High-performance liquid chromatography technique for resolving multiple forms of hepatic membrane-bound cytochrome P-450.

Solubilized hepatic microsomal cytochrome P-450 from rats was resolved into 12-different heme-containing components by ion-exchange high-performance liquid chromatography. Separation was accomplished by the utilization of Anpac ion-exchange resin. Phenobarbital (PB) and 3-methylcholanthrene (3-MC) treatment of rats resulted in selective increases or decreases of specific components observed in the elution profile of solubilized microsomes prepared from untreated rats. Treatment with polychlorinated biphenyls increased peaks that were selectively increased by PB or 3-MC treatment. Proteins collected from the major peaks induced by PB or 3-MC treatment were found to retain spectral characteristics of cytochrome P-450. The recovered cytochrome b5 and NADPH-cytochrome c reductase retained spectral properties and enzymic activity, respectively. Purified P-450b obtained from PB-treated rats was found to cochromatograph with one of the peaks selectively induced by PB treatment. These results suggested that it is possible to separate membrane-bound proteins without dramatically altering their physical properties.