Sulfur Containing Amino Acids z Methionine (Met, M) – “start” amino acid, very hydrophobic z Cysteine (Cys,C) – sulfur in form of sulfhydroyl, important in disulfide linkages, weak acid, can form hydrogen bonds.Sulfur Containing Amino Acids z Methionine (Met, M) – “start” amino acid, very hydrophobic z Cysteine (Cys,C) – sulfur in form of sulfhydroyl, important in disulfide linkages, weak acid, can form hydrogen bonds