Kinetics of thermoinactivation of lysil- tRNA - synthetase from liver of X-irradiated rats

A study was made of the kinetics of thermoinactivation of lysil-tRNA-synthetase isolated from rat liver at early times of radiation damage development after the effect of a minimum absolutely lethal X-radiation dose (0.21 C/kg). The thermostability of a dimer form of the enzyme was shown to be higher than that of a monomere. It was established that substrates had a stabilizing effect on the enzyme during thermoinactivation. On the basis of the data obtained from the studies in the kinetic properties of the enzyme and the thermoinactivation a conclusion is made that lysil-tRNA-synthetase is stabilized during subunit aggregation. The thermostability of the enzyme was decreased by irradiation