Abstract
Summary
An in vitro assay measuring AMP: and IMP: pyrophosphate phosphoribosyltransferase (EC 2.4.2.7 and EC 2.4.2.8) levels in intact leukocytes has been described. Intact erythrocytes incorporate insignificant amounts of precursor compared with leukocytes. The mean level of IMP pyrophosphate phosphoribosyltransferase in leukocytes from nine patients with acute myelogenous leukemia in relapse was significantly higher (0.01<p>0.001)) than in normal leukocytes. The levels of leukocyte AMP: pyrophosphate phosphoribosyltransferase were higher in leukemics but not significantly so compared with normal values. No significant reduction of IMP: pyrophosphate phosphoribosyltransferase activity was observed in leukocytes from leukemics clinically resistant to purine analogs. No correlation could be found between leukocyte enzyme activity and relapse, remission or therapy of leukemia. Enzyme levels in leukocytes isolated from patients with other malignancies were in the normal range. However, in a number of leukemics with apparently normal differential blood smears, the enzyme activities of the nonleukemic cells were greater than normal.
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