Usher D A
Proc Natl Acad Sci U S A. 1969 Mar;62(3):661-7. doi: 10.1073/pnas.62.3.661.
All the suggestions that have been made for the mechanism of action of ribonuclease can be classified into one or another of two classes, depending on the geometry of the displacement in the first step. Studies of related model compounds indicate that one of these two classes should include as a part of the mechanism a pentacoordinate intermediate, which undergoes pseudorotation before product can be formed. It is unlikely that the pseudorotation would be rate-limiting in the reaction of the normal substrate.
关于核糖核酸酶作用机制所提出的所有建议,根据第一步中取代反应的几何结构,可分为两类中的某一类。对相关模型化合物的研究表明,这两类中的一类应将五配位中间体作为作用机制的一部分,该中间体在形成产物之前会发生假旋转。在正常底物的反应中,假旋转不太可能是限速步骤。