title: Myocardial aminoacyl-transfer-ribonucleic acid synthetase and aminoacyl-transferring enzyme activity.
abstract: The properties of cytoplasmic aminoacyl-tRNA synthetase and aminoacyl-transferring enzymes in the myocardium were examined and methods for the assay of the activity of these enzyme systems were developed. Aminoacyl-tRNA synthetase activity was measured from the rate of incorporation of (14)C-labelled amino acid into aminoacyl-tRNA. Transferase activity was measured from the rate of incorporation of amino[(14)C]acyl-tRNA into protein in the presence of a standard preparation of hepatic ribosomes. Aminoacyl-tRNA synthetase activity is labile once the heart has been homogenized, whereas transferase activity is stable. The source of energy for synthetase activity is ATP; that for transferase is GTP. Transferase activity was inhibited by puromycin and stimulated by dithiothreitol, whereas synthetase activity was unaffected.
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000596:Amino Acids / Q000378:metabolism; D000604:Amino Acyl-tRNA Synthetases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002247:Carbon Isotopes; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology; D004229:Dithiothreitol / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D007930:Leucine / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D010455:Peptides; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism; D011691:Puromycin / Q000494:pharmacology; D012343:RNA, Transfer; D011817:Rabbits; D051381:Rats; D012270:Ribosomes / Q000378:metabolism; D014166:Transferases / Q000037:antagonists & inhibitors; D014633:Valine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D010455:Peptides; D011506:Proteins; D010649:Phenylalanine; D011691:Puromycin; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D012343:RNA, Transfer; D014166:Transferases; D000217:Acyltransferases; D000604:Amino Acyl-tRNA Synthetases; D007930:Leucine; D014633:Valine; D004229:Dithiothreitol