Increase of thymidine, thymidylate and deoxycytidine kinase activities during germination of bacterial spores

Abstract

1. 1. Very low activities of thymidine kinase (ATP: thymidine 5′-phosphotransferase, EC 2.7.1.21), thymidylate kinase (ATP: 5′-thymidylic acid phosphotransferase) and deoxycytidine kinase (ATP: deoxycytidine 5′-phosphotransferase) were found in crude extracts from bacterial spores as compared with those from vegetative cells. This was repeatedly confirmed by applying various extraction methods. 2. 2. Activities of thymidine kinase and deoxycytidine kinase increased during germination of spores simultaneously with the initiation of DNA synthesis, but the increase of thymidylate kinase activity was delayed. 3. 3. The correlation between the increase of kinase activities and the rate of DNA synthesis was seen in spores germinated in starved as well as in complete conditions. This correlation, however, was not held in germination of heavily irradiated spores, suggesting that the formation of the kinases is under different control from that for DNA polymerization in cells. 4. 4. The increase in the kinase activities was inhibited by 100 μg/ml of chloramphenicol, indicating de novo formation of the kinases. By delayed addition of chloramphenicol the kinases were distinguished from early proteins synthesized during the first 30–80 min of germination. 5. 5. The possibilities that an inhibitor of thymidine kinase is present in spores and that a thymidine kinase activator is present in vegetative cells were eliminated.