A comparative study of different adenine derivatives for the electrocatalytic oxidation of β-nicotinamide adenine dinucleotide

The electrochemical oxidation of the adenine moiety in different adenine derivatives, including adenosine, adenosinemonophosphate (AMP), adenosinediphosphate (ADP) and adenosinetriphosphate (ATP), has been studied at pyrolytic graphite electrodes in aqueous solution in the pH range 5–11. All these compounds yield strongly adsorbed electroactive oxidation products with reversible behavior and formal potentials close to 0 V at pH 9.0. These oxidation products show strong electrocatalytic activity for the oxidation of the reduced form of β-nicotinamide adenine dinucleotide (NADH). The electrochemical properties of the electrocatalyst obtained by oxidation of the corresponding parent nucleotide were investigated by cyclic voltammetry. The influence of the structure of the parent compound on the electrocatalytic activity of the corresponding product toward NADH oxidation was studied also. The kinetics of the electrocatalytic reactions were evaluated from rotating disk electrode measurements. These modified graphite electrodes can be used as NADH transducers in biosensors for substrates of dehydrogenase enzymes and also for the measurement of enzymatic activity.