[Electrochemical reduction of cytochrome P450s based on electrodes with immobilized substrates].

A new approach for the electrochemical reduction of cytochromes P450 (P450s, CYPs) with electrodes chemically modified with appropriate substrates of P450s ("reverse" electrodes) has been proposed. The method is based on the analysis of cyclic voltammograms, square wave voltammograms, amperograms and determination of such electrochemical characteristics as catalytic current and redox potential. The sensitivity of the proposed method is 0.2-1 nmol P450/electrode. The differences of maximal current and potentials in square wave voltammograms and catalytic current in amperometric measurements are more sensitive and reliable. Planar regime of screen-printed electrodes permits to use 20-60 microl of electrolyte volume. We investigated P450 2B4--benzphetamine or P450scc--cholesterol enzyme - substrate pairs. Electrochemical parameters of electrodes with nonspecific P450 substrate were differed from electrodes with appropriate substrates.