溶菌酶在裸金电极和巯基乙酸或正十二硫烷基醇修饰金电极上的吸附  

Adsorption of Lysozyme onto Bare and Thioglycolic Acid or n-Dodecanethiol Modified Au Electrodes

作　　者：张友玉[1] 谢青季[1] 袁玉[1] 姚守拙[1] 

机构地区：[1]湖南师范大学化学研究所,长沙410081

出　　处：《应用化学》2002年第1期4-9,共6页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金 ( 2 990 5 0 0 2 );湖南省中青年科技基金 ( 98JZY2 16 8)资助项目

摘　　要：用石英晶体阻抗和电化学阻抗联用技术实时监测了溶菌酶在金电极和巯基乙酸或正十二硫醇修饰金电极上的吸附过程 .得到并讨论了等效电路参数、压电石英晶体谐振频率及双电层电容等参数的现场响应 .以两步骤连串反应机理分析溶菌酶吸附动力学 .结果表明 ,溶菌酶在电极表面的作用分吸附和重排 2个过程 ,双电层电容对吸附分子的重排过程更加敏感 .考察了电极表面亲水性对溶菌酶吸附的影响 ,测定了溶菌酶吸附前后 Fe( CN) 3 - 6/Fe( CN) 4- 6氧化还原反应标准速率常数和电荷传递电阻 .结果表明 ,溶菌酶在电极上的吸附量随电极表面疏水性增强而增大 ,随电极电位变正而减小 .溶菌酶在电极上的吸附使 Fe( CN) 3 - 6/Fe( CN) 4- 6电对电极反应的反应标准速率常数下降 ,电荷传递电阻增大 ,显著地降低了 Fe( CN) 3 - 6/Fe( CN) 4- 6电对的可逆性 .The process of adsorption of lysozyme onto bare and thioglycolic acid or n-dodecanethiol modified Au electrodes in a phosphate buffer (pH=7.3) solution has been investigated in situ using an electrochemical quartz crystal impedance system(EQCIS). Equivalent circuit parameters and resonance frequencies in piezoelectric quartz crystal(PQC) resonance as well as the electrical double layer capacitances were obtained and analyzed. A scheme of two consecutive reactions occurring at the interface was used to analyze the adsorption kinetics, suggesting that the double layer capacitance is more sensitive to the rearrangement of the adsorbed protein molecules compared with the resonance frequency. The effect of potential and hydrophilicity of electrode surface on the lysozyme adsorption was investigated. It is found that a more negative potential resulted in a larger responses of PQC resonance and the amount of adsorbed lysozyme on a hydrophobic surface was larger than that on a hydrophilic one. The standard heterogeneous rate constants of ferricyanide/ferrocyanide and charge transfer resistance before and after the lysozyme adsorption were determined. Decrease in standard heterogeneous rate constants of ferricyanide/ferrocyanide and increase in charge transfer resonance were observed after the lysozyme adsorption, showing that the reversibility of ferricyanide/ferrocyanide redox reaction was decreased.

关 键 词：溶菌酶 吸附 金电极 电化学石英晶体阻抗系统 巯基乙酸 正十二硫醇 电极反应 修饰电极 六氰合铁离子 

分 类 号：Q556.2[生物学—生物化学] O646.5[理学—物理化学]