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化学学报
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化学学报 ›› 2000, Vol. 58 ›› Issue (2): 235-239. 上一篇    下一篇

研究论文

磷酰化组氨酸形成六配位磷中间体的理论研究

谭波;赵玉芬;钟儒刚;戴乾圜   

  1. 清华大学化学系.北京(100084);清华大学生命科学院生命有机磷化学教育部重 点实验室;北京工业大学环境与能源工程学院癌化学与生物工程中心
  • 发布日期:2000-02-15

A theoretical study on the hexa-coordinate phosphorus intermediate of N-phosphorylhistidine

Tan Bo;Zhao Yufen;Zhong Rugang;Dai Qianhuan   

  1. Tsing Hua Univ, Dept Chem.Beijing(100084)
  • Published:2000-02-15

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用MNDO方法对磷酰化组氨酸磷上酯交换反应侧链咪唑基所参与的六配位磷机理进行了研究。六配位磷中间体形成后,使咪唑基对面的异丙氧基反应活性提高。当磷上酯交换反应发生时,异丙氧基离去和另一分子醇进攻磷,从咪唑基的对面发生,在能量上和空间上都是有利的。六配位磷机理比较好地解释了咪唑的催化作用。

关键词: 组氨酸, 磷酰化, 磷络合物, MNDO, 咪唑, 催化反应, 酯交换

The ester exchange reaction on phosphorus of N-phosphorylhistidine with primary alcohol has been studied by MNDO method. Due to the participation of imidazole group, a hexa-coordinate phosphorus intermediate was formed, in which the iso-propoxyl group opposite to the imidazole was more labile than the others and much easier to leave because the activation energy was lowered by 64kJ.mol^-^1. When this iso-propoxyl left, to a new form penta-coordinate phosphorus intermediate which then was to be attacked by an alcohol from the direction opposite to the imidazole group. The mechanism of hexa- coordinate phosphorus intermediate explains the catalytic effect of imidazole.

Key words: HISTIDINE, PHOSPHORYLATION, PHOSPHORUS COMPLEX, IMIDAZOLE, CATALYTIC REACTION, TRANSESTERIFICATION

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