辣根过氧化物酶修饰电极的电化学研究

制备了考马斯亮蓝和多壁碳纳米管混合物修饰玻碳电极（CBB G-250/MWNT/GC），考察了固定在该修饰电极上的辣根过氧化物酶的电子转移情况。结果表明，辣根过氧化物酶在该电极上实现了稳定的直接电子转移反应，循环伏安图上出现了一对对称性良好的氧化还原峰。直接电子转移反应的表观速率常数k_s=4.68s^-1，式量电位E^0′几乎不随扫速（至少在20～270mV/s的扫速范围内）而变化，平均值为（-0.333±0.002）V（参比Ag/AgCl pH 7.0）。式量电位和pH的良好的线性关系表明该修饰电极上辣根过氧化物酶的直接电化学反应是有质子参与的。实验结果还证实了该修饰电极上酶对底物H₂O₂有良好的电催化活性。该方法可为生物传感器和生物燃料电池酶电极的制备提供基础数据。

Electrochemistry of horseradish peroxidase immobilized on a modified electrode

A mixture of Coomassie Brilliant Blue and a multi-walled carbon nanotube-modified glassy carbon electrode (CBB G-250/MWNT/GC) has been fabricated. Cyclic voltammetry shows a pair of well-defined and nearly symmetrical redox peaks, which correspond to the direct electron transfer of horseradish peroxidase (HRP). Apparant electron transfer rate constant (k_s) is 4.68s^-1 and formal redox potential E^0′is almost independent of the scan rate. The average value of E^0′ is (-0.333±0.002) V (vs. Ag/AgCl pH 7.0) in a phosphate buffer solution in the scan rate range 20-270?mV/s. The dependence of E^0′on the pH of the phosphate buffer solution confirms that the redox process involving protons. In addition, the results show that HRP on the surface of the modified electrode retains its bioelectrocatalytic activity for the reduction of H₂O₂. The proposed method is simple, making it potentially attractive for applications in biosensors and biofuel cells.