Tryptophan metabolism by a papaverine-degrading Nocardia sp.

Tryptophan catabolism was studied in a papaverine-degrading Nocardia sp. L-Tryptophan degradation follows the quinoline route via kynurenic acid. 5-(2-Carboxyethyl)-4,6-dihydroxypicolinic acid was isolated as a kynurenic acid metabolite. Mutants were induced with N-methyl-N'-nitro-N-nitrosoguanidine. A mutant was isolated, which accumulated 5-hydroxyanthranilic acid. There is no relationship between kynurenic acid degradation and papaverine degradation. All kynurenic acid mutants were able to use papaverine as a carbon source and all papaverine mutants could be grown at the expense of kynurenic acid.