[Activation of L-amino acids by aminoacyl-tRNA-synthetases from yeast Candida utilis IBPM-405].

The procedure for isolating aminoacyl-tRNA-synthetases from yeast Candida utilis IBPM-405 was developed. The rate of activation of L-amino acids in the formation of hydroxamates was different. Aspartic acid, asparagine, glutamic acid, tryptophane, phenyl alanine and methionine underwent the highest activation. The activation of alanine, arginine, hydroxyproline, serine and isoleucine was insignificant. Using aspartic acid, it was shown that the hydroxamate formation was ATP-stimulated and that the amount of hydroxamate increased with a rise of the protein concentration in the mixture to 9-10 mg/ml. The hydroxamate formation was inhibited by p-chloromercury-benzoate and heavy metal ions. Yeast aminoacyl-tRNA-synthetases showed L-aspartic and L-glutamic activities that were independent from Mg++ ions and ATP.