Metabolism of purine nucleosides in human and ovine lymphocytes and rat thymocytes and their influence on mitogenic stimulation.

摘要: Abstract 1. Phosphorolysis and phosphorylation rates of inosine, guanosine, deoxyguanosine were determined in disrupted intact human ovine lymphocytes rat thymocytes related with their effect on mitogenic stimulation. 2. Activity purine nucleoside phosphorylase (EC 2.4.2.1) was about 10 times higher extracts than those lymphocytes. Apparent K m values for inosine guanosine lymophocytes (about 100 μM) (50 μM). μM the all three cell types. 3. In presence kinase activity established. Deoxyguanosine detected 4. The rate much lower phosphorolysis both cells. 5. Deoxyguanosine, incorporated by cells into nucleotides nucleic acids. This incorporation only partially due to subsequent conversion hypoxanthine-guanine phosphoribosyltransferase 2.4.2.8). appeared be completely this route. 6. Inosine (0.5 mM) did not inhibit thymidine phytohemagglutinin-stimulated At same concentration deoxyinosine caused 50% inhibition, but inhibited almost completely. Thymidine concanavalin A-stimulated hardly 0.5 mM 50 25% complete respectively.