Sauer F D, Erfle J D, Mahadevan S
Biochem J. 1979 Jan 15;178(1):165-72. doi: 10.1042/bj1780165.
The membrane fraction isolated from broken cells of Methanobacterium ruminantium actively synthesized methane from CO2 and H2 without the addition of ATP or other cofactors. This activity was lost unless strictly anaerobic conditions were maintained throughout the isolation and incubation procedures. 3H2, but not 3H2O, was readily incorporated into methane. This indicates that hydrogen atoms are used in the formation of methane without the prior equilibration of protons with the water phase. Methylenetetrahydrofolate was shown to be converted into methane, but less efficiently than CO2. The evidence indicates that tetrahydrofolate derivatives may not be of primary importance in the formation of methane from CO2 and H2. No requirement for ATP in methanogenesis could be demonstrated. However, chemical reagents that can increase proton conductance in membranes and therby abolish the membrane electrical potential were also effective inhibitors of methanogenesis. It was postulated that, although the reduction of CO2 to methane by bacterial membranes may require energy derived from a transmembrane potential, this does not appear to be coupled to the intermediary synthesis of ATP.
从反刍甲烷杆菌破碎细胞中分离得到的膜组分，在不添加ATP或其他辅因子的情况下，能从CO₂和H₂中积极合成甲烷。除非在整个分离和培养过程中严格维持厌氧条件，否则该活性会丧失。³H₂能轻易掺入甲烷中，但³H₂O则不能。这表明氢原子在甲烷形成过程中被利用，而质子无需先与水相达到平衡。亚甲基四氢叶酸被证明可转化为甲烷，但效率低于CO₂。证据表明，四氢叶酸衍生物在由CO₂和H₂形成甲烷的过程中可能并非至关重要。未证实产甲烷过程中对ATP有需求。然而，能够增加膜中质子传导并因此消除膜电位的化学试剂也是产甲烷作用的有效抑制剂。据推测，尽管细菌膜将CO₂还原为甲烷可能需要源自跨膜电位的能量，但这似乎并未与ATP的中间合成相偶联。
