Direct electron transfer-type bioelectrocatalytic interconversion of carbon dioxide/formate and NAD+/NADH redox couples with tungsten-containing formate dehydrogenase
Direct electron transfer-type bioelectrocatalytic interconversion of carbon dioxide/formate and NAD+/NADH redox couples with tungsten-containing formate dehydrogenase
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DOI：
10.1016/j.electacta.2017.01.112
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发表时间：
2017-02-20
影响因子：
6.6
通讯作者：
Kano, Kenji
中科院分区：
文献类型：
--
作者：
Sakai, Kento;Sugimoto, Yu;Kano, Kenji
来自扭脱甲基杆菌AM 1的分子量为170 kDa的含钨甲酸脱氢酶（FoDH 1）在溶液中催化甲酸（HCOO-）氧化为二氧化碳（CO2），NAD（+）作为天然电子受体。FoDH 1在平面电极上不产生任何直接电子转移（DET）型生物电催化波，但可以吸附在介孔碳电极上并与介孔碳电极连通。介孔结构的曲率效应似乎增加了具有适合于电化学通信的取向的酶的数量。然而，吸附进行缓慢的科琴黑修饰电极和催化电流密度仍然很低。最有可能的是，中孔的尺寸太小而不能有效地捕获FoDH 1。吸附的FoDH 1催化CO2/HCOO-和NAD（+）/NADH氧化还原对的DET型生物电催化相互转化。最有可能的是，位于酶表面附近的铁硫簇之一与介孔电极连通。当通讯有效进行时，FoDH 1表现为一种新型的底物的双向催化剂，因为FoDH 1可以实现快速的上坡分子内电子转移。FoDH 1中的非共价结合的黄素单甘肽（FMN）辅因子从一些FoDH 1分子中解离并吸附在介孔电极上，产生对称的表面限制氧化还原波。虽然吸附的FMN不能参与介导的电子转移（MET）型生物电催化，但游离的FMN在溶液中可作为介体参与HCOO-氧化的MET型生物电催化。(C)2017爱思唯尔有限公司版权所有
Tungsten-containing formate dehydrogenase (FoDH1) with a molecular mass of 170 kDa from Methylobacteriurn extorquens AM1 catalyzes the oxidation of formate (HCOO-) to carbon dioxide (CO2) with NAD(+) as a natural electron acceptor in solution. FoDH1 does not produce any direct electron transfer (DET)-type bioelectrocatalytic wave at planar electrodes, but can adsorb on and communicate with mesoporous carbon electrodes. The curvature effect of mesoporous structures seems to increase the number of enzymes with orientations suitable for electrochemical communication. However, adsorption proceeds slowly on Ketjen Black-modified electrode and the catalytic current density remains low. Most probably, the size of the mesopores is too small to effectively trap FoDH1. The adsorbed FoDH1 catalyzes DET-type bioelectrocatalytic interconversion of the CO2/HCOO- and NAD(+)/NADH redox couples. Most probably, one of the iron-sulfur clusters located near the enzyme surface communicates with mesoporous electrodes. When the communication proceeds effectively, FoDH1 behaves as a novel bidirectional catalyst for the substrates, since FoDH1 can realize fast uphill intramolecular electron transfer. The non-covarently bound flavin mononucleotide (FMN) cofactor in FoDH1 is dissociated from some FoDH1 molecules and adsorbs on the mesopofous electrode to give a symmetrical surface-confined redox wave. Although adsorbed FMN cannot participate in mediated electron transfer (MET)-type bioelectrocatalysis, dissociated FMN in solution works as a mediator for MET-type bioelectrdcatalysis of the HCOO- oxidation at planar electrodes. (C) 2017 Elsevier Ltd. All rights reserved.