Abstract
Abstract A kinase that catalyzes the phosphorylation of deoxycytidine has been purified 150-fold from L1210 murine leukemia cells. The reaction requires a divalent cation (preferably Mg++ or Mn++) and a nucleoside triphosphate. Optimal activity was obtained with ATP. Phosphorylation of deoxycytidine was competitively inhibited by both proximal (dCMP) and distal (dCDP and dCTP) end products and by cytosine arabinoside. Phosphorylation of the latter compound was also shown. Deoxycytidine kinase was relatively insensitive to —SH inhibitors and to surface active agents. An approximate molecular weight of 60,000 was found.
Highlights
SUMMARYA kinase that catalyzes the phosphorylation of deoxycytidine has been purified 150-fold from L1210 murine leukemia cells
Lscitic fluid containing tumor cells was removed from batches of 30 to 50 mice and collected in 200 ml of ice cold 0.9% NaCl containing 0.02 M Tris at I)H 7.4
The cells were collected by centrifugation at 1,000 x g for 10 min; contaminating erythrocytes were removed by resuspending the cell pellets in 0.20c KaCl for 30 set at 4”
Summary
A kinase that catalyzes the phosphorylation of deoxycytidine has been purified 150-fold from L1210 murine leukemia cells. Phosphorylation of deoxycytidine was competitively inhibited by both proximal (dCMP) and distal (dCDP and dCTP) end products and by cytosine arabinoside. Phosphorylation of the latter compound was shown. End product inhibition of deosynucleoside kinases has been rcl)orted [3] ; dcosythymidine kinase has been studied in detail [4,5,6,7], but only limited studies of deosycytidine kinase have been reported This enzyme is subject to regulation by nuclcotide products [3, 8]’ and has bcrnimplicated [8,9,10] in phosphorglatioll of cytosine arabinoside, an important antitumor agent. (2 C per mmole) was purchased from Schwarz Isioltesearch, Inc.; cytosine arabinoside-3H, tritiated (5 (’ per mmole) in the pyrimidine ring, was provided
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