魔芋多糖固定化肌红蛋白的直接电化学与电催化  

Direct Electrochemistry and Electrocatalysis of Myoglobin Entrapped in Konjac Glucomannan Films

作　　者：荣联清[1] 张志凌[1] 林毅[1] 谢娅妮[1] 庞代文[1] 

机构地区：[1]武汉大学化学与分子科学学院

出　　处：《分析化学》2006年第12期1683-1687,共5页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金资助项目(No.20305011)

摘　　要：用魔芋多糖（KGM）和N，N-二甲基甲酰胺（DMF）的加合物，将肌红蛋白（Mb）固定在玻碳电极（GCE）上，制备了稳定的Mb-KGM-DMF／GCE修饰电极，并研究了Mb在修饰电极上的直接电化学行为和电催化性能。该电极在pH=7．0的磷酸盐缓冲溶液（PBS）中，-0．38V（E^0）处有一对氧化还原峰，峰电位差△Ep=70mV，该峰正是Mb中血红素辅基Fe^Ⅲ／Fe^Ⅱ电对的氧化还原特征峰。在0．2—9．0V／s扫速的范围内，氧化还原峰峰电流大小和扫描速率成正比，呈现出表面控制行为。在pH为5．0—12．0的范围内，式电位和pH值呈线性关系，表明电子传递过程伴随着质子转移。同时，Mb—KGM—DMF／GCE修饰电极表现出良好的电催化性能，对氧、H2O2有显著的催化作用。在4．70～75．0μmol／L的范围内，其催化峰电流大小与H2O2的浓度有良好的线性关系，其线性回归方程i=0．127＋0．093C，r=0．9989，表观米氏常数为80．8μmol／L。Myoglobin （Mb） was immobilized on a glassy carbon electrode （GCE） by konjac glucomannan （KGM）-DMF conjugate to fabricate myoglobin modified electrode （Mb-KGM-DMF/GCE）. The behavior of direct electrochemistry and electrocatalysis of myoglobin on this modified electrode have been investigated. A pair of redox peaks with formal potential of -0.38 V and AEp of 70 mV was obtained on the modified electrode in phasphate buffer solution （PBS） （pH 7.0）, which resulted from the Fe^Ⅲ/Fe^Ⅱ couple of hemeprotein. The linear dependence of peak current on scan rate in range of 0.2 - 9.0 V/s showed a typical surface-controlled electrochemical process. The redox Bohr effect, a shift in the formal potential as a function of pH value from 5.0 to 12.0, indicated that Mb undergo proton-coupled electron transfer. Moreover, the obvious catalytic reduction of oxygen in solution and hydrogen peroxide by Mb was realized on Mb-KGM-DMF/ GCE. The catalytic current increased linearly with the concentration of H2O2 in the range of 4.70 - 75.0 μmol/L. And the apparent Michaelis-menten constant K,, was calculated to be 80.8 μmol/L.

关 键 词：肌红蛋白 魔芋多糖 修饰电极 直接电化学 电催化 

分 类 号：Q51[生物学—生物化学]