SEARCH Articles Figures Tables Amino Acid Tryptophan Indole Alkaloids and Derivatives Amino acid tryptophan dioxygenase Amino acids Tryptophan (Trp Amino-acid residues tryptophan Aromatic Amino Acids Phenylalanine, Tyrosine, Histidine, and Tryptophan Intrinsic amino acid tryptophan probes Intrinsic amino acid tryptophan probes protein Tryptophan amino acids liberated from Tryptophan essential amino acid Tryptophan synthase, aromatic amino acid Tryptophan synthase, aromatic amino acid biosynthesis