类酶催化反应中手性碳原子取代基的空间效应

Steric Effect of Chiral Carbon Replacing Group in the Similar Enzyme Reaction

结合手性碳原子取代基体积相对大小，及其产生的空间效应，研究了催化剂癸酰基－Ｌ－组氨酸（Ｄｅｃ－Ｌ－Ｈｉｓ）分别与Ｌ型Ｄ型底物即苄酯基－Ｌ－苯丙氨酸对硝基苯酚酯和苄酯基－Ｄ－苯丙氨酸对硝基苯酚酯（ＮＰＥ－Ｌ－ＣＢＺ－Ｐｈｅ和ＮＰＥ－Ｄ－ＣＢＺ－Ｐｈｅ）所形成中间物的稳定性，指出实验中催化剂立体选择性即Ｌ型底物占优势的原因，同时也说明所提机理的可靠性。

In the previous article,we first explored similar enzyme reaction with quantum chemistry and a reasonable pathway has been proposed.In this paper,we studied volume and steric effect chiral carbon replacing group in this reaction.The results show that complex of NPE L CBZ Phe and Dec L His is more stable than that of NPE D CBZ Phe and Dec L His.This is why catalyst has a great stereselectivity to L substrate in experiment. On the other hand,the reasonable pathway reported previously has been supported again.