[The effect of ionizing radiation and physical loading on the molecular heterogeneity of nucleoside phosphate kinases in liver subcellular fractions]. / Vliianie ioniziruiushchei radiatsii i fizicheskoi nagruzki na molekuliarnuiu geterogennost' nukleozidfosfatkinaz v subkletochnykh fraktsiiakh pecheni.

The different molecular forms of nucleoside-monophosphate kinases (KF 2.7.4.4) and nucleoside-diphosphate kinases (KF 1.7.4.6) which are responsible for the final steps of pyrimidine nucleotide synthesis were determined in mitochondrial rat hepatic supernatant under condition of combined influence of X-ray and maximum physical exercises (running up to complete exhaustion). The maximum activity of investigated nucleosidediphosphate kinases were observed in intact animals in that fractions which were eluted with tris-HCl buffer solution (0.075 and 1.0 M, pH 7.4). X-ray radiation and physical exercises caused the deviation of chromatographic data of maximal enzymatic activities. The drastic lowering of investigated enzymes was observed after X-ray irradiation and maximum physical exhaustion. This fact is in favour for the suppression of the final steps of primidine nucleotides synthesis under explored conditions of experimental investigations.

[Nucleoside mono- and nucleoside diphosphate kinase activities in rat liver and brain in radiation sickness]. / Nukleozidmono- i nukleoziddifosfatkinaznaia aktivnost' pecheni i golovnogo mozga krys pri luchevoi bolezni.

Activity of nucleoside di- and nucleoside triphosphates metabolism enzymes in tissues of rats gamma-irradiated by a dose of 30 Gy was studied 0.5, 1, 3, 6 and 24 hours after the radiation effect. It is shown that the nucleoside monophosphate kinase activity of the liver and brain is enhanced almost at all stages of the studies and the nucleoside diphosphate kinase activity is inhibited. A significant but reversible decrease of the nucleoside monophosphate kinase activity is observed in the liver 3 h later. By an end of the first day after irradiation the nucleoside mono- and nucleoside diphosphate kinase activities increase significantly both in the liver and brain.