Bacteriophage T5 deoxynucleoside monophosphate kinase (dNMP kinase, EC 2.7.4.13) is shown to catalyze the phosphorylation of both d2CMP and ribonucleotides AMP, GMP, and CMP, but does not phosphorylate UMP. For natural acceptors of the phosphoryl group, kmand kcatwere found. The applicability of T5 dNMP kinase as a universal enzyme capable of the phosphorylation of labelled r/dNMP was shown for the synthesis of [α-32P]rNTP and [α-32P]dNTP. © 2009 Pleiades Publishing, Ltd.