Coenzyme B (CoB)

Coenzyme B (CoB)
Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-mercaptoheptanoylthreoninephosphate. The molecule contains a thiol, which is its principal site of reaction.Coenzyme B reacts with 2-methylthioethanesulfonate (methyl-Coenzyme M, abbreviated CH3-S-CoM), to release methane in methanogenesis: 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:
CH3-S-CoM + HS-CoB -O2CCH=CHCO2- → -O2CCH2-CH2CO2- + CoB-S-S-CoM

Organism species: Pan-species (General)