There are two major source of human dietary sulfur containing amino acids. One them is L-cysteine, a sulfur containing amino acid with the thiol side-chain, which is involved in metal-binding in proteins.
L-methionine is another proteic amino acid that possesses sulfur in its molecule.
From L-cysteine and L-methionine the body builds the essential compounds coenzyme A, heparin, glutathione, lipoic acid and biotin.
The disulfide bonds of the sulfur containing amino acids are largely responsible or determining the tertiary structure of proteins.
Cystine
Cystine is the stable form of the sulfur rich amino cysteine. The body is capable of converting one of the other as required.The sulfur in cysteine molecules plays a crucial role in folding proteins into their correct shapes. For examples sulfur independent proteins are keratin – part of hair, skin and nails and collagen – part of connective tissue like cartilage.
Methionine
Methionine, an essential amino acid, is an important source of sulfur. It is required for DNA-RNA structure, collagen and each cell’s protein syntheses function.Methionine helps remove heavy metals from the tissues. For example, lead is one heavy metal which causes brain damage.
It helps to control fat levels in the blood and aids in preventing the buildup of cholesterol on the artery walls.
Sulfur in amino acids
