Molecular Pharmacology, Vol 12, 921-932, Copyright © 1976 by the American Society for Pharmacology and Experimental Therapeutics

Studies of the Metabolism of Diethyl p-Nitrophenyl Phosphorothionate (Parathion) and Benzphetamine Using an Apparently Homogeneous Preparation of Rat Liver Cytochrome P-450: Effect of a Cytochrome P-450 Antibody Preparation

¹ Center in Environmental Toxicology, Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232

A procedure is described for simultaneous purification of cytochrome P-450 and partial purification of NADPH-cytochrome c reductase from the livers of phenobarbital-treated rats. Using a reconstituted system containing these enzymes, we have examined the metabolism of benzphetamine and parathion. Both dilauroylphosphatidylcholine and deoxycholate must be present in the reconstituted system for maximal metabolism of these two substrates. Excluding deoxycholate from an otherwise complete reconstituted system decreases the rate of metabolism of benzphetamine by about 80%, and of parathion by approximately 40%. The maximal rates of metabolism of benzphetamine and parathion using this rat liver reconstituted system resemble those observed using reconstituted systems containing cytochrome P-450 and NADPH-cytochrome c reductase similarly prepared from the livers of phenobarbital-treated rabbits. An antibody (or antibodies) to the rat liver cytochrome P-450 has been prepared by injecting this enzyme into rabbits. Using Ouchterlony double-diffusion analysis, this antiserum exhibits good reactivity against rat liver cytochrome P-450 but poor reactivity with apparently homogeneous cytochrome P-450 purified from the livers of phenobarbital-treated rabbits. In contrast, using quantitative immunoprecipitation, some affinity of the rat liver cytochrome P-450 antibody for rabbit liver cytochrome P-450 can be demonstrated. The antibody preparation also inhibits the ability of a rabbit liver reconstituted system to metabolize parathion. However, in all cases, the antibody preparation is much more active against rat liver cytochrome P-450.

This article has been cited by other articles:

				S.-i. Yamagata, S. Ohmori, N. Suzuki, M. Yoshino, M. Hino, I. Ishii, and M. Kitada Metabolism of dacarbazine by rat liver microsomes contribution of CYP1A enzymes to dacarbazine N-demethylation. Drug Metab. Dispos., April 1, 1998; 26(4): 379 - 382. [Abstract] [Full Text]