Hydrogen Evolution from Soy-Bean Root Nodules
Hydrogen Evolution from Soy-Bean Root Nodules
复制标题
大豆根瘤的析氢
作者：
G. Hoch;Henry N. Little;Henry N. Little;R. Burris
Wilson和Burris 1综述了氢化酶参与生物固氮的证据，并提出了两个关于氢化酶参与固氮机制的工作假说。当Kamen和Gest发现Rhodocellum rubrum是一种固氮菌，并发现氮，无论是本身还是铵，都抑制其光生氢时，氢酶和固氮之间的关系进一步加强。来自巴氏梭菌的纯化氢化酶制剂在暴露于氮气时显示出相对于氢气、氧气、一氧化氮或真空下的光谱的光谱变化3。虽然根瘤细菌中氢化酶的最初报告没有得到后来对根瘤和根瘤细菌进行的更广泛试验的证实，但威尔逊最近报告说，与不存在氢相比，一种分解的大豆根瘤制剂在存在氢的情况下表现出光谱位移，这暗示了氢化酶的活性。在讨论固氮作用的比较生物化学时，常常把缺乏根瘤中氢化酶的明确证据作为一个不规则现象来引用。本来文提供的证据消除了这种不规则性，并进一步证明了固氮剂的一致性。
Wilson and Burris1 reviewed the evidence implicating hydrogenase in biological nitrogen fixation and suggested two working hypotheses for the mechanism of nitrogen fixation which included the participation of hydrogenase. The relation between hydrogenase and nitrogen fixation was strengthened further when Kamen and Gest2 discovered Rhodospirillum rubrum to be a nitrogen fixer and found that nitrogen, either as such or as ammonium, inhibited its photoproduction of hydrogen. Purified hydrogenase preparations from Clostridium pasteurianum have shown spectral changes when exposed to nitrogen relative to spectra under hydrogen, oxygen, nitric oxide or a vacuum3. Although the initial report4 of hydrogenase in root-nodule bacteria was not verified by later, more extensive tests5 with nodules and bacteria from nodules, Wilson6 recently has reported that a preparation of disintegrated soy-bean nodules exhibited spectral shifts in the presence, as compared to the absence, of hydrogen, suggestive of the activity of a hydrogenase. The absence of a clear demonstration of hydrogenase in nodules often has been cited in discussion of the comparative biochemistry of nitrogen fixation as an irregularity. Evidence from the present communication removes this irregularity and establishes a further point of uniformity among nitrogen-fixing agents.