[Peroxide-dependent oxidation of substrates of polysynthetic flavocytochrome 2B4]

Semisynthetic flavocytochromes, obtained by covalent binding of riboflavins with cytochrome P450 2B4, were able to catalyse H2O2-supported aniline p-hydroxylation, amidopyrine N-demethylation and p-nitroanisole O-dealkylation. Rates of these reactions were considerably higher than the rates of corresponding NAD(P)H-dependent reactions and comparable with H2O2-dependent reactions, catalysed by cytochrome P450. Kinetic parameters (Km and kcat) of hydrogen peroxide-supported oxidation of aniline, amidopyrine and p-nitroanisole in the presence of flavocytochrome 2B4 were determined. Cyanide and SKF-525 A inhibited H2O2-dependent reactions of flavocytochrome 2B4. The intensity of luminol chemiluminescence in the presence of hydrogen peroxide was studied. Chemiluminescent response was shown to be influenced by cyanide ions and SKF 525 A. The difference in chemiluminescence intensity of cytochrome P450 2B4 and semisynthetic flavocytochrome 2B4 was found.