The bacterial oxidation of tryptophan. III. Enzymatic activities of cell-free extracts from bacteria employing the aromatic pathway.

Analysis of the adaptive patterns of many tryptophan-oxidizing pseudomonads indicates that a majority of these organisms metabolize tryptophan via kynurenine, anthranilic acid, and catechol-the so-called "aromatic pathway" (Stanier, Hayaishi, and Tsuchida, 1951). In order to confirm the existence of this pathway, we have undertaken a study of the enzymatic activities of cellfree extracts. Only one previous investigation of the enzymes in pseudomonads that oxidize tryptophan by the aromatic pathway has been reported. Hayaishi and Hashimoto (1950) obtained a cell-free preparation that brought about the oxidation of catechol; the enzyme, named "pyrocatechase," was purified about 30-fold, and the product of the reaction with this purified system was identified as cis-cis-muconic acid.