Proton translocation coupled to methanogenesis from methanol + hydrogen in Methanosarcina barkeri

摘要

>Addition of methanol to resting cells of Methanosarcina barkeri incubated under an atmosphere of molecular hydrogen resulted in an acidification of the medium. This acidification was not observed when H₂ was replaced by N₂ or air, or when the uncoupler tetrachlorosalicylanilide was present. 2-Bromoethanesulfonate completely inhibited both methanogenesis and proton extrusion. N,N′-Dicyclohexylcarbodiimide, an inhibitor of the proton-translocating ATPase in M. barkeri, did not affect proton extrusion. Therefore, it could be concluded that proton translocation was coupled to the terminal methylcoenzyme M methylreductase reaction and that it was not due to an H+-translocating ATPase. A maximum value of 4 H+ translocated per CH₄ formed was calculated.