title: Partial purification and properties of rat liver mitochondrial polynucleotide phosphorylase.
abstract: 1. Polynucleotide phosphorylase was partially purified from the inner membrane of rat liver mitochondria. 2. The partially purified particulate enzyme catalyses phosphorolysis of poly(A), poly(C), poly(U) and RNA to nucleoside diphosphates. 3. It is devoid of nucleoside diphosphate-polymerization activity. 4. Variable amounts of ADP/P(i)-exchange activity are associated with the polynucleotide phosphorylase and are probably due to a different enzyme. 5. ADP is the preferred substrate for exchange, and little or no reaction occurs with other nucleoside diphosphates, but ATP/P(i)-exchange takes place at one-third the rate observed with ADP. 6. The partially purified enzyme is free from the phosphatases found in the crude mitochondrial inner membrane, but is associated with an endonuclease activity and some adenylate kinase activity; no cytidylate kinase activity analogous to the latter was detectable.
mesh_terms: D000244:Adenosine Diphosphate; D000818:Animals; D002458:Cell Fractionation; D002498:Centrifugation; D002854:Chromatography, Paper; D008345:Manganese; D008566:Membranes / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology*; D010710:Phosphates; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis; D011119:Polynucleotides; D011117:Polyribonucleotide Nucleotidyltransferase / Q000302:isolation & purification; D011755:Pyrophosphatases / Q000032:analysis; D012316:RNA Nucleotidyltransferases / Q000302:isolation & purification*; D051381:Rats; D012965:Sodium Chloride
chemical_list: D010710:Phosphates; D011119:Polynucleotides; D008345:Manganese; D012965:Sodium Chloride; D000244:Adenosine Diphosphate; D012316:RNA Nucleotidyltransferases; D011117:Polyribonucleotide Nucleotidyltransferase; D010744:Phosphoric Monoester Hydrolases; D011755:Pyrophosphatases