.  Ellermann, J., Hedderich, R., Boecher, R. and Thauer, R.K. The final step in methane formation: investigations with highly purified methyl coenzyme M reductase component C from Methanobacterium thermoautotrophicum (strain Marburg). Eur. J. Biochem. 184 (1988) 63–68.
3.  Ermler, U., Grabarse, W., Shima, S., Goubeaud, M. and Thauer, R.K. Crystal structure of methyl coenzyme M reductase: The key enzyme of biological methane formation. Science 278 (1997) 1457–1462. [DOI] [PMID: 9367957]
4.  Signor, L., Knuppe, C., Hug, R., Schweizer, B., Pfaltz, A. and Jaun, B. Methane formation by reaction of a methyl thioether with a photo-excited nickel thiolate — a process mimicking methanogenesis in Archaea. Chemistry 6 (2000) 3508–3516. [PMID: 11072815]
5.  Scheller, S., Goenrich, M., Boecher, R., Thauer, R.K. and Jaun, B. The key nickel enzyme of methanogenesis catalyses the anaerobic oxidation of methane. Nature 465 (2010) 606–608. [DOI] [PMID: 20520712]
[EC 2.8.4.1 created 2001, modified 2011]
 
 
EC 3.1.3.73     
Accepted name: adenosylcobalamin/α-ribazole phosphatase
Reaction: (1) adenosylcobalamin 5′-phosphate + H2O = coenzyme B12 + phosphate
(2) α-ribazole 5′-phosphate + H2O = α-ribazole + phosphate
For diagram of the enzymeís role in corrin biosynthesis, click here
Other name(s): CobC; adenosylcobalamin phosphatase; α-ribazole phosphatase
Systematic name: adenosylcobalamin/α-ribazole-5′-phosphate phosphohydrolase
Comments: This enzyme catalyses the last step in the anaerobic (early cobalt insertion) pathway of adenosylcobalamin biosynthesis, characterized in Salmonella enterica [3]. It also participates in a salvage pathway that recycles cobinamide into adenosylcobalamin [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 251991-06-7
References:
1.  O'Toole, G.A., Trzebiatowski, J.R. and Escalante-Semerena, J.C. The cobC gene of Salmonella typhimurium codes for a novel phosphatase involved in the assembly of the nucleotide loop of cobalamin. J. Biol. Chem. 269 (1994) 26503–26511. [PMID: 7929373]
2.  Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390–412. [PMID: 12195810]
3.  Zayas, C.L. and Escalante-Semerena, J.C. Reassessment of the late steps of coenzyme B12 synthesis in Salmonella enterica: evidence that dephosphorylation of adenosylcobalamin-5′-phosphate by the CobC phosphatase is the last step of the pathway. J. Bacteriol. 189 (2007) 2210–2218. [DOI] [PMID: 17209023]
[EC 3.1.3.73 created 2004, modified 2011]
 
 
EC 3.5.1.90     
Accepted name: adenosylcobinamide hydrolase
Reaction: adenosylcobinamide + H2O = adenosylcobyric acid + (R)-1-aminopropan-2-ol
For diagram of cobinamide salvage pathways, click here
Other name(s): CbiZ; AdoCbi amidohydrolase
Systematic name: adenosylcobinamide amidohydrolase
Comments: Involved in the salvage pathway of cobinamide in archaea. Archaea convert adenosylcobinamide (AdoCbi) into adenosylcobinamide phosphate (AdoCbi-P) in two steps. First, the amidohydrolase activity of CbiZ cleaves off the aminopropanol moiety of AdoCbi yielding adenosylcobyric acid (AdoCby); second, AdoCby is converted into AdoCbi-P by the action of EC 6.3.1.10, adenosylcobinamide-phosphate synthase (CbiB).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 905988-16-1
References:
1.  Woodson, J.D. and Escalante-Semerena, J.C. CbiZ, an amidohydrolase enzyme required for salvaging the coenzyme B12 precursor cobinamide in archaea. Proc. Natl. Acad. Sci. USA 101 (2004) 3591–3596. [DOI] [PMID: 14990804]
[EC 3.5.1.90 created 2004]
 
 
EC 4.2.1.28     
Accepted name: propanediol dehydratase
Reaction: propane-1,2-diol = propanal + H2O
Other name(s): meso-2,3-butanediol dehydrase; diol dehydratase; DL-1,2-propanediol hydro-lyase; diol dehydrase; adenosylcobalamin-dependent diol dehydratase; propanediol dehydrase; coenzyme B12-dependent diol dehydrase; 1,2-propanediol dehydratase; dioldehydratase; propane-1,2-diol hydro-lyase; RiDD
Systematic name: propane-1,2-diol hydro-lyase (propanal-forming)
Comments: Two different forms of the enzyme have been described. One form requires a cobamide coenzyme, while the other is a glycyl radical enzyme. The cobamide-dependent enzyme has been shown to also dehydrate ethylene glycol to acetaldehyde.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9026-90-8
References:
1.  Abeles, R.H. and Lee, H.A., Jr. An intramolecular oxidation-reduction requiring a cobamide coenzyme. J. Biol. Chem. 236 (1961) 2347–2350. [PMID: 13680987]
2.  Lee, H.A. and Abeles, R.H. Purification and properties of dioldehydrase, and enzyme requiring a cobamide coenzyme. J. Biol. Chem. 238 (1963) 2367–2373. [PMID: 13929077]
3.  Forage, R.G. and Foster, M.A. Glycerol fermentation in Klebsiella pneumoniae: functions of the coenzyme B12-dependent glycerol and diol dehydratases. J. Bacteriol. 149 (1982) 413–419. [PMID: 7035429]
4.  LaMattina, J.W., Keul, N.D., Reitzer, P., Kapoor, S., Galzerani, F., Koch, D.J., Gouvea, I.E. and Lanzilotta, W.N. 1,2-Propanediol dehydration in Roseburia inulinivorans: structural basis for substrate and enantiomer selectivity. J. Biol. Chem. 291 (2016) 15515–15526. [DOI] [PMID: 27252380]
[EC 4.2.1.28 created 1965]
 
 
EC 4.2.1.30     
Accepted name: glycerol dehydratase
Reaction: glycerol = 3-hydroxypropanal + H2O
Other name(s): glycerol dehydrase; glycerol hydro-lyase; dhaB (gene name)
Systematic name: glycerol hydro-lyase (3-hydroxypropanal-forming)
Comments: Two different forms of the enzyme have been described. One form requires a cobamide coenzyme, while the other is a glycyl radical enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9077-68-3
References:
1.  Smiley, K.L. and Sobolov, M. A cobamide-requiring glycerol dehydrase from an acrolein-forming Lactobacillus. Arch. Biochem. Biophys. 97 (1962) 538–543. [DOI] [PMID: 14039344]
2.  Schneider, Z. and Pawelkiewicz, J. The properties of glycerol dehydratase isolated from Aerobacter aerogenes, and the properties of the apoenzyme subunits. Acta Biochim. Pol. 13 (1966) 311–328. [PMID: 5962440]
3.  Schneider, Z., Larsen, E.G., Jacobsen, G., Johnson, B.C. and Pawelkiewicz, J. Purification and properties of glycerol dehydrase. J. Biol. Chem. 245 (1970) 3388–3396. [PMID: 4989992]
4.  Forage, R.G. and Foster, M.A. Glycerol fermentation in Klebsiella pneumoniae: functions of the coenzyme B12-dependent glycerol and diol dehydratases. J. Bacteriol. 149 (1982) 413–419. [PMID: 7035429]
5.  O'Brien, J.R., Raynaud, C., Croux, C., Girbal, L., Soucaille, P. and Lanzilotta, W.N. Insight into the mechanism of the B12-independent glycerol dehydratase from Clostridium butyricum: preliminary biochemical and structural characterization. Biochemistry 43 (2004) 4635–4645. [PMID: 15096031]
[EC 4.2.1.30 created 1972]
 
 
EC 4.2.1.114     
Accepted name: methanogen homoaconitase
Reaction: (R)-2-hydroxybutane-1,2,4-tricarboxylate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate (overall reaction)
(1a) (R)-2-hydroxybutane-1,2,4-tricarboxylate = (Z)-but-1-ene-1,2,4-tricarboxylate + H2O
(1b) (Z)-but-1-ene-1,2,4-tricarboxylate + H2O = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
For diagram of the 2-aminoadipate pathway of L-lysine synthesis, click here
Glossary: cis-homoaconitate = (Z)-but-1-ene-1,2,4-tricarboxylate
(R)-homocitrate = (R)-2-hydroxybutane-1,2,4-tricarboxylate
homoisocitrate = (-)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): methanogen HACN
Systematic name: (R)-2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate-forming]
Comments: This enzyme catalyses several reactions in the pathway of coenzyme-B biosynthesis in methanogenic archaea. Requires a [4Fe-4S] cluster for activity. In contrast to EC 4.2.1.36, homoaconitate hydratase, this enzyme can catalyse both the dehydration of (R)-homocitrate to form cis-homoaconitate and the subsequent hydration reaction that forms homoisocitrate. In addition to cis-homoaconitate, the enzyme can also catalyse the hydration of the physiological substrates dihomocitrate and trihomocitrate as well as the non-physiological substrate tetrahomocitrate. cis-Aconitate and threo-DL-isocitrate cannot act as substrates, and (S)-homocitrate and trans-homoaconitate act as inhibitors of the enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Drevland, R.M., Jia, Y., Palmer, D.R. and Graham, D.E. Methanogen homoaconitase catalyzes both hydrolyase reactions in coenzyme B biosynthesis. J. Biol. Chem. 283 (2008) 28888–28896. [DOI] [PMID: 18765671]
[EC 4.2.1.114 created 2009]
 
 
EC 4.3.1.7     
Accepted name: ethanolamine ammonia-lyase
Reaction: ethanolamine = acetaldehyde + NH3
Other name(s): ethanolamine deaminase
Systematic name: ethanolamine ammonia-lyase (acetaldehyde-forming)
Comments: A cobalamin protein.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9054-69-7
References:
1.  Bradbeer, C. The clostridial fermentations of choline and ethanolamine. 1. Preparation and properties of cell-free extracts. J. Biol. Chem. 240 (1965) 4669. [PMID: 5846987]
2.  Bradbeer, C. The clostridial fermentations of choline and ethanolamine. II. Requirement for a cobamide coenzyme by an ethanolamine deaminase. J. Biol. Chem. 240 (1965) 4675–4681. [PMID: 5846988]
3.  Kaplan, B.H. and Stadtman, E.R. Ethanolamine deaminase, a cobamide coenzyme-dependent enzyme. I. Purification, assay, and properties of the enzyme. J. Biol. Chem. 243 (1968) 1787–1793. [PMID: 4297225]
[EC 4.3.1.7 created 1972]
 
 
EC 4.4.1.24     
Accepted name: (2R)-sulfolactate sulfo-lyase
Reaction: (2R)-3-sulfolactate = pyruvate + hydrogensulfite
Other name(s): Suy; SuyAB; 3-sulfolactate bisulfite-lyase; sulfolactate sulfo-lyase (ambigious); (2R)-3-sulfolactate bisulfite-lyase (pyruvate-forming)
Systematic name: (2R)-3-sulfolactate hydrogensulfite-lyase (pyruvate-forming)
Comments: Requires iron(II). This inducible enzyme participates in cysteate degradation by the bacterium Paracoccus pantotrophus NKNCYSA and in 3-sulfolactate degradation by the bacterium Chromohalobacter salexigens. The enzyme is specific for the (R) isomer of its substrate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 1256650-35-7
References:
1.  Graham, D.E. and White, R.H. Elucidation of methanogenic coenzyme biosyntheses: from spectroscopy to genomics. Nat. Prod. Rep. 19 (2002) 133–147. [PMID: 12013276]
2.  Rein, U., Gueta, R., Denger, K., Ruff, J., Hollemeyer, K. and Cook, A.M. Dissimilation of cysteate via 3-sulfolactate sulfo-lyase and a sulfate exporter in Paracoccus pantotrophus NKNCYSA. Microbiology 151 (2005) 737–747. [DOI] [PMID: 15758220]
3.  Denger, K. and Cook, A.M. Racemase activity effected by two dehydrogenases in sulfolactate degradation by Chromohalobacter salexigens: purification of (S)-sulfolactate dehydrogenase. Microbiology 156 (2010) 967–974. [DOI] [PMID: 20007648]
[EC 4.4.1.24 created 2006, modified 2011]
 
 
EC 5.3.3.20      
Transferred entry: 2-hydroxyisobutanoyl-CoA mutase. Now EC 5.4.99.64, 2-hydroxyisobutanoyl-CoA mutase
[EC 5.3.3.20 created 2016, deleted 2017]
 
 
EC 5.4.3.5     
Accepted name: D-ornithine 4,5-aminomutase
Reaction: D-ornithine = (2R,4S)-2,4-diaminopentanoate
Other name(s): D-α-ornithine 5,4-aminomutase; D-ornithine aminomutase
Systematic name: D-ornithine 4,5-aminomutase
Comments: A pyridoxal-phosphate protein that requires a cobamide coenzyme for activity.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, CAS registry number: 62213-30-3
References:
1.  Somack, R. and Costilow, R.N. Purification and properties of a pyridoxal phosphate and coenzyme B12 dependent D-α-ornithine 5,4-aminomutase. Biochemistry 12 (1973) 2597–2604. [PMID: 4711468]
[EC 5.4.3.5 created 1972 as EC 5.4.3.1, transferred 1976 to EC 5.4.3.5, modified 2003]
 
 
EC 5.4.3.7     
Accepted name: leucine 2,3-aminomutase
Reaction: (2S)-α-leucine = (3R)-β-leucine
Systematic name: (2S)-α-leucine 2,3-aminomutase
Comments: Requires a cobamide coenzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 59125-53-0
References:
1.  Freer, I., Pedrocchi-Fantoni, G., Picken, D.J. and Overton, K.H. Stereochemistry of the leucine 2,3-aminomutase from tissue-cultures of Andrographis paniculata. J. Chem. Soc. Chem. Commun. (1981) 80–82.
2.  Poston, J.M. Leucine 2,3-aminomutase, an enzyme of leucine catabolism. J. Biol. Chem. 251 (1976) 1859–1863. [PMID: 1270414]
3.  Poston, J.M. Coenzyme B12-dependent enzymes in potatoes: leucine 2,3-aminomutase and methylmalonyl-CoA mutase. Phytochemistry 17 (1976) 401–402.
[EC 5.4.3.7 created 1982]
 
 
EC 5.4.99.2     
Accepted name: methylmalonyl-CoA mutase
Reaction: (R)-methylmalonyl-CoA = succinyl-CoA
For diagram of the 3-hydroxypropanoate cycle, click here
Other name(s): methylmalonyl-CoA CoA-carbonyl mutase; methylmalonyl coenzyme A mutase; methylmalonyl coenzyme A carbonylmutase; (S)-methylmalonyl-CoA mutase; (R)-2-methyl-3-oxopropanoyl-CoA CoA-carbonylmutase [incorrect]
Systematic name: (R)-methylmalonyl-CoA CoA-carbonylmutase
Comments: Requires a cobamide coenzyme.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, PDB, UM-BBD, CAS registry number: 9023-90-9
References:
1.  Barker, H.A. Coenzyme B12-dependent mutases causing carbon chain rearrangements. In: Boyer, P.D. (Ed.), The Enzymes, 3rd edn, vol. 6, Academic Press, New York, 1972, pp. 509–537.
[EC 5.4.99.2 created 1961, modified 1983]
 
 
EC 5.4.99.13     
Accepted name: isobutyryl-CoA mutase
Reaction: 2-methylpropanoyl-CoA = butanoyl-CoA
Glossary: pivalate = 2,2-dimethylpropanoate
Other name(s): isobutyryl coenzyme A mutase; butyryl-CoA:isobutyryl-CoA mutase; icmA (gene name); icmB (gene name); icmF (gene name)
Systematic name: 2-methylpropanoyl-CoA CoA-carbonylmutase
Comments: This bacterial enzyme utilizes 5′-deoxyadenosylcobalamin as a cofactor. Following substrate binding, the enzyme catalyses the homolytic cleavage of the cobalt-carbon bond of AdoCbl, yielding cob(II)alamin and a 5′-deoxyadenosyl radical, which initiates the the carbon skeleton rearrangement reaction by hydrogen atom abstraction from the substrate. At the end of each catalytic cycle the 5′-deoxyadenosyl radical and cob(II)alamin recombine, regenerating the resting form of the cofactor. The enzyme is prone to inactivation resulting from occassional loss of the 5′-deoxyadenosyl molecule. Inactivated enzymes are repaired by the action of EC 2.5.1.17, cob(I)yrinic acid a,c-diamide adenosyltransferase, and a G-protein chaperone, which restore cob(II)alamin (which is first reduced to cob(I)alamin by an unidentified reductase) to 5′-deoxyadenosylcobalamin and load it back on the mutase. Some mutases are fused with their G-protein chaperone. These enzyme can also catalyse the interconversion of isovaleryl-CoA with pivalyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 116405-23-3
References:
1.  Brendelberger, G., Rétey, J., Ashworth, D.M., Reynolds, K., Willenbrock, F. and Robinson, J.A. The enzymic interconversion of isobutyryl and N-butyrylcarba(dethia)-coenzyme-A - a coenzyme-B12-dependent carbon skeleton rearrangement. Angew. Chem. Int. Ed. Engl. 27 (1988) 1089–1091.
2.  Ratnatilleke, A., Vrijbloed, J.W. and Robinson, J.A. Cloning and sequencing of the coenzyme B12-binding domain of isobutyryl-CoA mutase from Streptomyces cinnamonensis, reconstitution of mutase activity, and characterization of the recombinant enzyme produced in Escherichia coli. J. Biol. Chem. 274 (1999) 31679–31685. [DOI] [PMID: 10531377]
3.  Cracan, V., Padovani, D. and Banerjee, R. IcmF is a fusion between the radical B12 enzyme isobutyryl-CoA mutase and its G-protein chaperone. J. Biol. Chem. 285 (2010) 655–666. [DOI] [PMID: 19864421]
4.  Cracan, V. and Banerjee, R. Novel coenzyme B12-dependent interconversion of isovaleryl-CoA and pivalyl-CoA. J. Biol. Chem. 287 (2012) 3723–3732. [DOI] [PMID: 22167181]
5.  Jost, M., Born, D.A., Cracan, V., Banerjee, R. and Drennan, C.L. Structural basis for substrate specificity in adenosylcobalamin-dependent isobutyryl-CoA mutase and related acyl-CoA mutases. J. Biol. Chem. 290 (2015) 26882–26898. [DOI] [PMID: 26318610]
6.  Li, Z., Kitanishi, K., Twahir, U.T., Cracan, V., Chapman, D., Warncke, K. and Banerjee, R. Cofactor editing by the G-protein metallochaperone domain regulates the radical B12 enzyme IcmF. J. Biol. Chem. 292 (2017) 3977–3987. [DOI] [PMID: 28130442]
[EC 5.4.99.13 created 1992, revised 2017]
 
 
EC 5.4.99.63     
Accepted name: ethylmalonyl-CoA mutase
Reaction: (2R)-ethylmalonyl-CoA = (2S)-methylsuccinyl-CoA
Other name(s): Ecm
Systematic name: (2R)-ethylmalonyl-CoA CoA-carbonylmutase
Comments: The enzyme, characterized from the bacterium Rhodobacter sphaeroides, is involved in the ethylmalonyl-CoA pathway for acetyl-CoA assimilation. Requires coenzyme B12 for activity.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Erb, T.J., Retey, J., Fuchs, G. and Alber, B.E. Ethylmalonyl-CoA mutase from Rhodobacter sphaeroides defines a new subclade of coenzyme B12-dependent acyl-CoA mutases. J. Biol. Chem. 283 (2008) 32283–32293. [DOI] [PMID: 18819910]
[EC 5.4.99.63 created 2015]
 
 
EC 5.4.99.64     
Accepted name: 2-hydroxyisobutanoyl-CoA mutase
Reaction: 2-hydroxy-2-methylpropanoyl-CoA = (S)-3-hydroxybutanoyl-CoA
Glossary: 2-hydroxy-2-methylpropanoyl-CoA = 2-hydroxyisobutanoyl-CoA
Other name(s): hcmAB (gene names)
Systematic name: 2-hydroxy-2-methylpropanoyl-CoA mutase
Comments: The enzyme, characterized from the bacterium Aquincola tertiaricarbonis, uses radical chemistry to rearrange the positions of both a methyl group and a hydroxyl group. It consists of two subunits, the smaller one containing a cobalamin cofactor. It plays a central role in the degradation of assorted substrates containing a tert-butyl moiety.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Yaneva, N., Schuster, J., Schafer, F., Lede, V., Przybylski, D., Paproth, T., Harms, H., Muller, R.H. and Rohwerder, T. Bacterial acyl-CoA mutase specifically catalyzes coenzyme B12-dependent isomerization of 2-hydroxyisobutyryl-CoA and (S)-3-hydroxybutyryl-CoA. J. Biol. Chem. 287 (2012) 15502–15511. [DOI] [PMID: 22433853]
2.  Kurteva-Yaneva, N., Zahn, M., Weichler, M.T., Starke, R., Harms, H., Muller, R.H., Strater, N. and Rohwerder, T. Structural basis of the stereospecificity of bacterial B12-dependent 2-hydroxyisobutyryl-CoA mutase. J. Biol. Chem. 290 (2015) 9727–9737. [DOI] [PMID: 25720495]
[EC 5.4.99.64 created 2016 as EC 5.3.3.20, transferred 2017 to EC 5.4.99.64]
 
 
EC 6.3.2.31     
Accepted name: coenzyme F420-0:L-glutamate ligase
Reaction: GTP + coenzyme F420-0 + L-glutamate = GDP + phosphate + coenzyme F420-1
For diagram of coenzyme F420 biosynthesis, click here
Glossary: coenzyme F420 = N-(N-{O-[5-(8-hydroxy-2,4-dioxo-2,3,4,10-tetrahydropyrimido[4,5-b]quinolin-10-yl)-5-deoxy-L-ribityl-1-phospho]-(S)-lactyl}-γ-L-glutamyl)-L-glutamate
Other name(s): CofE-AF; MJ0768; CofE
Systematic name: L-glutamate:coenzyme F420-0 ligase (GDP-forming)
Comments: This protein catalyses the successive addition of two glutamate residues to cofactor F420 by two distinct and independent reactions. In the reaction described here the enzyme attaches a glutamate via its α-amine group to F420-0. In the second reaction (EC 6.3.2.34, coenzyme F420-1—γ-L-glutamate ligase) it catalyses the addition of a second L-glutamate residue to the γ-carboxyl of the first glutamate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Li, H., Graupner, M., Xu, H. and White, R.H. CofE catalyzes the addition of two glutamates to F420-0 in F420 coenzyme biosynthesis in Methanococcus jannaschii. Biochemistry 42 (2003) 9771–9778. [DOI] [PMID: 12911320]
2.  Nocek, B., Evdokimova, E., Proudfoot, M., Kudritska, M., Grochowski, L.L., White, R.H., Savchenko, A., Yakunin, A.F., Edwards, A. and Joachimiak, A. Structure of an amide bond forming F420:γ-glutamyl ligase from Archaeoglobus fulgidus — a member of a new family of non-ribosomal peptide synthases. J. Mol. Biol. 372 (2007) 456–469. [DOI] [PMID: 17669425]
[EC 6.3.2.31 created 2010]
 
 
EC 6.3.2.34     
Accepted name: coenzyme F420-1:γ-L-glutamate ligase
Reaction: GTP + coenzyme F420-1 + L-glutamate = GDP + phosphate + coenzyme γ-F420-2
For diagram of coenzyme F420 biosynthesis, click here
Glossary: coenzyme F420 = N-(N-{O-[5-(8-hydroxy-2,4-dioxo-2,3,4,10-tetrahydropyrimido[4,5-b]quinolin-10-yl)-5-deoxy-L-ribityl-1-phospho]-(S)-lactyl}-γ-L-glutamyl)-L-glutamate
Other name(s): F420:γ-glutamyl ligase; CofE-AF; MJ0768; CofE
Systematic name: L-glutamate:coenzyme F420-1 ligase (GDP-forming)
Comments: This protein catalyses the successive addition of two glutamate residues to cofactor F420 by two distinct and independent reactions. In the first reaction (EC 6.3.2.31, coenzyme F420-0—L-glutamate ligase) the enzyme attaches a glutamate via its α-amine group to F420-0. In the second reaction, which is described here, the enzyme catalyses the addition of a second L-glutamate residue to the γ-carboxyl of the first glutamate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Li, H., Graupner, M., Xu, H. and White, R.H. CofE catalyzes the addition of two glutamates to F420-0 in F420 coenzyme biosynthesis in Methanococcus jannaschii. Biochemistry 42 (2003) 9771–9778. [DOI] [PMID: 12911320]
2.  Nocek, B., Evdokimova, E., Proudfoot, M., Kudritska, M., Grochowski, L.L., White, R.H., Savchenko, A., Yakunin, A.F., Edwards, A. and Joachimiak, A. Structure of an amide bond forming F420:γ-glutamyl ligase from Archaeoglobus fulgidus — a member of a new family of non-ribosomal peptide synthases. J. Mol. Biol. 372 (2007) 456–469. [DOI] [PMID: 17669425]
[EC 6.3.2.34 created 2010]
 
 
EC 6.6.1.2     
Accepted name: cobaltochelatase
Reaction: ATP + hydrogenobyrinate a,c-diamide + Co2+ + H2O = ADP + phosphate + cob(II)yrinate a,c-diamide + H+
For diagram of the enzyme's role in corrin biosynthesis, click here
Other name(s): hydrogenobyrinic acid a,c-diamide cobaltochelatase; CobNST; CobNCobST; hydrogenobyrinic-acid-a,c-diamide:cobalt cobalt-ligase (ADP-forming)
Systematic name: hydrogenobyrinate-a,c-diamide:cobalt cobalt-ligase (ADP-forming)
Comments: This enzyme, which forms part of the aerobic (late cobalt insertion) cobalamin biosynthesis pathway, is a type I chelatase, being heterotrimeric and ATP-dependent. It comprises two components, one of which corresponds to CobN and the other is composed of two polypeptides, specified by cobS and cobT in Pseudomonas denitrificans, and named CobST [1]. Hydrogenobyrinate is a very poor substrate. ATP can be replaced by dATP or CTP but the reaction proceeds more slowly. CobN exhibits a high affinity for hydrogenobyrinate a,c-diamide. The oligomeric protein CobST possesses at least one sulfhydryl group that is essential for ATP-binding. See EC 4.99.1.3, sirohydrochlorin cobaltochelatase, for the cobaltochelatase that participates in the anaerobic cobalamin biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 81295-49-0
References:
1.  Debussche, L., Couder, M., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Assay, purification, and characterization of cobaltochelatase, a unique complex enzyme catalyzing cobalt insertion in hydrogenobyrinic acid a,c-diamide during coenzyme B12 biosynthesis in Pseudomonas denitrificans. J. Bacteriol. 174 (1992) 7445–7451. [DOI] [PMID: 1429466]
2.  Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390–412. [PMID: 12195810]
[EC 6.6.1.2 created 2004]
 
 


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