期刊
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
卷 501, 期 2, 页码 207-213出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.abb.2010.06.014
关键词
Oxidase; Flavoprotein; Kinetics; Mechanism; Reductive half-reaction; Choline
资金
- US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-ACO2-98CH10886]
The oxidation of choline catalyzed by choline oxidase includes two reductive half-reactions where FAD is reduced by the alcohol substrate and by an aldehyde intermediate transiently formed in the reaction Each reductive half-reaction is followed by an oxidative half-reaction where the reduced Flavin is oxidized by oxygen Here, we have used mutagenesis to prepare the Ser101Ala mutant of choline oxidase and have investigated the impact of this mutation on the structural and kinetic properties of the enzyme The crystallographic structure of the Ser101Ala enzyme indicates that the only differences between the mutant and wild-type enzymes are the lack of a hydroxyl group on residue 101 and a more planar configuration of the flavin in the mutant enzyme Kinetics established that replacement of Ser101 with alanine yields a mutant enzyme with increased efficiencies in the oxidative half-reactions and decreased efficiencies in the reductive half-reactions This is accompanied by a significant decrease in the overall rate of turnover with choline Thus, this mutation has revealed the importance of a specific residue for the optimization of the overall turnover of choline oxidase, which requires fine-tuning of four consecutive half-reactions for the conversion of an alcohol to a carboxylic acid (C) 2010 Elsevier Inc All rights reserved
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据