Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA.
Annu Rev Microbiol. 2010;64:453-73. doi: 10.1146/annurev.micro.112408.134051.
Methane produced in the biosphere is derived from two major pathways. Conversion of the methyl group of acetate to CH(4) in the aceticlastic pathway accounts for at least two-thirds, and reduction of CO(2) with electrons derived from H(2), formate, or CO accounts for approximately one-third. Although both pathways have terminal steps in common, they diverge considerably in the initial steps and energy conservation mechanisms. Steps and enzymes unique to the CO(2) reduction pathway are confined to methanogens and the domain Archaea. On the other hand, steps and enzymes unique to the aceticlastic pathway are widely distributed in the domain Bacteria, the understanding of which has contributed to a broader understanding of prokaryotic biology.
生物圈中产生的甲烷源自两个主要途径。在乙酸分解途径中，醋酸盐的甲基转化为 CH(4)，至少占三分之二，而利用 H(2)、甲酸盐或 CO 衍生的电子还原 CO(2)，约占三分之一。尽管这两种途径在终末步骤上是共同的，但它们在初始步骤和能量守恒机制上有很大的差异。CO(2)还原途径特有的步骤和酶仅限于产甲烷菌和古菌域。另一方面，乙酸分解途径特有的步骤和酶广泛分布于细菌域，对其的了解有助于更广泛地了解原核生物生物学。
