ENZYMATIC ELECTROCATALYSIS IN A MICELLAR ENVIRONMENT - GLUCOSE-OXIDASE CATALYSIS MEDIATED BY FERROCENE SOLUBILIZED BY ADDITION OF N-OCTYL-BETA-D-GLUCOSIDE

In the presence of the neutral n-octylglucoside surfactant the reduced form P of the ferrocene mediator is solubilized by micellization in a queous solution. Then it can be used in the mediation of the electroch emically driven oxidation of glucose catalyzed by glucose oxidase. The validity of the assumption that P is the only micellized species is a scertained by the analysis of the experimental results. The micellizat ion of the water-soluble ferrocenium Q can be neglected. The apparent diffusion coefficient D-P of ferrocene can be controlled by the micell e concentration while the diffusion coefficient D-Q of ferrocenium is only affected by the accompanying changes in the viscosity of the medi um. Accordingly, the kinetics of the enzymatic electrocatalysis, inves tigated by means of cyclic voltammetry, depends on D-P and the ratio d elta = D-P/D-Q. A thorough quantitative analysis of the observed behav ior enabled us to carry out the complete kinetic characterization of t he process and to show that all the rate constants involved in the enz yme kinetics are unaffected by the presence of the surfactant.