Nucleoside and nucleotide kinases are phospho-transferases catalyzing the addition of phosphate groups to the 5'-end of nucleosides or nucleotides. ATP or other NTPs can serve as phosphate donors.

Nucleoside kinases (NKs, EC 2.7.1.x) perform the irreversible transfer of a phosphate group from ATP (or other NTPs) to the 5'-end of nucleosides to form nucleoside monophosphates.

Nucleoside monophosphate kinases (NMPKs, EC 2.7.4.x) catalyze the reversible transfer of a phosphate group from ATP (or other NTPs) to the 5'-end of nucleoside monophosphates to form nucleoside diphosphates. Additionally, many NMPKs show little NDPK activity. 

Nucleoside diphosphate kinases (NDPKs, EC 2.7.4.6) catalyze the reversible transfer of a phosphate group from ATP (or other NTPs) to the 5'-end of nucleoside diphosphates to form nucleoside triphosphates.

Substrate spectra differ greatly between kinases. There are rather specific enzymes like thymidine kinase (TK, EC 2.7.1.21) from Escherichia coli as well as wide spectrum biocatalysts like deoxynucleoside kinase (dNK, EC 2.7.1.145) from Drosophila melanogaster which accepts all natural deoxynucleosides and many nucleoside analogs as substrates. Furthermore, the optimal reaction temperature ranges from moderate to high depending on the organism the enzyme originates from.

By combining a NK, a NMPK and a NDPK, the enzymatic synthesis of natural and modified nucleoside triphosphates (NTPs) is possible in a one-pot, three enzyme reaction. The incorporation of an ATP regeneration system might significantly enhance product yields and shorten reaction times.

If you need detailed information on the temperature activity range or suitable enzyme combinations please contact us or check out our enzyme activity screening service.