Chen J S, Blanchard D K
Biochem Biophys Res Commun. 1984 Jul 18;122(1):9-16. doi: 10.1016/0006-291x(84)90431-5.
Clostridium pasteurianum has two distinct hydrogenases, the bidirectional hydrogenase and the H2-oxidizing (uptake) hydrogenase. The H2-oxidizing hydrogenase has been purified (up to 970-fold) to a specific activity of 17,600 mumol H2 oxidized/min X mg protein (5 mM methylene blue) or 3.5 mumol H2 produced/min X mg protein (1 mM methyl viologen). The uptake hydrogenase has a Mr of 53,000 (one polypeptide chain). Depending upon how protein was measured, the Fe and S = contents (gatom/mol) were 4.7 and 5.2 (by the dye-binding assay) or 7.2 and 8.0 (by the Lowry method). Both reduced and oxidized forms of the enzyme gave electron paramagnetic resonance signals. The activation energy for H2-production and H2-oxidation by the uptake hydrogenase was 59.1 and 31.2 kJ/mol, respectively. In the exponential phase of growth, the ratio of uptake hydrogenase/bidirectional hydrogenase in NH3-grown cells was much lower than that in N2-fixing cells.
巴斯德梭菌有两种不同的氢化酶，即双向氢化酶和H2氧化（摄取）氢化酶。H2氧化氢化酶已被纯化（高达970倍），其比活性为17,600 μmol H2氧化/分钟×毫克蛋白（5 mM亚甲基蓝）或3.5 μmol H2产生/分钟×毫克蛋白（1 mM甲基紫精）。摄取氢化酶的相对分子质量为53,000（一条多肽链）。根据测定蛋白质的方法不同，铁和硫的含量（原子摩尔数/摩尔）分别为4.7和5.2（通过染料结合测定法）或7.2和8.0（通过洛瑞法）。该酶的还原形式和氧化形式均给出电子顺磁共振信号。摄取氢化酶产生H2和氧化H2的活化能分别为59.1和31.2 kJ/mol。在生长指数期，在以NH3为氮源生长的细胞中，摄取氢化酶/双向氢化酶的比值远低于固氮细胞中的该比值。
