[Creatine kinase of rat lymphocytes and its activity as affected by adenosine, cAMP, AMP and products of their transformation].

Creatine kinase is found in the thymus and spleen lymphocytes of rats. Its activity in the spleen lymphocytes is considerably higher than in the thymocytes. The data of enzyme-electrophoresis chromatography on DEAE-Sephadex A-50, thermostability and pH optimum indicate that lymphocyte creatine kinase is a "cerebral" isoenzyme. It is mainly concentrated in hyaloplasm and mitochondrial fraction and, to a less extent--in the microsomal and nuclear-cellular fractions. It is shown that adenosine, inosine, hypoxanthin, NH4, cAMP and GTP have no effect on the creatine kinase activity of thymocytes but pyrophosphate causes its decrease. Creatine kinase of lymphocytes as compared with its myocardium isoenzyme MM possesses a less substrate specificity to nucleotide diphosphates.