Stoichiometry of electrocatalytic cycle of cytochrome P450 2B4

摘要

Stoichiometry of the electrocatalytical cycle of cytochrome P450 2134 was studied in kinetic mode according to bielectrode scheme. Graphite screen-printed electrodes with immobilized cytochrome P450 2134 were used as the operating electrode (at the potential E-0'= -450 mV) and electrodes, modified with cytochrome c (E-0'= -50 mV) or Prussian Blue (E0(') = 0), as measuring electrodes (for H2O2) and Clark-type electrode (for 02). Benzphetamine N-demethylation rate was 17 +/- 3 nmolmol of enzyme/min, peroxide production was 4.8 +/- 0.7 nmolmol of enzyme/min (substrate-free system), 3.3 +/- 0.6 nmolmol of enzyme/min (0.5 mM benzphetamine), the oxygen consumption rate by P450 2134 was 19.4 +/- 0.6 nmolmol of enzyme/min (in the presence of benzphetamine), 4.8 +/- 0.4 nmolmol of enzyme/min (without substrate). Based on stoichiometry of P450 electrocatalysis adequacy of electrochemical reduction and P450-monooxygenase system was revealed. (C) 2008 Published by Elsevier Inc.