ATP activation and properties of the methyl coenzyme M reductase system in Methanobacterium thermoautotrophicum

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Abstract
The requirement of ATP for the methyl coenzyme M methylreductase in extracts of M. thermoautotrophicum was catalytic; for each mole of ATP added, 15 mol of methane was produced from methyl coenzyme M [2-methylthio)ethanesulfonic acid]. Other nucleotide triphosphates partially replaced ATP in activation of the reductase. All components of the reaction were found in the supernatant fraction of cell extracts after centrifugation at 100,000 .times. g for 1 h; optimal reaction rates occurred at 65.degree. C, at a pH range of 5.6-6.0, and at concentrations at ATP and MgCl2 of 1 mM and 40 mM, respectively. Chloral hydrate, chloroform, nitrite, 2,4-dinitrophenol and viologen dyes (compounds known to inhibit methanogenesis from a variety of substrates) inhibited the conversion of methyl coenzyme M to methane. Methyl coenzyme M methylreductase was present in a variety of methanogens.