[Methylation of liver tissue amino acyl-tRNA-synthetases under different experimental conditions]

Incorporation of 14CH3-methionine into the total preparations of aminoacyl-tRNA-synthetases (ARSases) of the rat liver was studied under conditions of X-irradiation as well as with administration of neostigmine methylsulphate and nicotinic acid to the normal and irradiated animals. 3 h after irradiation of animals with a dose of 800 R specific radioactivity of the enzymic preparation increases on the average by 70%, and irradiation against a background of neostigmine methylsulphate administration causes its decrease on the average by 65% as compared to the norm. Thin-layer chromatography on silicagel showed the presence of such methyllated amino acids as lysine, histidine and arginine in acidic hydrolyzate of ARSase total preparations under all the studied experimental conditions.