tryptophan metabolic pathway hydrophobic amino acid degradation pathway tryptophan degradation pathway 2013-05-13T11:18:16Z PW:0001281 Those metabolic reactions involved in the degradation of tryptophan, an essential amino acid. Tryptophan undergoes oxidative catabolism carried out by several hemeprotein enzymes. In plants, tyrosine is the precursor for several secondary metabolites. Tryptophan catabolism pathway tryptophan catabolic process vpetri