Methyl coenzyme M reductase (MCR) is an enzyme that plays a crucial role in the final step of methanogenesis, the process by which certain archaea produce methane. It catalyzes the reduction of methyl-coenzyme M (CH3-S-CoM) with the cofactor coenzyme B (HS-CoB) to produce methane (CH4) and a heterodisulfide (CoM-S-S-CoB).
