Electrochemical control of glucose oxidase-catalyzed redox reaction using an oil/water interface

Abstract

Glucose oxidase (GOD)-catalyzed electron transfers between some oxidants in nitrobenzene (NB) and glucose in water (W) were studied by cyclic voltammetry. When an electrically neutral compound, chloranil (CQ), was employed as the oxidant in NB, the enzymatic reaction could not be regulated because of the spontaneous transfer of CQ from NB to W. In this case, the voltammetric wave observed for the enzyme-catalyzed electron transfer was increased depending on the standing time until the voltage scan was started. However, when an ionic oxidant, dimethylferricenium ion (DiMFc⁺), was employed as the oxidant, the electrochemical control of the enzymatic reaction was achieved by controlling the interfacial transfer of DiMFc⁺, so that well-reproducible voltammograms could be obtained for different concentrations of DiMFc⁺ and for different scan rates. The voltammetric behaviors were successfully explained by a digital simulation based on the ion-transfer mechanism, which involves the interfacial transfer of DiMFc⁺ and the succeeding GOD-catalyzed electron transfer which occurs not heterogeneously at the interface, but homogeneously in the W phase.