胞外高铁肌红蛋白还原酶电子传递活性位点的研究  

Study on the Active Site of MetMbase Electron Transport out of Cell

作　　者：王玮[1] 金邦荃[1] 陆艳[1] 刘瑾玲[1] 

机构地区：[1]南京师范大学食品科学与营养系,江苏南京210097

出　　处：《南京师大学报（自然科学版）》2009年第4期59-64,共6页Journal of Nanjing Normal University(Natural Science Edition)

基　　金：国家"863"科技攻关项目(2002AA242031-5);江苏省六大人才高峰项目(184080H10202);南京师范大学研究生优秀学位论文培育计划项目(181200000226)资助项目

摘　　要：以NADH为反应体系的启动剂,研究猪心肌提取液中高铁肌红蛋白还原酶(MetMbase)活性的表达,实验结果证实酶活性的表达依赖NADH启动,且0.2 mM NADH浓度可充分启动MetMbase活性的表达.研究还表明,ATP可全程抑制MetMbase呼吸链电子的传递,抑制酶的活性;NaN3通过阻断呼吸链第三位点电子传递来抑制酶活性的表达;而N-Ethylmaleimide能与MetMbase官能团巯基(-SH)瞬间结合并快速使酶活性丧失;二价金属离子能干扰活性的表达,Zn2+可促进MetMbase活性的表达;而Cu2+和Mg2+均抑制酶活性的表达,且Mg2+抑制强度大于Cu2+.金属螯合剂EDTA可掩蔽自由金属离子对MetMbase酶促反应的干扰,改善酶活性的表达.MetMbase extraction from porcine cardiac muscle was studied on its enzyme biochemical properties. For studying MetMbase active site, NADH, ATP, NaN3 , N-Ethylmaleimide and divalent metal ions were used as blockers or agonists in this research. The results showed that the expression of MetMbase activity depended on NADH starting. The most optinmm NADH concentration was 0. 2mM so that NADH was a promotor for MetMbase. In the reaction system, MetMbase activity was inhibited by the higher ATP level, because ATP could block electron transport in respiratory chain. At the third site MctMbase activity was blocked by NaN3. MetMbase was inactive through N-Ethylmaleimide bonding the sulfhydryl group（-SH） in enzyme protein structure at the moment. In addition, MetMbase activity was interfered by some divalent metal ions, such as Zn^2＋ , Cu^2＋ and Mg^2＋. MetMbase activity was increased by Zn^2＋ , while it was decreased by Cu^2＋ and Mg^2 ＋ . The inhibition of Mg^2 ＋ was more than that of Cu^2＋ . The free metal ions could be blocked by EDTA as a metal chelator. When EDTA was added in reaction system, MetMbase activity was expressed enough.

关 键 词：高铁肌红蛋白还原酶 电子传递 NADH NAN3 N-ETHYLMALEIMIDE 二价金属离子 

分 类 号：O629.8[理学—有机化学]