Hydrogen peroxide-supported activities of semisynthetic flavocytochrome 2B4

摘要

Semisynthetic flavocytochromes, obtained by covalent binding of riboflavin with cytochromes P450 2B4, were able to catalyze the H_2O_2 -mediated reactions of aniline p-hydroxylation, aminopyrine N-demethylation and p-nitroanizole O-dealkylation. The rates of the flavocytochrome-catalyzed, H_2O_2 -supported reactions far exceeded those of the appropriate NADH-dependent reactions and were comparable with the cytochrome P450 2B4-catalyzed, peroxide-mediated reaction rates. The kinetic parameters (k_(cat), K_m) for the peroxide-dependent flavocytochrome P450 2B4 reactions were obtained. Sodium cyanide and SKF-525A, a specific P450 inhibitor, were both shown to inhibit these reactions. The generation of active oxygen species by flavocytochrome 2B4 was registered by chemiluminescence intensity.