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讨论了共边双立方烷原子簇结构的固氮酶活性中心模型和固氮酶大多数底物μ_5-(η~2)型的络合方式。设计了合成FeMo co模型化合物的方法,重复性较好地得到FeMo co模型化合物粗结晶样品,这种样品具有所预期的Mo:Fe:S~*:Cl元素比、较高的催化活性和选择性,以及一定的组合固氮酶活性(约为FeMo co重组活性的3-6％)。根据这个模型,较圆满地阐明十多种底物的酶促反应机理,包括统一地解释了N_2,Ar,CO或CN~-四者分别存在下的酶促放H_2机理。根据实验和文献资料,提出比较精细的二步ATP驱动的电子传递机理,能说明Mortenson等观察到的ATP/2e比值随ATP/ADP比值变化的情况。扼要讨论了氨合成铁催化剂的原子簇活性中心本质,N_2化学吸附的可能模式,以及在铁催化剂上氨合成缔合式机理的一些论据。指出了固氮酶与铁催化剂在配位络合和催化作用的密切关系。
The central model of the activity of nitrogenase and the complexation of μ_5- (η ~ 2) type of most substrates of nitrogenase were discussed. The method of synthesizing FeMo co model compounds was designed and the coarse crystalline samples of FeMo co model compounds were obtained with good reproducibility. The sample has the expected Mo: Fe: S ~ *: Cl element ratio, high catalytic activity and selectivity As well as certain combinations of nitrogenase activity (about 3-6% of the FeMo co recombination activity). According to this model, the enzymatic reaction mechanism of more than ten substrates was elucidated satisfactorily, including the uniform explanation of the mechanism of enzymatic release of H 2 in the presence of N 2, Ar, CO or CN 4 -. Based on the experimental and literature data, a more elaborate two-step ATP-driven electron transport mechanism is proposed to illustrate the observed change in ATP / 2e ratio with the ATP / ADP ratio by Mortenson et al. In this paper, the nature of cluster centers, the possible modes of N 2 chemisorption, and some arguments about the association mechanism of ammonia synthesis on iron catalysts are briefly discussed. The close relationship between nitrogenase and iron catalyst in coordination complexation and catalysis is pointed out.