title: In vitro synthesis and processing of a precursor to ornithine aminotransferase.
abstract: Poly(A)+ RNA was isolated from liver-free polysomes of rats maintained on a 60% casein diet by sodium dodecyl sulfate-phenol-chloroform extraction and oligo(dT)-cellulose chromatography. Poly(A)+ RNA translated in a rabbit reticulocyte lysate system produced a polypeptide of 49,000 daltons that was immunoprecipitated by monospecific, affinity-purified IgG antibodies to ornithine aminotransferase (ornithine-oxo acid aminotransferase, EC 2.6.1.13). This polypeptide is 6,000 daltons larger than mature ornithine aminotransferase when electrophoresed on sodium dodecyl sulfate polyacrylamide gels. One-dimensional peptide mapping demonstrated that this 49,000-dalton polypeptide is structurally related to ornithine aminotransferase. Furthermore, it can be processed to a polypeptide of 43,000 daltons by a rat liver mitochondrial fraction. We have concluded that this polypeptide is a precursor to ornithine aminotransferase.
mesh_terms: D000818:Animals; D004792:Enzyme Precursors / Q000235:genetics*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology; D008970:Molecular Weight; D009953:Ornithine-Oxo-Acid Transaminase / Q000096:biosynthesis / Q000235:genetics*; D011061:Poly A / Q000235:genetics; D011132:Polyribosomes / Q000201:enzymology*; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger; D051381:Rats; D011919:Rats, Inbred Strains; D000637:Transaminases / Q000235:genetics*; D005719:gamma-Globulins
chemical_list: D004792:Enzyme Precursors; D012333:RNA, Messenger; D005719:gamma-Globulins; D011061:Poly A; D012313:RNA; D000637:Transaminases; D009953:Ornithine-Oxo-Acid Transaminase