ALPHA-DEUTERIUM AND C-13 ISOTOPE EFFECTS FOR METHYL TRANSFER CATALYZED BY CATECHOL O-METHYLTRANSFERASE - SN2-LIKE TRANSITION-STATE

被引：142

作者：

HEGAZI, MF

BORCHARDT, RT

SCHOWEN, RL

机构：

[1] UNIV KANSAS,DEPT BIOCHEM,MCCOLLUM RES LABS,LAWRENCE,KS 66045

[2] UNIV KANSAS,DEPT CHEM,LAWRENCE,KS 66045

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 1979年 / 101卷 / 15期

关键词：

D O I：

10.1021/ja00509a052

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

The rate at near saturation of methylation of 3,4-dihydroxyacetophenone by S-adenosyl-L-methionine, catalyzed by rat-liver catechol O-methyltransferase at pH 7.58 and 37.00±0.05°C, is increased by deuteration of the methyl group (VCH3/VCD3= 0.83±0.05) and decreased by introduction ofl3C to the methyl group (V12/V13= 1.09±0.05). This shows the rate-determining step to be transfer of the methyl group, with an SN2-like transition state in which the methyl is located “symmetrically” and “tightly” between leaving group and nucleophile. © 1979, American Chemical Society. All rights reserved.

引用

页码：4359 / 4365

页数：7

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