Amino acids, alphabetically: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine. Stylized skeletal formula (chemical structure). Atoms are shown as color-coded circles: hydrogen (hidden), carbon (grey), nitrogen (blue), oxygen (red), sulfur (yellow).