Purification and Properties of Cytidine Deaminase from Normal and Leukemic Granulocytes

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Abstract

Cytidine deaminase, an enzyme that catalyses the deamination of both cytidine and its nucleoside analogues including the antineoplastic agents cytosine arabinoside (ara-C) and 5-azacytidine (5-azaC), has been partially purified from normal and leukemic human granulocytes. The purification procedure included heat precipitation at 70°C, ammonium sulfate precipitation, calcium phosphate gel ion exchange, and Sephadex G-150 gel filtration. The enzyme has mol wt 51,000, isoelectric pH of 4.8, and maximum activity over a broad pH range of 5-9.5. The enzyme is stabilized by the presence of the sulfhydryl reagent, dithiothreitol.

Authors

Bruce A. Chabner, David G. Johns, C. Norman Coleman, James C. Drake, Warren H. Evans