The metabolism of tryptophan and 7-chlorotryptophan in Pseudomonas pyrrocinia and Pseudomonas aureofaciens.

Pseudomonas pyrrocinia ATCC 15958 and a mutant strain (ACN) of Pseudomonas aureofaciens ATCC 15926 possess a mechanism for the degradation of the tryptophan side chain. Indole, indole-3-carboxylic acid, indole-3-acetic acid and the corresponding compounds chlorinated or brominated at position 7, as well as indole-3-pyruvate and 7-chloroindole-3-pyruvate, were isolated from bacterial cultures. The chlorinated indole derivatives were isolated after the addition of 7-chloro-DL-tryptophan to cultures of P. pyrrocinia whereas their bromo analogues were found in the culture medium of the mutant strain ACN of P. aureofaciens, grown in the presence of sodium bromide. Enzymatic studies show that tryptophan is transaminated to indole-3-pyruvate, which is transformed to indole-3-acetaldehyde. Dehydrogenation of indole-3-acetaldehyde leads to indole-3-acetic acid, which is further metabolized to indole-3-carboxaldehyde, and converted by dehydrogenation to indole-3-carboxylic acid. Indole is formed by the spontaneous decarboxylation of indole-3-carboxylic acid.