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Thymidylate synthetase and dihydrofolic acid reductase in the stimulated human lymphocyte
Author(s) -
Haurani Farid I.,
Kardinal Carl G.,
Biermann William A.
Publication year - 1978
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040950107
Subject(s) - thymidylate synthase , lymphocyte , reductase , biochemistry , chemistry , enzyme , microbiology and biotechnology , biology , genetics , cancer , fluorouracil
The phytohemagglutinin (PHA)‐stimulated human lymphocytes demonstrated trace or no activity of (dihydro) folate acid reductase using three methods including a radioassay, but demonstrated ample activity of thymidylate synthetase. This was true regardless of the day of harvest, (first through seventh) of the stimulated lymphocyte. The lymphocyte extracts revealed no inhibitor to the reductase enzyme when these extracts were added before the liver extracts to the assay system. When methotrexate (MTX) was added to the culture media of the lymphocytes, there was, as expected, an increase in the synthetase activity, but the expected rise in the reductase activity did not occur, it remained nil. On the other hand, MTX did influence the incorporation of nucleosides by the stimulated lymphocytes in a fashion similar to its action on the incorporation of the same nucleosides by other cells.