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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.
Cyclic voltammetry and coulometry were used to investigate the interaction of selenomethionine (SeMet) with copper ions. When SeMet is absent, the copper ions have a pair of redox peaks at -132 and 71 mV (peaks Ⅴ and Ⅵ) When the ions coexist with SeMet, the complexes have 4 peaks (peaks Ⅰ, Ⅱ, Ⅲ, Ⅳ) at 14,128,271 and -194mV.The Cu (Ⅱ) - (SeMet) Cu (I) -SeMet complex was reduced to Cu (0) and SeMet at -194 mV. The Cu-I (I) -SeMet complex was oxidized to Cu ) -SeMet complex (128mV) and Cu (Ⅱ) - (SeMet) 2 complex (271mV) .Cu (Ⅰ) -SeMet complex was also found to be stable at potentials between -100mV and 200mV. Redox process was observed.In addition, the stability constants (K1 and K2) of the binary Cu-SeMet complexes measured by capillary electrophoresis were 2.24 × 107 and 2.24 × 106 respectively.Finally, the structure of Cu-SeMet complexes Is as follows: At pH 3.9, Cu ions coordinate with SeMet via Cu-Se and Cu-OCO bonds; and Cu ions coordinate with SeMet through Cu-N and Cu-OCO bonds under physiological conditions.