ELABORATION OF PYRIMIDINE-SPECIFIC NUCLEOSIDASES BY HUMAN LYMPHOBLASTOID CELLS OF ESTABLISHED CULTURES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (8) , 2780-2784
Abstract
Pyrimidine-specific nucleosidases were released rapidly by human lymphoblastoid cells of established cultures when incubated under certain culture conditions having no adverse affect on their viability or morphology. Nucleosidase production was not restricted to any particular type of lymphoblastoid line; enzymes with a high level of activity were elaborated by cells of cultures initiated from healthy subjects and patients with uncontrolled lymphocytic or myelocytic leukemia, and by cells of cultures exhibiting mostly B [bone marrow-derived] or T [thymus-derived] cell properties. Tritiated thymine and uracil, which were not incorporated to any appreciable extent by DNA- and RNA-synthesizing cells, were identified by paper chromatography as the primary products arising from nucleosidase degradation of radiolabeled thymidine, uridine and cytidine. Neither adenosine nor guanosine was catabolized. These heat-labile and UV-sensitive enzymes with a MW of 5 to 10 .times. 104 did not affect the viability, morphology, or proliferation of lymphocytes in mitogen-activated cultures, lymphoblastoid cells in long-term cultures, or fibroblasts in monolayer cultures.