Inhibition of Dihydrofolic Reductase by Aminopterin and Amethopterin.

Abstract

SummaryThe enzyme, dihydrofolic reductase, which catalyzes the TPNH-linked reduction of dihydrofolic acid to tetrahydrofolic acid, is inhibited non-competitively by the folic acid antagonists, Aminopterin and Amethopterin. Values of 1 × 10-9 M and 2.3 × 10-9 M were obtained for the inhibitor constants (KI) of Aminopterin and Amethopterin, respectively.