Direct electron transfer of redox proteins on a Nafion-cysteine modified gold electrode

A novel Nafion-cysteine functional membrane was constructed. Rapid and direct electron transfer of horseradish peroxidase, Euphorbia latex amine oxidase, superoxide dismutase and cytochrome c was carried out on the functional membrane modified gold electrode with good stability and repeatability. The immobilized protein modified electrodes showed quasi-reversible electrochemical redox behaviors with formal potentials of 60, 35, 66 and 38 mV (vs. Ag/AgCl) in 20 mM potassium phosphate buffer solution, pH 7.0 at 25 degrees C. The cathodic transfer coefficients were 0.42, 0.42, 0.45, 0.44 and electron transfer rate constants were evaluated to be 1.2, 1.6, 1.0 and 0.6 s(-1). (c) 2006 Elsevier B.V. All rights reserved.