Inhibition of nucleic acid synthesis by folic acid antagonists.

Abstract

Aminopterin and A-methopterin, well known folic acid antagonists, have been shown to inhibit the incorporation of C14 from formate into nucleic acids and nucleic acid purines. Under the conditions of these experiments, incorporation of C14O2 into purines was partially blocked, but no decrease was observed in tissue CO2 fixation. The relationship of these observations to the mechanism of action of folic acid in purine synthesis and the anti-leukemic mechanism of “folic acid inhibitors” is discussed.