Effect of lipids and substrates on the kinetics of binding of ferrocytochrome P-450 to CO
Davydov, R.M.; Khanina, O.I.; Iagofarov, S.; Uvarov, V.I.; Archakov, A.I.
Biokhimiia 51(1): 125-129
1986
ISSN/ISBN: 0320-9725 PMID: 3955103 Document Number: 268730
Using the flash photolysis technique, it was found that the kinetics of recombination of carbon monoxide with ferrocytochrome P-450 LM-2 can be approximated by the sum of three exponents. Incorporation of cytochrome P-450 into liposomes prepared from microsomal lipids leads to the reduction of the number of steps to two as well as to essential changes in rate constants. Addition of type I substrates (Triton N-101, albumin) cause similar changes in the reaction kinetics. NADPH-cytochrome P-450 reductase has no effect on this process. The multistep kinetics of CO recombination with cytochrome P-450 LM-2 may be accounted for by the presence of some protein conformers. The experimental results suggest that the activity and structure of cytochrome P-450 conformers is affected by the lipid microenvironment, type I substrates and Triton N-101.