National Changhua University of Education Institutional Repository : Item 987654321/15142
English  |  正體中文  |  简体中文  |  全文筆數/總筆數 : 6507/11669
造訪人次 : 29938076      線上人數 : 547
RC Version 3.2 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜尋範圍 進階搜尋

請使用永久網址來引用或連結此文件: http://ir.ncue.edu.tw/ir/handle/987654321/15142

題名: Mechanistic Studies of Methane Biogenesis by Methyl-Coenzyme M Reductase: Evidence that Coenzyme B Participates in Cleaving the C-S Bond of Methyl-Coenzyme M
作者: Horng, Yih-Chern;Becker, Donald F.;Ragsdale, Stephen W.
貢獻者: 化學系
日期: 2001-10
上傳時間: 2013-01-07T02:15:46Z
出版者: American Chemical Society
摘要: Methyl-coenzyme M reductase (MCR), the key enzyme in methanogenesis, catalyzes methane formation from methyl-coenzyme M (methyl-SCoM) and N-7-mercaptoheptanoylthreonine phosphate (CoBSH). Steady-state and presteady-state kinetics have been used to test two mechanistic models that contrast in the role of CoBSH in the MCR-catalyzed reaction. In class 1 mechanisms, CoBSH is integrally involved in methane formation and in C-S (methyl-SCoM) bond cleavage. On the other hand, in class 2 mechanisms, methane is formed in the absence of CoBSH, which functions to regenerate active MCR after methane is released. Steady-state kinetic studies are most consistent with a ternary complex mechanism in which CoBSH binds before methane is formed, as found earlier [Bonacker et al. (1993) Eur. J. Biochem. 217, 587-595]. Presteady-state kinetic experiments at high MCR concentrations are complicated by the presence of tightly bound CoBSH in the purified enzyme. Chemical quench studies in which (14)CH(3)-SCoM is rapidly reacted with active MCRred1 in the presence versus the absence of added CoBSH indicate that CoBSH is required for a single-turnover of methyl-SCoM to methane. Similar single turnover studies using a CoBSH analogue leads to the same conclusion. The results are consistent with class 1 mechanisms in which CoBSH is integrally involved in methane formation and in C-S (methyl-SCoM) bond cleavage and are inconsistent with class 2 mechanisms in which CoBSH binds after methane is formed. These are the first reported pre-steady-state kinetic studies of MCR.
關聯: Biochemistry, 40(43): 12875-12885
顯示於類別:[化學系] 期刊論文

文件中的檔案:

檔案 大小格式瀏覽次數
index.html0KbHTML691檢視/開啟


在NCUEIR中所有的資料項目都受到原著作權保護.

 

DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 回饋