Deoxycytidine kinase regulation

There are several points of regulation in the synthesis. For example, dCTP inhibits the salvage reaction catalyzed by deoxycytidine kinase and activates the reaction catalyzed by dCMP deaminase. On the other hand, dTTP inhibits the dCMP deaminase reaction and the enzyme thymidine kinase. 

Ives, D.H. Durham, J.P. Deoxycytidine kinase. 3. Kinetics and allosteric regulation of the calf thymus enzyme. J. Biol. Chem., 245, 2285-2294 (1970)... 

Kim, M.-Y. Ives, D.H. Hiunan deoxycytidine kinase kinetic mechanism and end product regulation. Biochemistry, 28, 9043-9047 (1989)... 

Usova, E.V. Eriksson, S. The effects of high salt concentrations on the regulation of the substrate specificity of human recombinant deoxycytidine kinase. Eur. J. Biochem., 248, 762-766 (1997)... 

The kinase which converts deoxycytidine to its 5 -monophosphate has been studied most extensively in preparations from calf thymus 35, 36). The preferred substrate is deoxycytidine, for which the Michaelis constant (5 X 10 M) is much lower than that of two other substrates, deoxyadenosine and deoxyguanosine. Cytidine, uridine, and thymidine are not phosphorylated by this enzyme. Deoxycytidine kinase is subject to a complex pattern of allosteric regulation by nucleotides. The end product of deoxycytidine phosphorylation, dCTP, is a potent inhibitor this inhibition is reversed by dTTP. The enzyme has a rather broad specificity for the phosphate donor, with the triphosphates of the natural ribo- and deoxyribonucleosides being substrates the inactivity of dCTP is a notable exception. 

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