RESUMEN
The electrochemical reduction of the recombinant form of human cytochrome P450 17A1 (CYP17A1) was investigated. Hemeprotein was immobilized on electrode modified with biocompatable nanocomposite material based on the membrane-like synthetic surfactant didodecyldimethylammonium bromide (DDAB) and gold nanoparticles. Analytical characteristics of DDAB/Au/CYP17A1 electrodes were investigated with cyclic voltammetry, square wave voltammetry, and differential pulse voltammetry. Analysis of electrochemical behaviour of cytochrome P450 17A1 was conducted in the presence of substrate pregnenolone (1), inhibitor ketoconazole (2), and in the presence of synthetic derivatives of pregnenolone: acetylpregnenolone (3), cyclopregnenolone (4), and tetrabrompregnenolone (5). Ketoconazole, azole inhibitor of cytochromes P450, blocked catalytic current in the presence of substrate pregnenolone (1). Compounds 3-5 did not demonstrate substrate properties towards electrode/CYP17A1 system. Compound 3 did not block catalytic activity towards pregnenolone, but compounds 4 and 5 inhibited such activity. Electrochemical reduction of CYP17A1 may serve as an adequate substitution of the reconstituted system which requires additional redox partners - for the exhibition of catalytic activity of hemoproteins of the cytochrome P450 superfamily.