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

Eur J Biochem. 1976 Jul 15;66(3):493-7. doi: 10.1111/j.1432-1033.1976.tb10574.x.

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

  • Adenosine Triphosphate / analogs & derivatives*
  • Amino Acyl-tRNA Synthetases / metabolism*
  • Binding, Competitive
  • Catalysis
  • Chemical Phenomena
  • Chemistry
  • Isoleucine-tRNA Ligase / antagonists & inhibitors
  • Isoleucine-tRNA Ligase / metabolism*
  • Kinetics
  • Saccharomyces cerevisiae / enzymology*
  • Structure-Activity Relationship
  • Transfer RNA Aminoacylation
  • Tyrosine-tRNA Ligase / antagonists & inhibitors
  • Tyrosine-tRNA Ligase / metabolism*
  • Valine-tRNA Ligase / antagonists & inhibitors
  • Valine-tRNA Ligase / metabolism*

Substances

  • Adenosine Triphosphate
  • Amino Acyl-tRNA Synthetases
  • Tyrosine-tRNA Ligase
  • Isoleucine-tRNA Ligase
  • Valine-tRNA Ligase