Sulphur containing amino acid is/are

Based on the chemical structure of side chain (R), amino acids are classified into:- 1) Aliphatic amino acids:- Alanine, glycine, isoleucine, leucine, valine. 2) Hydroxy amino acids:- Serine, threonine, tyrosine. 3) Sulfur containing amino acids:- Cysteine, methionine. 4) Dicarboxylic amino acids:- Aspartic acid (aspartate), glutamic acid (glutamate). 5) Amide containing amino acids:- Glutamine, asparagine (these are amides of dicarboxylic amino acids. Glutamine is amide of glutamic acid and asparagine is amide of aspartic acid). 6) Aromatic amino acids:- Phenylalanine, tyrosine, tryptophan. 7) Amino acids or heterocyclic amino acids: - One of the 20 amino acids, proline is an amino (- NH) acid, not an amino (-NH2) acid, as are other 19.