Aryl-alcohol oxidase (AAO) electrochemistry studies, using graphite-modified electrodes, are presented for the first time herein. The increase in current upon injection of the analyzed substrate was shown to be approximated by Michaelis-Menten type dependence. The calculated kinetic constants were used to characterize the native (non-mutated) recombinant AAO expressed in Escherichia coli, as well as the native enzyme and the F501Y and F501A variants expressed in Emericella nidulans. Results from cyclic voltammetry experiments conducted with the enzymes adsorbed on graphite electrodes or with the enzymes in solution (using glassy carbon electrode as working electrode) gave information on the redox potential of these enzymes. (c) 2008 Elsevier B.V. All rights reserved.