All are aromatic amino acids EXCEPT:

(Lysine): Ref 49, U.S. (75- R.S. 7th)* Aromatic amino acids: Phenylalanine, tyrosine and tryptophan (with indole ring) are aromatic amino acids, Basides these histidine may also be considered this category.* Hydroxyl group containing amino acids: - Serine, Threonine, Tyrosine* Amino acids with aliphatic side chains: - Leucine, Isoleucine, Valine {Branchedchain amino acids) Glycine, Alanine* Basic amino acids: - Lysine, Arginine {with guanidine group) and Histidine {imidazole ring)* Non polar amino acids: - Alanine, laucine, Isoleucine, Valine, Methionine, Phenylalanine, tryptophan and proline