Amino acids Structures for presentation: Amino acids are 20,which are involved in protein synthesis. they are Gl ycine, Alanine, Valine, Leucine and Isoleuine, Arginine, Lysine, Glutamic acid, Aspartic acid, Cysteine, Phenylalanine, Tyrosine, Tryptophan, Proline, Hydroxyproline, Serine, Threonine.