Role of Lysine and Arginine Residues of Cytochrome P450 in the Interaction between Cytochrome P4502B1 and NADPH-Cytochrome P450 Reductase

摘要: Abstract Chemical modification of cytochrome P450 was used to study the involvement lysine and arginine residues in interaction between NADPH-cytochrome reductase. Acetylation 2.2 8.5 mol lysine/mole by acetic anhydride led 38.7 95% reductions, respectively, benzphetamine demethylation activity NADPH-dependent reconstituted P450/reductase complex, while up lysine/mol did not inhibit cumene hydroperoxide-supported P450-dependent demethylation. does grossly disturb protein conformation as revealed absolute, CO-difference fluorescence spectral studies. Modification P4502B1 affect its substrate binding ability either. Lysine putatively involved with reductase have been identified radiolabeling [14C]acetic followed trypsin digestion, HPLC separation, amino acid microsequencing. Radiolabeled lysines occur at positions 251, 384, 422, 433, 473. phenylglyoxal 2,3-butanedione seemed no significant effect on either NADPH or supported hydroperoxide. Studies incorporation [14C]phenylglyoxal showed concentration- time-dependent into P4502B1. These results support hypothesis a predominant role residuesof electrostatic