title: Processing of rat liver apoprotein E primary translation product.
abstract: The primary translation product of rat liver apoE mRNA was isolated from wheat germ cell-free translation systems. Plasma apoE and the primary translation product migrated similarly on SDS-polyacrylamide gels, had similar partial proteolytic peptide maps, and bound to and coeluted from heparin-Sepharose columns. Comparison of the partial amino acid sequence of the primary translation product with the amino-terminal sequence of plasma apoE indicated that rat apoE is initially synthesized with an 18 amino acid amino-terminal extension. This entire segment was removed cotranslationally by canine microsomes possessing signal peptidase activity. The microsome-processed translation product did not contain an endoglycosidase H-sensitive oligosaccharide, suggesting that rat apoE is O-glycosylated.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001053:Apolipoproteins / Q000097:blood / Q000235:genetics*; D001057:Apolipoproteins E; D002474:Cell-Free System; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006493:Heparin / Q000378:metabolism; D008099:Liver / Q000032:analysis*; D008297:Male; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008861:Microsomes / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014908:Triticum
chemical_list: D001053:Apolipoproteins; D001057:Apolipoproteins E; D010455:Peptides; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D006493:Heparin; D006026:Glycoside Hydrolases; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase