1989 Volume 38 Issue 11 Pages 583-588
Quinoproteins (fructose-, glycerol-, polyamine-, alcohol- and glucosedehydrogenase) were immobilized on carbon paste electrodes by covering the latter with a dialysis membrane. Artificial electron acceptors for the enzymes such as ferricyanide served as mediators for the electron transfer coupling between the electrodes and the quinoproteins immobilized on them. Thus, the quinoprotein-modified electrodes could electrolytically oxidize the substrates. A fructose sensor based on this principle of current response was constructed. Gluconatedehydrogenase, a flavoprotein, from bacterial membranes and ubiquinone were co-immobilized on the basal plane of a pyrolytic graphite electrode by irreversible adsorption. This electrode showed steady-state current response to the substrate due to the electro-enzymic reaction with ubiquinone as a mediator. The electrode was used for voltammetric measurement of the substrate at higher sensitivity, where the reduced form of ubiquinone was preaccumulated by the enzymic reaction prior to electrochemical measurement.
