Action of some substituted anthranilic acids on Escherichia coli.

Rydon (1) has found that 4and 5-methylanthranilic acids inhibit the growth of Eberthella typhi and that this inhibition is reversed by anthranilic acid, indole, and tryptophan. He concluded that the two methyl compounds interfere with the synthesis of tryptophan at the stage of anthranilic acid. Interruption in the conversion of anthranilic acid to indole in Escherichia coli, caused by chloromycetin, aureomycin, and Terramycin, was recently observed by Bergmann and Sicher (2) and Bergmann et al. (3). The same effect is shown by 5-fluorotryptophan (4).’ It appeared, therefore, interesting to study the response of E. coli to some substituted anthranilic acids. Since the fluoro compounds o-, m-,’ p-fluorophenylalaninel (5) and 3-fluorotyrosine (6, 7) were found to exert antimetabolite activity, 4and 5-tluoroanthranilic acids in addition to 5-methylanthranilic acid were chosen as possible antimetabolites. The present study shows that these anthranilic acid analogues do indeed inhibit the biosynthesis of anthranilic acid in E. COG, and that the inhibition can be overcome not only by the similarly built metabolites, but also by a number of amino acids, purines, and vitamins.