IUBMB Enzyme Nomenclature


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-sulfanylethane-1-sulfonate = 2-mercaptoethanesulfonate (deprecated)
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, formate:CoB-CoM heterodisulfide,ferredoxin reductase. cf. EC, ferredoxin:CoB-CoM heterodisulfide reductase, EC, coenzyme F420:CoB-CoM heterodisulfide,ferredoxin reductase, and EC, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


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. [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. [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. [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. [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. [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. [PMID: 24039260]

[EC created 2017]

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