Wang Quanlin, Lu Gongxuan, Yang Baojun
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
Biosens Bioelectron. 2004 May 15;19(10):1269-75. doi: 10.1016/j.bios.2003.11.012.
Direct electrochemical and electrocatalytic behaviors of hemoglobin (Hb) immobilized on carbon paste electrode (CPE) by a silica sol-gel film derived from tetraethylorthosilicate (TEOS) were investigated for the first time. Hb/sol-gel film modified electrodes showed a pair of well-defined and nearly reversible cyclic voltammetric peaks for Hb Fe(III)/Fe(II) redox couple at about -0.312 V (versus Ag/AgCl) in a pH 7.0 phosphate buffer. The formal potential of Hb heme Fe(III)/Fe(II) couple varied linearly with the increase of pH in the range of 5.0-10.0 with a slope of 49.44 mV pH(-1), which suggests that a proton transfer is accompanied with each electron transfer (ET) in the electrochemical reaction. The immobilized Hb displayed the features of peroxidase and gave excellent electrocatalytic performance to the reduction of O2, NO2(-) and H2O2. The calculated apparent Michaelis-Menten constant was 8.98 x 10(-4)M, which indicated that there was a large catalytic activity of Hb immobilized on CPE by sol-gel film toward H2O2. In comparison with other electrodes, the chemically modified electrodes, used in this direct electrochemical study of Hb, are easy to be fabricated and rather inexpensive. Consequently, the Hb/sol-gel film modified electrode provides a convenient approach to perform electrochemical research on this kind of proteins. It also has potential use in the fabrication of the third generation biosensors and bioreactors.
首次研究了通过正硅酸四乙酯（TEOS）衍生的硅溶胶 - 凝胶膜固定在碳糊电极（CPE）上的血红蛋白（Hb）的直接电化学和电催化行为。在pH 7.0的磷酸盐缓冲液中，Hb/溶胶 - 凝胶膜修饰电极在约 -0.312 V（相对于Ag/AgCl）处显示出一对定义明确且近乎可逆的循环伏安峰，用于Hb Fe(III)/Fe(II)氧化还原对。Hb血红素Fe(III)/Fe(II)对的形式电位在5.0 - 10.0的pH范围内随pH升高呈线性变化，斜率为49.44 mV pH(-1)，这表明在电化学反应中每个电子转移（ET）伴随着一个质子转移。固定化的Hb表现出过氧化物酶的特性，并对O2、NO2(-)和H2O2的还原具有优异的电催化性能。计算得到的表观米氏常数为8.98×10(-4)M，这表明通过溶胶 - 凝胶膜固定在CPE上的Hb对H2O2具有很大的催化活性。与其他电极相比，在这项Hb的直接电化学研究中使用的化学修饰电极易于制备且成本相当低廉。因此, Hb/溶胶 - 凝胶膜修饰电极提供了一种方便的方法来对这类蛋白质进行电化学研究。它在第三代生物传感器和生物反应器的制造中也具有潜在用途。
