title: An in vivo effect of the metabolites L-alanine and glycyl-L-leucine on the properties of the lysyl-tRNA synthetase from Escherichia coli K-12. II. Kinetic evidence.
abstract: Wild-type Escherichia coli K-12 was grown in minimal medium alone or with the addition of 20 mM L-alanine or 3 mM glycyl-L-leucine. A lysyl-tRNA synthetase mutant strain was grown in minimal medium containing 20mM L-alanine. The lysyl-tRNA synthetase from these strains was purified to 70-90% of homogeneity. Kinetic studies comparing the effect of thermal and urea inactivation on these different lysyl-tRNA synthetase preparations and measurement of the Michaelis constant for lysine and transfer RNA indicated that growth of Escherichia coli in the presence of alanine and glycyl-L-leucine induces an alteration in the properties of the synthetase. Measurement of the apparent Km for ATP at pH 7.25 indicates lysyl-tRNA synthetase has two two binding sites for this substrate, and further studies indicated a dependence of the apparent Km for lysine on the ATP concentration.
mesh_terms: D000409:Alanine / Q000494:pharmacology*; D000604:Amino Acyl-tRNA Synthetases / Q000494:pharmacology*; D001665:Binding Sites; D004151:Dipeptides / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology*; D005998:Glycine; D006358:Hot Temperature; D007700:Kinetics; D007930:Leucine; D008250:Lysine-tRNA Ligase / Q000494:pharmacology*; D009154:Mutation; D009994:Osmolar Concentration; D011489:Protein Denaturation; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D014508:Urea
chemical_list: D004151:Dipeptides; D012965:Sodium Chloride; D014508:Urea; D000604:Amino Acyl-tRNA Synthetases; D008250:Lysine-tRNA Ligase; D007930:Leucine; D000409:Alanine; D005998:Glycine