TY - JOUR T1 - Reconstituted liver microsomal enzyme system that hydroxylates drugs, other foreign compounds, and endogenous substrates. IX. The formation of a 455-nm metabolite-cytochrome P-450 complex. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 190 LP - 194 VL - 4 IS - 2 AU - J C Kawalek AU - W Levin AU - D Ryan AU - A Y Lu Y1 - 1976/03/01 UR - http://dmd.aspetjournals.org/content/4/2/190.abstract N2 - The reconstituted liver microsomal hydroxylation system was used to study the formation of a metabolite-cytochrome P-450 complex absorbing maximally at 455 nm, with benzphetamine and N-hydroxyamphetamine as substrates. Complex formation required the presence of NADPH, substrate, NADPH-cytochrome c reductase, lipid, and cytochrome P-450, indicating that metabolism of the substrate is essential. In the presence of fixed amounts of lipid and NADPH-cytochrome c reductase, the rate of complex formation with cytochrome P-450 isolated from phenobarbital-treated rats was much greater than that observed with cytochrome P-48 from 3-methylcholanthrene-treated rats or rabbits. These results are consistent with recent studies indicating that different forms of cytochrome P-450 with distinct spectral, catalytic, and immunological properties exist in liver microsomes. ER -