NUCLEOSIDE KINASES OF MARINE-BACTERIA - OCCURRENCE AND PROPERTIES

Cell extracts of 26 strains from the Collection of Marine Microorganis ms of the Pacific Ocean Institute of Bioorganic Chemistry were assayed for the presence of thymidine and uridine kinases. Thymidine kinase a ctivity was revealed in all 26 of the strains tested, and uridine kina se activity was found in 22 strains. Cells with sufficiently high kina se activity rapidly consumed the respective labeled nucleoside in vivo ; thymidine was incorporated into DNA, and uridine, into both DNA and RNA. Ion-exchange chromatography of cell extracts showed that each of the three strains studied in this respect contained several enzymes ca pable of phosphorylating thymidine, uridine, and thymidine monophospha te. Purified nucleoside kinases were examined for their ability to use various nucleosides as phosphate accepters. It was found that all the nucleoside kinases examined had broad substrate specificity.