Abstract
The enzyme 5-formyl tetrahydrofolate cyclodehydrase converts 5-formyl tetrahydrofolate to 5,10-methenyl tetrahydrofolate. A method has been devised for the cytochemical demonstration of this enzyme using 5-formyl tetrahydrofolate as substrate. The activity of the enzyme has been studied in leukocytes of children with acute leukaemia. Comparison of enzymatic activity in the same types of cells showed no significant variation between normal controls and the patients with acute leukaemia. The enzyme activity was found to increase with cell maturation and was strongly positive in polymorphonuclear leukocytes and eosinophils. The blast cells of patients with acute leukaemia were weakly positive or negative. This finding is of interest since the blast cells are capable of division. Two populations of lymphocytes were observed, one positive with a few granules and one negative. Methotrexate decreased enzyme activity in some patients; the enzyme may be a target for the action of folic acid antagonists.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tzortzatou, F., Zannos-Mariolea, L., Karayiannis, P. et al. 24 CYTOCHEMICAL DEMONSTRATION OF 5-FORMYL-TETRAHY-DROFOLATE CYCLODEHYDRASE ACTIVITY IN LEUCOCYTES OF PATIENTS WITH ACUTE LEUKAEMIA. Pediatr Res 13, 952 (1979). https://doi.org/10.1203/00006450-197908000-00040
Issue Date:
DOI: https://doi.org/10.1203/00006450-197908000-00040