生物分子电催化的研究(Ⅲ)——血红蛋白在甲酚固紫修饰碳糊电极上的电催化

Studies on Electrocatalysis of Biomolecules at Modified Electrodes ( Ⅲ )——Catalytic Reduction of Hemoglobin at Chemically Modified Carbon Paste Electrode Containing Cresyl Fast Violet

血红蛋白是脊椎动物红细胞内的呼吸蛋白,但由于其电活性中心不容易暴露以及在电极表面强烈吸附造成电极的钝化,使得它在一般固体电极上的电子传递速率很慢,得不到有效的电流响应。有关血红蛋白在固体电极上的电化学行为的研究很少。众多的分析化学家都在积极寻求加速血红蛋白电子传递速度的途径,使蛋白质直接电化学分析成为可能。最近的研究表明,某些染料修饰电极可以促进血红蛋白的电极过程。

Hemoglobin exhibits such a slow rate of electron transfer that no useful current is observed at conventional electrodes, even with the application of relatively large overpotentials, for reasons ascribed to its extented three-dimensional structure and the resulting in accessibility of the electroactive center or to its adsorption onto and subsequent passivation of the electrode surface. Only a few papers dealing with the hemoglobin redox behaviour at solid electrodes have been reported. In the present work, the carbon paste electrode modified with a new mediator cresyl fast violet shows an electro-catalytic activity to the reduction of hemoglobin. In the medium of 0. 2 mol/L NaOAc-HOAc (pH = 5. 5), the oxidation and reduction peak potentials of the CME are Epa= - 0.14 V and Epc=- 0. 28 V (vs. SCE), respectively. The CME shows a good stability and a good current response for hemoglobin.