Studies on the metabolic pathway of anthranilic acid in rats

Recent experiments with administration of anthranilic acid in rats afforded two new metabolites; anthranilamide and a light blue fluorescent substance. Administration of anthranilamide to rats resulted in urinary excretion of two main metabolites which were isolated from urine as 3-hydroxyanthranilamide-O-sulfate and 5-hydroxyanthranilamide-O-sulfate. This fact showed that anthranilamide is hydroxylated and then conjugated in vivo. Hydroxylation of anthranilamide was found to be catalyzed by drugs hydroxylation system but not by the microsomes alone, and is a specific reaction activated by a protein component contained in the soluble fraction. The purified protein component was recongneized that it was bluish green protein containing copper and zinc, and its molecular weight was 25,700. This protein component had no effect on the metabolism of drugs by liver microsomes but showed specific activation of hydroxylation of 2-aminobenzoyl compounds.