The prokaryotic cytidine monophosphate kinase specifically phosphorylates CMP (or dCMP), using ATP as the preferred phosphoryl donor. Unlike EC 18.104.22.168
, 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 22.214.171.124
, UMP kinase. The enzyme phosphorylates dCMP nearly as well as it does CMP .