L-Tryptophan catabolism by Rubrivivax benzoatilyticus JA2 occurs through indole 3-pyruvic acid pathway

Abstract

Rubrivivax benzoatilyticus JA2 utilizes l-tryptophan as the sole source of nitrogen for growth, and it has a doubling time of ~11 h (compared to 8 h with ammonium chloride). With cell free extracts in the presence of 2-oxoglutarate, indole-3-pyruvic acid, indole-3-acetaldehyde, indole-3-acetic acid, isatin, benzaldehyde, gallic acid and pyrogallol were identified using high performance liquid chromatography (HPLC) and liquid chromatography-mass spectroscopy (LC-MS) analysis. The conversion of l-tryptophan into indole 3-pyruvic acid and glutamate by an enzyme aminotransferase was confirmed and the catabolism of indole-3-pyruvic acid via side chain oxidation followed by ring oxidation, gallic acid and pyrogallol were confirmed as metabolites. In addition, the proposed pathway sequential conversion of indole-3-pyruvic acid to the end product of pyrogallol was identified, including an enzymatic step that would convert isatin to benzaldehyde by an enzyme yet to be identified. At this stage of the study, the enzyme tryptophan aminotransferase in R. benzoatilyticus JA2 was demonstrated. © 2010 Springer Science+Business Media B.V.