Pyrimidine biosynthesis in Neisseria meningitidis. 1. Demonstration of enzyme activities.

Activities of the five enzymes specific for the pyrimidine biosynthetic pathway, aspartate carbamoyl-transferase (ACTase), dihydroorotase (DHOase), dihydroorotate dehydrogenase (DHOdehase), orotate phosphoribosyltransferase (OMPppase), and orotidine 5'-phosphate decarboxylase (OMPdecase) were found in cell-free extracts of Neisseria meningitidis. Extracts also contained enzyme activities corresponding to the arginine pathway enzyme ornithine carbamoyltransferase (OCTase), and to carbamoylphosphate synthetase (CPSase), the enzyme common to both pathways. N. meningitidis possessed a single glutamine-dependent CPSase.