Purification and Properties of Dihydrofolate Reductase from Ehrlich Ascites Carcinoma Cells^*

Folate metabolism in man: the effect of malignant disease

“…10-Formylfolate is known to inhibit the reduction of folic acid and dihydrofolate by mammalian dihydrofolate reductase (E.C. 1.5.1.3) in vitro (Bertino et al, 1965;Friedkin et al, 1975;A. Sahota, personal communication).…”

“…10-Formylfolate, an oxidized folate, is an important constituent of food folate (Butterworth et al, 1965;Santini et al, 1964). However, it is not reduced by Ehlrich ascites carcinoma (Bertino et al, 1965) or bovine dihydrofolate reductase (A. Sahota, personal communication) and therefore may not be available to mammals. Earlier investigations by Ratanasthien et al (1974), using a microbiological assay, showed no metabolism of orally administered 10-formylfolate by man.…”

Modulation of One-Carbon Metabolism by B Vitamins: Implications for Transformation and Progression of Prostate Cancer

“…As discussed by Kisliuk, oxidation of the pteridine ring from the active tetrahydro to the dihydro state can change a stimulatory coenzyme to a powerful anti-fol (Kisliuk, 1981). 10-formylfolic acid is a potent inhibitor of dihydrofolate reductase of rat liver slices (Rauen et al, 1952;Bertino et al, 1965;D'Urso-Scott et al, 1974;Friedkin et al, 1975;Rauen et al, 1952;Silverman et al, 1954). However, the literature is inconsistent concerning the in vivo activity of 10-formylfolic acid in man.…”

Effect of folic acid by mouth on cerebrospinal fluid homovanillic acid and 5-hydroxyindoleacetic acid concentration

“…This cofactor may be formed by reduction of 7,8-dihydrofolic acid through the action of dihydrofolic acid reductase. Folic acid is a competitive inhibitor of this enzyme (Bertino, Perkins, and Johns, 1965), though its action is much weaker than that of folate analogues in clinical use. Blair (1970) Auletta, Mead, and Waravdekar (1970) who found that when mice were injected with 300 mg folic acid per kilogram body weight their kidney dihydrofolic acid reductase activity fell by 80% within 10 minutes and that low activity persisted for 72 hours.…”