在存在光供体的情况下，固氮酶中电子转移各阶段的动力学。
Kinetics of all stages of electron transfer in nitrogenase in the presence of a photodonor.
作者信息
Syrtsova L A, Nadtochenko V A, Timofeeva E A
机构信息
Institute of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region, 142432, Russia.
出版信息
Biochemistry (Mosc). 1998 Aug;63(8):1007-13.
A photodonor is considered as an alternative electron donor for nitrogenase. The kinetic mechanism of nitrogenase turnover is discussed. The turnover is initiated by the transfer of an electron to the enzyme and results in formation of a substrate molecule. The effective rate constant of concerted transfer of the first and the second electron from Av2 (Fe-protein) to Av1 (Mo-Fe-protein) and the rate constant of transfer of the second electron are 70 +/- 7 and 116 +/- 10 sec-1, respectively. The rate constant of the rate-limiting reaction--MgADP release during formation of the superreduced state of Av1 (*Av12-)--is 12 +/- 2 sec-1. Nitrogenase (E) states in complex E.N2 on binding and reduction of nitrogen are: E2, E4, E6 (2, 4, and 6 electrons).
光供体被认为是固氮酶的替代电子供体。本文讨论了固氮酶周转的动力学机制。周转由电子向酶的转移引发，并导致底物分子的形成。从Av2（铁蛋白）向Av1（钼铁蛋白）协同转移第一个和第二个电子的有效速率常数以及第二个电子的转移速率常数分别为70±7和116±10秒⁻¹。限速反应——Av1超还原态（*Av1²⁻）形成过程中MgADP释放——的速率常数为12±2秒⁻¹。在结合和还原氮时，复合物E·N₂中的固氮酶（E）状态为：E2、E4、E6（2、4和6个电子）。
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