Utilization of thymine, thymidine and TMP by Neisseria meningitidis. 2. Lack of enzymes for specific incorporation of exogenous thymine, thymidine and TMP into DNA.

Abstract

Activities corresponding to thymidine phosphorylase and nucleoside deoxyribosyl transferase could not be found in Neisseria meningitidis. 14C‐2‐thymine was bound to or taken up by whole cells, but this did not result in labelling of the TMP, TDP or TTP pools. No significant thymidine kinase activity could be induced in N. meningitidis. 14C‐2‐thymidine which was bound to or taken up by whole cells resulted in faint labelling of the TMP, TDP and TTP pools after prolonged incubation, but no radioactive thymine appeared. The N. meningitidis extracts had activities corresponding to TMP and TDP kinases, but whole cells which were exposed to TMP‐methyl‐3H did not seem to take up significant amounts of this compound. The findings indicate that N. meningitidis lacks the enzyme systems that are known to mediate a specific incorporation of thymine or thymidine into DNA.