Coenzyme M and methylcobalamin in methane biosynthesis: results of model studies.

Coenzyme M (2-mercaptoethanesulfonate, HS-CH2CH2SO3-) reacts with methylcobalamin nonenzymatically in the pH-range between 6 and 14 to yield the S-methyl derivative (CH3-S-CH2CH2SO3-). In addition, and also at lower pH, methane is produced by reductive cleavage of the Co-C bond. With methylcobaloximes as the methyl group donors, methane production predominates, with insignificant S-methylation. The initial rates of methane production from methylcobaloximes with coenzyme M as the reductant correlate with the rates of methane production from these substrates with active cell extracts of Methanobacterium M.o.H.