Kinetics of elementary steps in the cytochrome P-450 reaction sequence. III. NADPH reduction of cytochrome P-450LM at different integrational levels.
Acta Biol Med Ger, 1979;38(1):11-21.
Blanck J, Behlke J, Jänig GR, Pfeil D, Ruckpaul K
PMID: 42245
Abstract
The aerobic NADPH reduction of cytochrome P-450LM has been investigated on microsomes, as well as on the solubilized enzyme system in the associated, disintegrated, and reconstituted state, respectively. P-450 exhibits biphasic reduction kinetics of about 70/30% phase distribution and rate constants differing 10-fold. The partial reactions are due to organizational asymmetries, the cytochrome being either incorporated into P-450/reductase associates (cluster) or localized outside (randomly distributed, homoassociated, weakly cluster-associated). Triton N-101 disintegrates the different associate structures, consequently followed by the disappearance of the rapid reaction phase. The enzyme system can be reconstituted; at microsomal stoichiometry the respective standard parameters are approached, depending on the composition and structural organization of the phospholipid. The reorganization without any membrane matrix is obviously thermodynamically determined.
MeSH terms
Animals; Benzphetamine; Cytochrome P-450 Enzyme System; Kinetics; Microsomes, Liver; NADP; Oxidation-Reduction; Oxidoreductases, N-Demethylating; Polyethylene Glycols; Rabbits; Solubility
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