title: Localization of nascent NADPH-cytochrome c reductase in rat liver microsomes.
abstract: Rat liver microsomes incubated with [3H] puromycin in high salt buffer were digested with a mixture of protease, trypsin and chymotrypsin, in both the presence and absence of 1 % deoxycholate. Our observations revealed that the proteolysis of peptidyl puromycin labeled with [3H] puromycin was at least partially protected by the presence of microsomal membrane. Immuno-chemical analyses have further shown that most of the nascent NADPH-cytochrome c reductase in the microsomes was digested with the proteases while serum albumin was effectively protected from the digestion. It is thus proposed that NADPH-cytochrome c reductase synthesized on the membrane bound ribosomes is not transported to the vesicular cavity but directly to the outer surface of the microsomal membrane in a form which is accessible to the proteases.
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D000818:Animals; D002918:Chymotrypsin; D003579:Cytochrome Reductases / Q000096:biosynthesis* / Q000276:immunology; D003840:Deoxycholic Acid / Q000494:pharmacology; D007700:Kinetics; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D011233:Precipitin Tests; D011691:Puromycin / Q000378:metabolism; D051381:Rats; D014357:Trypsin
chemical_list: D003840:Deoxycholic Acid; D011691:Puromycin; D003579:Cytochrome Reductases; D000217:Acyltransferases; D002918:Chymotrypsin; D014357:Trypsin