Molecular Pharmacology, Vol 7, 500-510, Copyright © 1971 by the American Society for Pharmacology and Experimental Therapeutics

Chromatography of Radioactive Microsomal Hemoproteins on Diethylaminoethyl Cellulose

¹ The Wellcome Research Laboratories, Burroughs Wellcome & Company, U. S. A., Inc., Tuckahoe, New York 10707

Administration of ¹⁴C- or 3H--aminolevulinic acid to immature male rats resulted in the incorporation of radioactivity into liver microsomal hemoprotein. Column chromatography of "solubilized" microsomes or CO-binding particles⁴ obtained from rats treated with phenobarbital or 3-methylcholanthrene revealed that essentially all the radioactivity was associated with fractions containing cytochromes b₅, P-450, P-448, and P-420. The results indicated that radioactivity incorporated into microsomes and CO-binding particles after administration of ¹⁴C- or ³H--aminolevulinic acid is associated almost exclusively with cytochromes, and that very little, if any, nonspecific binding of heme occurs.

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ACKNOWLEDGMENT The authors wish to thank Mrs. P. Althoff for typing the manuscript.