[Phosphorylation of aminoacyl-tRNA synthetase preparations of rat liver tissues in vivo and in vitro]

Abstract

The capacity for phosphorylation was studied in aminoacyl-tRNA synthetases isolated from the rat liver after introducing Na2H32PO4 to the organism as well as in the in vitro experiments. Some kinetic characteristics of this reaction were investigated. The velocity of the aminoacyl-tRNA synthetases phosphorylation reaches its maximum 5 minutes later, and the enzyme saturation with substrate occurs at low concentration of the latter. The values of Km, Vmax and V0 are 1.27 x 10(-2) mg/ml, 8.33 mumol 32P/mg per 1 min and 6.09 mumol 32P/mg per 1 min, respectively. A conclusion is drawn that in the in vivo and in vitro experiments there occurs phosphorylation of the total preparation of aminoacyl-tRNA synthetases and individual lysyl-tRNA synthetase.