BIOELECTROCATALYSIS AT ELECTRODES COATED WITH ALCOHOL-DEHYDROGENASE, A QUINOHEMOPROTEIN WITH HEME-C SERVING AS A BUILT-IN MEDIATOR
BIOELECTROCATALYSIS AT ELECTRODES COATED WITH ALCOHOL-DEHYDROGENASE, A QUINOHEMOPROTEIN WITH HEME-C SERVING AS A BUILT-IN MEDIATOR
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DOI：
10.1016/0022-0728(93)87058-4
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发表时间：
1993-12-15
影响因子：
4.5
通讯作者：
NIKI, K
中科院分区：
文献类型：
--
作者：
IKEDA, T;KOBAYASHI, D;NIKI, K
乙醇脱氢酶(ADH)是一种含有吡咯喹啉醌(PQQ)和血红素c的细菌膜结合蛋白，它被吸附在金、银、玻碳或热解石墨电极上。吸附了ADH的所有电极都产生了氧化乙醇的阳极电流，其中吸附的ADH催化了乙醇的电解。其电催化行为可用酶电极上生物电催化的理论方程来描述，并用米氏常数K(M)和最大电流密度I(Max)/A两个量来表征。ADH镀金电极的电反射测量表明，吸附的ADH的血红素c与电极之间发生了电子转移。在此基础上，讨论了生物电催化的反应机理，提出了ADH的定向吸附是血红素部分与电极紧密接触，PQQ部分与底物反应部位朝向溶液。
Alcohol dehydrogenase (ADH), a bacterial membrane-bound protein containing pyrroloquinoline quinone (PQQ) and heme c was held by adsorption on electrodes of gold silver, glassy carbon, or pyrolytic graphite. All the electrodes with adsorbed ADH produced anodic currents which oxidized ethanol, in which the adsorbed ADH catalyzed the electrolysis of ethanol. The electrocatalysis behavior could be described by a theoretical equation for bioelectrocatalysis at an enzyme-coated electrode, and was characterized by two quantities, the Michaelis constant K(m), and maximum current density I(max)/A. Using electroreflectance measurements with an ADH-coated gold electrode it was revealed that electron transfer occurred between heme c of the adsorbed ADH and the electrode. On the basis of these results, the reaction mechanism of the bioelectrocatalysis is discussed and oriented adsorption of ADH is proposed with the heme c moiety being in close contact with the electrode and with the PQQ moiety, the site reacting with the substrate, facing toward the solution.