Cytidine deaminase activity of human normal and malignant lymphoid cells
1985; Elsevier BV; Volume: 147; Issue: 2 Linguagem: Inglês
10.1016/0009-8981(85)90066-x
ISSN1873-3492
AutoresJean‐Louis Pérignon, Jacques Chaléon, Guy Leverger, Anne‐Marie Houllier, Laure Thuillier, P Cartier,
Tópico(s)Transgenic Plants and Applications
ResumoCytidine deaminase activity was determined by a radioisotopic assay in extracts of peripheral blood mononuclear cells of normal individuals and of patients with acute lymphoblastic leukaemia. The normal enzyme activity had a broad pH optimum between pH 6.5 and 8.0; apparent Km values for cytidine and deoxycytidine were 3.6 ± 0.6 μmol/l and 26.5 ± 3.5 μmol/l, respectively; the activity was resistant to heat inactivation; of the various effectors tested, only uridine, deoxyuridine and tetrahydroxyuridine had inhibitory effects. Cytidine deaminase activity was markedly decreased in lymphoblasts of patients with acute lymphoblastic leukaemia; enzyme activity was related to the percentage of circulating blast cells, and not to the clinical, cytological or immunological characters of the leukaemia.
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