Anthranilic acid oxidase system of Tecomastans - III. Studies on the conversion of ο-aminophenol to catechol

Abstract

The terminal step in the oxidation of anthranilic acid to catechol by anthranilic acid oxidase system from Tecoma stans, which converts ο-aminophenol to catechol has been studied in detail. The reaction catalyses the conversion of one molecule of ο-aminophenol to one molecule each of ammonia and catechol. The partially purified enzyme has a ρH optimum of 6.2 in citrate-phosphate buffer and a temperature optimum of 45° . The metal ions, Mg²⁺, Co²⁺ and Fe³⁺ were inhibitory to the reaction. Metal chelating agents like 8-hydroxyquinoline, ο-phenanthroline, and diethyldithiocarbamate, caused a high degree of inhibition. A sulfhydryl requirement for the reaction was inferred from the inhibition of the reaction by ρ-chloromercuribenzoate and its reversal with GSH. Atebrin inhibition was reversed by addition of FAD to the reaction mixture.