Shan Dan, Wang Shanxia, Zhu Daobin, Xue Huaiguo
School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
Bioelectrochemistry. 2007 Nov;71(2):198-203. doi: 10.1016/j.bioelechem.2007.04.007. Epub 2007 May 21.
The direct electrochemistry of hemoglobin (Hb) immobilized in polyacrylonitrile (PAN) modified glassy carbon electrode was described. The protein-PAN film exhibited a pair of well-defined and quasi-reversible cyclic voltammetric peaks for Hb Fe(III)/Fe(II) redox couple 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 5.0-9.0 with a slope of 54 mV pH(-1), which implied that a proton transfer was accompanied with each electron transfer in the electrochemical reaction. Position of Soret absorption band of Hb-PAN film suggested that the Hb kept its secondary structure similar to its native state in the PAN matrix. The Hb in PAN matrix acted as a biologic catalyst to catalyze the reduction of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H(2)O(2) concentration ranging from 8.3 x 10(-6) to 5 x 10(-4) mol L(-1) with a detection limit of 8.3 x 10(-6) mol L(-1) at 3 sigma. The apparent Michaelis-Menten constant K(M)(app) for H(2)O(2) sensor was estimated to be 0.9 mmol L(-1).
描述了固定在聚丙烯腈（PAN）修饰玻碳电极上的血红蛋白（Hb）的直接电化学。在pH 7.0的磷酸盐缓冲液中，蛋白质-PAN膜对Hb Fe(III)/Fe(II)氧化还原对呈现出一对定义明确且准可逆的循环伏安峰。Hb血红素Fe(III)/Fe(II)电对的形式电位在5.0 - 9.0范围内随pH升高呈线性变化，斜率为54 mV pH(-1)，这表明在电化学反应中每个电子转移都伴随着一个质子转移。Hb-PAN膜的Soret吸收带位置表明Hb在PAN基质中保持其与天然状态相似的二级结构。PAN基质中的Hb作为生物催化剂催化过氧化氢的还原。电催化响应在8.3×10(-6)至5×10(-4) mol L(-1)的过氧化氢浓度范围内呈线性依赖关系，在3σ时检测限为8.3×10(-6) mol L(-1)。H(2)O(2)传感器的表观米氏常数K(M)(app)估计为0.9 mmol L(-1)。
