RT Journal Article
SR Electronic
T1 Deoxycytidine Kinase
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 358
OP 375
VO 5
IS 4
A1 JOHN P. DURHAM
A1 DAVID H. IVES
YR 1969
UL http://molpharm.aspetjournals.org/content/5/4/358.abstract
AB Deoxycytidine kinase is confined primarily to lymphoid tissues in the rat and mouse. Its activity varies widely, with highest levels in the thymus. A similar range of activities was found among the tumors examined. There is not an exact correlation of kinase activity with the cell proliferation rate. In crude tissue extracts the phosphorylation of cytosine arabinoside (araC) is inhibited to a variable and greater extent than the phosphorylation of deoxycytidine (CdR), and this inhibition is largely removed by dialysis of the preparations. Partially purified CdR kinase from calf thymus phosphorylates CdR, araC, GdR, and AdR, with CdR being the kinetically preferred substrate. Each of these nucleosides will competitively inhibit the phosphorylation of any of the others. Enzymatic activity is also inhibited by a number of nucleotides at physiological concentrations, and in each case the phosphorylation of araC is more sensitive to the inhibition than that of CdR, dTTP, dUTP, and UTP, which themselves inhibit phosphate transfer from ATP, nonetheless will partially reverse the very potent inhibition of dCTP. The preferential inhibition of araC phosphorylation in extracts is therefore tentatively explained in terms of complex interactions of a number of nucleosides and nucleotides with the enzyme, all of which tend to select for phosphorylation of CdR. ACKNOWLEDGMENT We thank Miss Delia de Leon for excellent technical assistance.