The prokaryotic cytidine monophosphate kinase specifically phosphorylates CMP (or dCMP), using ATP as the preferred phosphoryl donor. Unlike EC 126.96.36.199
, a eukaryotic enzyme that phosphorylates UMP and CMP with similar efficiency, the prokaryotic enzyme phosphorylates UMP with very low rates, and this function is catalysed in prokaryotes by EC 188.8.131.52
, UMP kinase. The enzyme phosphorylates dCMP nearly as well as it does CMP .