Molecular Pharmacology, Vol 13, 50-59, Copyright © 1977 by the American Society for Pharmacology and Experimental Therapeutics

Heme Regulation of Cytochrome Oxidase Synthesis in Fetal Rat Liver

¹ Environmental Toxicology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709

The role of heme in regulation of the synthesis of cytochrome oxidase, a mitochondrial hemoprotein, was studied in fetal rat liver. A functional association between heme levels and the synthesis of cytochrome oxidase in vivo is suggested by the rapid decline in the rate of incorporation of [³H]-aminolevulinic acid and, subsequently, [¹⁴C]leucine into cytochrome oxidase following selective inhibition of heme biosynthesis with CoCl₂. Both the functional activity and the rate of [¹⁴C]leucine incorporation into fetal cytochrome oxidase are stimulated when heme is administered 30 min after CoCl₂ is given. In contrast, heme does not stimulate [¹⁴C]leucine incorporation or enhance the functional activity of cytochrome oxidase following selective inhibition of cytoribosomal protein synthesis with cycloheximide. Thus it is suggested that heme stimulates the synthesis of apocytochrome oxidase de novo and mediates the formation of the functional cytochrome in fetal rat liver.

Note:
ACKNOWLEDGMENTS The author acknowledges the excellent technical assistance of Mrs. Geraldine Carver in the performance of these studies.

This article has been cited by other articles:

				L. Hiser and J. P. Hosler Heme A Is Not Essential for Assembly of the Subunits of Cytochrome c Oxidase of Rhodobacter sphaeroides J. Biol. Chem., November 21, 2001; 276(48): 45403 - 45407. [Abstract] [Full Text] [PDF]