The role of components of the endoplasmic reticulum in the biosynthesis of cytochrome P-450.
1. Antibodies have been prepared to rat hepatic cytochrome P-450 and their specificity demonstrated. These antibodies have been used to investigate the biosynthesis of cytochrome P-450 in vitro and in situ in various components of the endoplasmic reticulum. 2. A preparation of heavy rough endoplasmic reticulum translocates proteins newly biosynthesized in vitro vectorially into the luminal space and these are released by low concentrations of deoxycholate. A significant proportion of the radioactivity found in this released fraction is incorporated into cytochrome P-450. 3. Following incorporation of [14C]leucine by perfused rat liver, radioactively labelled cytochrome P-450 can be found in the intrascisternal content of heavy rough, light rough and smooth endopalsmic reticulum and also in a solublized Golgi preparation. 4. We suggest that at least part of the newly biosynthesized cytochrome P-450 is translocated into the intracisternal space of the rough endoplasmic and then passes through the other components of the endoplasmic reticulum before insertion at its ultimate membrane locus.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000302:isolation & purification; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005779:Immunodiffusion; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D008970:Molecular Weight; D010634:Phenobarbital / Q000494:pharmacology; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D051381:Rats
D003577:Cytochrome P-450 Enzyme System; D010634:Phenobarbital