Purine metabolism in Neisseria meningitidis. 3. Utilization of exogenous hypoxanthine, guanine and xanthine.

Whole cells of Neisseria meningitidis have been found to utilize exogenous radioactive hypoxanthine, guanine and xanthine. When hypoxanthine was the precursor, the pools of both the adenine and the guanine 5'-ribonucleotides were labelled. Guanine and xanthine were utilized with labelling of the pool of the guanine 5'-ribonucleotides only. Crude extracts from N. meningitidis were found to have activities corresponding to hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) and another phosphoribosyltransferase which seems to exhibit specificity for guanine and xanthine. Crude extracts phosphorylated guanosine 5'-monophosphate to guanosine 5'-triphosphate in the presence of adenosine 5'-triphosphate (ATP) and MgCl2.