Structure and function of methyl-coenzyme M reductase and of factor F430 in methanogenic bacteria

Summary Methyl-Coenzyme M is an intermediate in methane formation from CO 2 , formate, methanol, methylamines and acetate. The formation of methane from methyl-CoM is an exergonic reaction, which in the cell is coupled with the phosphorylation of ADP. Methyl-CoM reductase is one of the components involved in the catalysis of this reaction. The prosthetic group of the reductase is factor F430, which is a nickel porphinoid. In recent years methyl-CoM reductase has been studied extensively. Here two new findings are emphasized: (i) purified enzyme preparations catalyze the reduction of methyl-CoM to methane with dithiols as electron donors, (ii) the enzyme exhibits an EPR detectable nickel signal.