Abstract: | It is shown from a combination of rapid quenching and steady-state kinetics that the phenylalanyl-tRNA synthetase from yeast catalyses the formation of phenylalanyl-tRNA by the amino-acyladenylate pathway at pH 7.8 and 25 degrees C. The rate-determining step at saturating reagent concentrations is not the dissociation of the charged tRNA from the enzyme. |