Proteolytic processing of the primary translation product of rat intestinal apolipoprotein A-IV mRNA. Comparison with preproapolipoprotein A-I processing.
Total cellular RNA, isolated from rat intestinal epithelium, was translated in a wheat germ cell-free system, and the primary translation product of apolipoprotein A-IV mRNA was purified by immunoprecipitation with monospecific antibody. NH2-terminal sequence analyses of mature rat plasma high density lipoprotein-associated A-IV and the cell-free product revealed that A-IV is initially synthesized with a 20-amino-acid NH2-terminal extension. Co-translational cleavage of the primary translation product indicated that the entire NH2-terminal extension behaved as a prepeptide. The prepeptides of intestinal apolipoproteins A-I and A-IV have 59% sequence homology. However, A-IV does not possess the unusual propeptide previously identified in intestinal A-I (Gordon, J. I., Smith, D. P. Andy, R., Alpers, D. H. Schonfeld, G., and Strauss, A. (1982) J. Biol. Chem. 257, 971-978). Therefore it appears that proteolytic processing of these two apolipoproteins differs significantly.
D000595:Amino Acid Sequence; D000818:Animals; D001053:Apolipoproteins / Q000235:genetics*; D001054:Apolipoproteins A; D007421:Intestine, Small / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000235:genetics; D008297:Male; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains
D001053:Apolipoproteins; D001054:Apolipoproteins A; D008075:Lipoproteins, HDL; D011498:Protein Precursors; D012333:RNA, Messenger; C022205:apolipoprotein A-IV; C035250:preproapolipoprotein A-I