硒代蛋氨酸与铜离子的相互作用(英文)  

Interaction between Selenomethionine and Copper Ions

作　　者：王锐[1] 白燕[1] 梁志红[2] 刘莺[1] 黄莉莉[1] 郑文杰[1] 

机构地区：[1]暨南大学化学系,广州510632 [2]暨南大学分析测试中心,广州510632

出　　处：《物理化学学报》2010年第12期3225-3229,共5页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China (20771044);Natural Science Foundation of Guangdong Province, China (8251063201000008)~~

摘　　要：采用循环伏安法和库仑法研究了硒代蛋氨酸(SeMet)与铜离子的相互作用.当SeMet不存在时,铜离子在-132和71mV有一对氧化还原峰(峰Ⅴ,Ⅵ).当铜离子与SeMet共存时,配合物在14,128,271,-194mV有4个峰(峰Ⅰ,Ⅱ,Ⅲ,Ⅳ).扫描电位从600mV到-600mV时,Cu(Ⅱ)-(SeMet)2配合物在14mV时被还原为Cu(I)-SeMet配合物;Cu(Ⅰ)-SeMet配合物在-194mV被还原为Cu(0)和SeMet.由-600mV回扫时,还原产物被逐次氧化为Cu(Ⅰ)-SeMet配合物(128mV)和Cu(Ⅱ)-(SeMet)2配合物(271mV).同时发现Cu(Ⅰ)-SeMet配合物在电位-100mV至200mV间是稳定的,Cu(Ⅰ)的氧化还原过程被观察到.此外,采用毛细管电泳法测得二元Cu-SeMet配合物的稳定常数(K1和K2)分别为2.24×107和2.24×106.最后,推测Cu-SeMet配合物的结构为:在pH3.9时,铜离子通过Cu—Se和Cu—OCO键与SeMet发生配位作用;在生理条件时,铜离子通过Cu—N和Cu—OCO键与SeMet发生配位作用.The binary Cu-selenomethionine （SeMet） complex was investigated using voltammetry and chronocoulometry. A pair of peaks （Ⅴ,Ⅵ） were observed at -132 and 71 mV in the Cu（NO3）2 solution. When SeMet and Cu（NO3）2 coexisted, four peaks （Ⅰ,Ⅱ,Ⅲ,and Ⅳ） were observed at 14, 128, 271, and -194 mV, respectively. From the 600 to -600 mV potential scan, we observed that the Cu（Ⅱ）-（SeMet）2 complex was reduced to Cu（Ⅰ）-SeMet complex at 14 mV and then the Cu（I）-SeMet complex was reduced to Cu（0） and SeMet at -194 mV. After reaching -600 mV the potential was reversed and the reduced product was oxidized to the Cu（Ⅰ）-SeMet complex at 128 mV and Cu（Ⅱ）-（SeMet）2 complex at 271 mV. The Cu（Ⅰ）-SeMet complex was stable from about -100 to 200 mV and a redox process was observed for Cu（Ⅰ）. The stability constants of the binary Cu-SeMet complex, 2.24×10^7 （K1） and 2.24×10^6 （K2）, were determined by capillary electrophoresis. We proposed the structures of Cu-SeMet complexes： Copper coordinated with SeMet by the formation of Cu—Se and Cu—OCO bonds at pH 3.9 or by the formation of Cu—N and Cu—OCO bonds under physiological conditions.

关 键 词：铜离子 硒代蛋氨酸 电化学特性 配位结构 毛细管电泳 

分 类 号：O621.2[理学—有机化学]