Electrocatalytic oxidation of D-gluconate at a ubiquinone-mixed carbon paste electrode with an immobilized layer of D-gluconate dehydrogenase from bacterial membranes.

Abstract

D-Gluconate dehydrogenase (EC. 1.1.99.3) from Pseudomonas fluorescens was immobilized on the surface of a ubiquinone-mixed carbon paste electrode by irreversible adsorption. This electrode could oxidize D-gluconate electrocatalytically, with ubiquinone serving as an electron transfer mediator between the carbon paste electrode and the immobilized enzyme. The catalytic oxidation current observed with this electrode was analyzed as a function of the concentration of D-gluconate, the amount of mixed ubiquinone in the carbon paste electrode and the potential applied to the electrode. The results were explained by the theory of the catalytic current at an enzyme-modified electrode with an electron transfer mediator. The parameters characterizing the current response of the electrode to D-gluconate were determined.