title: Valyl-tRNA, isoleucyl-tRNA and tyrosyl-tRNA synthetase from baker's yeast. Substrate specificity with regard to ATP analogs and mechanism of the aminoacylation reaction.
abstract: Nineteen analogs of ATP have been tested in the aminoacylation of valyl-tRNA, isoleucyl tRNA and tyrosyl-tRNA synthetases from baker's yeast. Four compounds are substrates for valyl tRNA and two for isoleucyl-tRNA synthetase, but there is no modified substrate for the tyrosyl tRNA synthetase. There is one inhibitor for valyl-tRNA synthetase, eight compounds inhibit isoleucyl-tRNA synthetase and two compounds inhibit tyrosyl-tRNA synthetase. Their Km and Ki and V values have been determined. The substrate specificity shows that positions 2, 6, 7, 8, 9, 2', and 3' of ATP are important for catalytic action of these aminoacyl-tRNA synthetases.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives*; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001667:Binding, Competitive; D002384:Catalysis; D055598:Chemical Phenomena; D002621:Chemistry; D007533:Isoleucine-tRNA Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013329:Structure-Activity Relationship; D046249:Transfer RNA Aminoacylation; D014448:Tyrosine-tRNA Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014637:Valine-tRNA Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases; D014448:Tyrosine-tRNA Ligase; D007533:Isoleucine-tRNA Ligase; D014637:Valine-tRNA Ligase