固氮酶活性中心FeMo-Cofactor对N_2活化方式的探讨

Discussion on the Activation Models of Dinitrogen by FeMo Cofactor in Nitrogenase

结合实验和理论计算的结果，讨论了固氮酶的活性中心铁钼辅基（ＦｅＭｏ－ｃｏ－ｆａｃｔｏｒ）对Ｎ２的各种活化方式，并在此基础上提出了一种新模型，即Ｎ２在ＦｅＭｏ－ｃｏｆａｃｔｏｒ的内部以“４Ｆｅ端基配位＋２Ｆｅ侧基配位”的方式被活化，Ｎ２的三重键完全断裂，断裂产生的两个含Ｎ的碎片分别偏向两侧的“窗口”，再在Ｈ的进攻下被还原为ＮＨ３，并分别从两侧的“窗口”离去。

On discussing some activation models of dinitrogen by the active center, FeMo cofactor of the nitrogenase based on experiments and theoretical calculations, a new activation model of dinitrogen has been suggested. In this model, the dinitrogen is coordinated to 4Fe and 2Fe atoms of FeMo cofactor in “end on” and “side on” modes respectively, and is activated inside the FeMo cofactor. Accompanying the complete cleavage of N N triple bond, both fragments containing N atom shift to the respective “window” on both sides of the FeMo cofactor and are reduced in the hydrogenation process to form NH 3 which get off from the nearby “windows”.