固氮酶中N_2和N_2O结合位的一种新的鉴定方法

A New Method Identifying the Binding Site of N 2 and N 2O in Nitrogenase

采用ＧＣ和ＧＣ－ＦＴＩＲ法，研究了Ｎ２和Ｎ２Ｏ对固氮酶催化Ｃ２Ｄ２还原活性及产物二氘代乙烯的反式－／顺式－异构体比值的影响，结果表明，Ｎ２和Ｎ２Ｏ均抑制Ｃ２Ｄ２的还原作用，并引起反式－／顺式－１，２－二氘代乙烯比值的增加．这一变化规律，与根据Ｃ２Ｈ２还原被Ｎ２和Ｎ２Ｏ抑制只发生在固氮酶铁钼辅基（ＦｅＭｏｃｏ）的笼内的假设而近似计算的结果相一致．实验结果和理论计算之间的一致性支持Ｎ２和Ｎ２Ｏ结合在ＦｅＭｏｃｏ的笼内。

The effects of N 2 and N 2O on C 2D 2 reduction activity and ratio of trans /cis 1,2 dideutroethylene in products catalyzed by nitrogenase have been studied using GC and GC FTIR measurements. The results showed that N 2 or N 2O can inhibit the C 2D 2 reduction,and result in the increase of the trans /cis ratio in CHD=CHD. The changes of the trans /cis ratio in 1,2 dideutroethylene are in line with the results from approximate calculations based on the hypothesis that the inhibition of C 2H 2 reduction by N 2 or N 2O takes place practically only inside the cage.The consistency between the experimental results and the approximate calculation supports the suggestions that N 2 and N 2O bound to inside the cage and mainly inhibit the C 2D 2 reduction inside the cage.