Electrocatalytic Oxidation of Dihydronicotinamide Adenine Dinucleotide with Ferrocene Carboxylic Acid by Diaphorase fromClostridium kluveri. Remarks on the Kinetic Approaches Usually Adopted

The kinetics of the electron transfer between NADH and ferrocenecarboxylic acid (FMCA) catalyzed by diaphorase from Clostridium kluveri (EC 1.8.1.4.) was studied by voltammetry. A commercially available digital simulation program permitted one to determine the rate constants of the catalytic system by a fitting procedure. A rate constant of 3×104 M−1 s−1was found for the reaction between diaphorase and mediator while a value of 8 M−1 s−1was found for the parallel competitive reaction between NADH and mediator. In addition a comparison of the present method to other data treatment procedures reported in the literature and a brief evaluation of their limits of applicability were carried out.