Pyrimidine nucleoside monophosphate kinase isolated from pig brain homogenate catalyzes disproportionation of phosphate between two CDP molecules.

An enzyme fraction that catalyzes CTP formation from CDP was purified from pig brain homogenate to a single band on SDS-PAGE. The preparation had a molecular weight of about 36,000 and showed a high activity of phosphorylating CMP and UMP by ATP and turned out to be one of pyrimidine nucleoside monophosphate kinases. It also catalyzes UTP formation from UDP, although rather weakly. These characteristics show that the enzyme species from pig brain homogenate has a rather broad specificity toward phosphate donor in phosphorylating nucleoside monophosphate.