Coenzyme B

Jump to: navigation, search
Template:Chembox E number
Coenzyme B
IUPAC name 2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid
3D model (JSmol)
ECHA InfoCard Lua error in Module:Wikidata at line 879: attempt to index field 'wikibase' (a nil value). Lua error in Module:Wikidata at line 879: attempt to index field 'wikibase' (a nil value).
Molar mass 343.333641
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-thioheptanoylthreoninephosphate.[1] The molecule contains a thiol, which is its principal site of reaction.

Coenzyme B reacts with 2-methylthioethanesulfonate, abbreviated CH3-S-CoM, to release methane in methanogenesis:[2]

CH3-S-CoM + HS-CoB → CH4 + CoB-S-S-CoM

This conversion is catalyzed by the enzyme methyl coenzyme M reductase, which contains cofactor F430 as the prosthetic group.

A related conversion that utilizes both HS-CoB and HS-CoM is the reduction of fumarate to succinate, catalyzed by fumarate reductase:[3]



  1. Noll KM, Rinehart KL, Tanner RS, Wolfe RS (1986). "Structure of component B (7-mercaptoheptanoylthreonine phosphate) of the methylcoenzyme M methylreductase system of Methanobacterium thermoautotrophicum". Proc. Natl. Acad. Sci. U.S.A. 83 (12): 4238–42. PMID 3086878.
  2. Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, volume 144, pages 2377-2406.
  3. Heim, S.; Künkel, A.; Thauer, R. K.; Hedderich, R. “Thiol:fumarate Reductase (Tfr) from Methanobacterium thermoautotrophicum: Identification of the Catalytic Sites for Fumarate Reduction and Thiol Oxidation” European Journal of Biochemistry 1998, volume 253, pages 292-299.