[Thymidine phosphorylation with the participation of rat thymic and hepatic thymidine kinase in the presence of a factor from Cl. perfringens (welchii)]. / Fosforilirovanie timidina s uchastiem timidinkinazy iz zobnoi zhelezy i pecheni krys v prisutstvii faktora iz Cl. perfringens (welchii).

Factor CPW, isolated from Cl. perfringens/welchii was shown to activate latent thymidine kinase (factor N) from liver tissue of rats beginning from 42 days age. CPW factor activated 3.5-fold also thymidine kinase from rat strumous gland; the enzyme was observed during involution of the tissue. The data suggest that increase in thymidine kinase activity in proliferating tissues is related to activation of latent enzymes.

[Purification and some properties of the thymidine kinase from the rat thymus]. / Ochistka i nekotorye svoistva timidinkinazy iz zobnoi zhelezy krys

Preparation of thymidine kinase, purified 500-fold, was isolated from rat thymus by means of fractionation with ammonium sulphate, gel filtration on Sephadex G-200, treatment with calcium phosphate gel and chromatography on DEAE-cellulose. The enzyme was shown to be stabilized by 0.12 mM of thymidine, activated by Mg2 (optimum concentration 12 mM) and inhibited by Mn2+ATP served as donor of phosphate groups in reactions, catalyzed by thymidine kinase. In respect to the phosphate acceptor the enzyme showed sharp specificity: it used as a substrate only thymidine, deoxyuridine and its derivatives, substituted at the 5-th position by haloid group. In study of affinity of the enzyme for the substrate Km equals 2.5-10 minus 5 M (Vmax equals 0.09) was determined.