辣根过氧化物酶的电化学固定化及其对H_2O_2的生物电催化还原作用

利用电化学固定化方法制备了聚吡咯／辣根过氧化物酶（ＰＰ／ＨＲＰ）膜电极，并研究了其电化学行为。在除氧的磷酸盐缓冲液介质中，ＰＰ／ＨＲＰ电极加速Ｈ_２Ｏ_２的还原，归因于酶加成物的直接电子传递。探索ＨＲＰ与电子传递体Ｋ４Ｆｅ（ＣＮ）６在聚吡咯（ＰＰ）膜中的同时固定化条件及其膜电极的电化学行为，实验证实，Ｋ_４Ｆｅ（ＣＮ）_６在酶膜中的存在使得Ｈ_２Ｏ_２的还原电位强烈正移，在－０．０５Ｖ的工作电位下能对Ｈ_２Ｏ_２进行检测，相应的电极过程可用间接氧化还原催化机理解释。

Electrochemical Immobilization of Horse-Radis Peroxidase and Its Bioelectrocatalysis in H_2O_2 Redudion

With electropolymerization of pyrrole,horse-radish peroxidase(HRP) was immobilized in the polypyrrole matrix to construct PP/HRP enzyme electrode,and its electrochemical behaviour was studied.In the deoxygenated phosphate buffer,the PP/HRP electrode showed an accelerated H_2O_2 reduction,which was attributed to the direct electron transfer of the adduct of HRP with H_2O_2.The simultaneous immobilization of HRP and K_4Fe(CN)_6 into the polypyrrole(PP) polymer and the electrochemical behaviour of as-formed enzyme electrodes were investigated.It was confirmed that,the existence of K_4Fe(CN)_6 in the polymer enabled the reduction potential of H_2O_2 to strongly shift to positive so that H_2O_2 could be detected at-0.05 V.The related process was explained in terms of indirect redox catalysis.