The Effect of Folic Acid on the Toxicity of Its Analogue

E VER since Woods’ described a competition between sulfanilamide and paraaminobenzoic acid for an enzyme system related to the use of this vitamin in metabolic processes, widespread interest has centered on the synthesis of analogues which are chemically related to a metabolite but which seriously interfere with its normal function. There are now available a large number of these metabolite antagonists’ which in very minute amounts seriously interfere with the functions ofcell catalysts, such as vitamins and hormones. Such antagonists or displacing agents have now been synthesized for every known member of the vitamin B-complex. Martin, Tolman and Moss3 prepared the first antagonist to pteroylglutamic acid. They produced methylfolic acid, which was shown to be an effective displacer of folic acid with a ratio of inhibitor to metabolite of i : iso. The growth-promoting action of pteroylglutamic acid