Ragsdale S W, Ljungdahl L G, DerVartanian D V
Biochem Biophys Res Commun. 1983 Sep 15;115(2):658-65. doi: 10.1016/s0006-291x(83)80195-8.
The nickel-containing CO dehydrogenases from Acetobacterium woodii and Clostridium thermoaceticum were studied by EPR spectroscopy in order to define the components involved in the EPR spectrum obtained by reaction of the enzymes with the substrate, CO. Using isotopic substitution techniques, these experiments unequivocally establish that a nickel-carbon species is involved in the g = 2.08, 2.02 EPR signal. Comparing the 61Ni- and 59Ni-substituted enzymes, the g = 2.08 component of the resonance was found to be mainly due to nickel with a smaller contribution by the carbon species. Reaction of the CO dehydrogenase with [13C]CO versus [12C]CO showed that a carbon species, formed from CO, was the major contributor to the g = 2.02 EPR signal. In addition, the oxidized CO dehydrogenase was found to exhibit a Ni (III) EPR signal analogous to that of the hydrogenases from the methanogenic and sulfate-reducing bacteria.
为了确定伍氏醋酸杆菌和热醋酸梭菌中含镍的一氧化碳脱氢酶与底物一氧化碳反应所获得的电子顺磁共振（EPR）谱中涉及的成分，采用EPR光谱对这些酶进行了研究。利用同位素取代技术，这些实验明确证实了一种镍 - 碳物质与g = 2.08、2.02的EPR信号有关。通过比较61Ni和59Ni取代的酶，发现共振的g = 2.08成分主要归因于镍，碳物质的贡献较小。一氧化碳脱氢酶与[13C]CO和[12C]CO反应表明，由CO形成的一种碳物质是g = 2.02 EPR信号的主要贡献者。此外，发现氧化态的一氧化碳脱氢酶表现出与产甲烷菌和硫酸盐还原菌中的氢化酶类似的Ni(III) EPR信号。
