The pyrimidine biosynthetic pathway and its regulation in Pseudomonas jessenii.

The control of the pyrimidine biosynthetic pathway by pyrimidine bases was examined in Pseudomonas jessenii ATCC 700870. The pyrimidine biosynthetic enzymes aspartate transcarbamoylase, dihydroorotase, dihydroorotate dehydrogenase, orotate phosphoribosyltransferase, and orotidine 5'-monophosphate (OMP) decarboxylase activities were found to be higher in the succinate-grown ATCC 700870 cells than the glucose-grown cells. All the enzyme activities were depressed in uracil-supplemented ATCC 700870 glucose-grown cells relative to the unsupplemented cells which was indicative of possible repression of enzyme synthesis by uracil.