NEw MODIFIED ELECTRODES FOR ELECTROCATALYTIC OXIDATION OF NADH BASED ON CONDUCTING POLYMERS

Abstract

The dehydrogenases are an importantclass of oxidoreductase enzymes, which depend on the cofactors B-nicotinamide adenine dinucleotide (NAD+)or B-nicotinamide adenine dinucleotide phosphate (NADP+)as electron acceptors. These enzymes catalyse the oxidation of specific substrates, with concomitant production of the reduced cofactor, NAD(P)H. In order to develop amperometric biosensors for determination of such sub- Strates, much researcheffort has been directed towards the electrochemical oxidation of NADH. However, direct oxidation of NADH requires a large overpotential (1) andis thought to involve radical intermediatesthat mayresult in electrode fouling (2).