IUBMB Enzyme Nomenclature


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-(phosphothreonine
CoM = coenzyme M = 2-sulfanylethane-1-sulfonate = 2-mercaptoethanesulfonate (deprecated)

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 [fumarate reductase (NADH)], EC [succinate dehydrogenase (ubiquinone)], and EC [fumarate reductase (quinol)].

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


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. [PMID: 9578488]

[EC created 2014 as EC, transferred 2014 to EC]

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