Aromatic Amino Acids

Aromatic amino acids (AAAs) are amino acids that include an aromatic ring. Tryptophan (Trp), Phenylalanine (Phe), and Tyrosine (Tyr) are aromatic amino acids (AAAs) required for protein biosynthesis in all living cells. Phenylalanine and tryptophan are essential amino acids for animals. Since they are not synthesized in the human body, they must be derived from the diet. Tyrosine is semi-essential; it can be synthesized, but only from phenylalanine. Animals obtain aromatic amino acids from their diet, but all plants and microorganisms must synthesize their aromatic amino acids through the metabolically costly shikimate pathway in order to make them.