NADH, a physiological electron donor in clostridial nitrogen fixation
NADH, a physiological electron donor in clostridial nitrogen fixation
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NADH，梭菌固氮中的生理电子供体
DOI：
10.1016/0014-5793(74)81000-8
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发表时间：
1974
期刊：
影响因子：
3.5
通讯作者：
N. Katz
中科院分区：
文献类型：
--
作者：
K. Jungermann;H. Kirchniawy;N. Katz
梭菌固氮酶以还原的铁氧还蛋白作为电子供体催化Ns至NH的ATP依赖性还原[1]。在N-生长的巴氏梭菌的无细胞提取物中，已经使用了几种系统来再生固氮酶反应中所需的还原的铁氧还蛋白：丙酮酸和丙酮酸-铁氧还蛋白氧化还原酶[2]，氢和氢化酶[3]以及甲酸和COZ-还原酶[4]。因此，丙酮酸、氢和甲酸通常被认为是梭菌固氮中的生理还原剂[5，6]。据报道，在几种梭菌中，NADH也通过NADH-铁氧还蛋白氧化还原酶还原铁氧还蛋白，然而，这些梭菌是NH生长的，因此缺乏固氮酶系统[7-lo]。由于NADH-铁氧还蛋白氧化还原酶尚未在NS生长的梭菌中得到证实，因此NADH似乎不被接受为梭菌NS-还原的电子供体，尽管这由初步证据[3]和理论考虑[11]所指示。在这次交流中，它表明，NADH-铁氧还蛋白氧化还原酶也存在于NS生长的Cl的无细胞提取物中。巴氏杆菌和
Clostridial nitrogenase catalyzes the ATP dependent reduction of Ns to NHs with reduced ferredoxin as electron donor [l]. In cell-free extracts of N,-grown Clostridium pasteuriunum several systems have been used to regenerate the reduced ferredoxin required in the nitrogenase reaction: pyruvate and pyruvate-ferredoxin oxidoreductase [2], hydrogen and hydrogenase [3] as well as formate and COZ-reductase [4]. Therefore pyruvate, hydrogen and formate are generally regarded as the physiological reductants in clostridial nitrogen fixation [5, 6]. NADH has also been reported to reduce ferredoxin via a NADH-ferredoxin oxidoreductase in several clostridia, which were however NHs-grown and thus devoid of the nitrogenase system [7-lo]. Since the NADH-ferredoxin oxidoreductase has not been demonstrated in Ns-grown clostridia as yet, NADH does not appear to be accepted as an electron donor for clostridial Ns-reduo tion, although this was indicated by preliminary evidence [3] and theoretical considerations [l I]. In this communication it is shown that NADH-ferredoxin oxidoreductase is present also in cellfree extracts of Ns-grown Cl. pasteurianum and