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The Cysteine Molecule
Symbol: Cys C
Molecular Weight: 121.15
Isolectric point (pH) 5.02
Molecular Formula: C 3H7NO2 S


Cysteine is a naturally occurring hydrophilic ("water loving") amino acid which has a sulfhydryl (SH) group and is found in most proteins. When it is exposed to air it oxidizes to form cystine, which is two cysteine molecules joined by a disulfide bond. One molecule of water (H2O) is the byproduct from the creation of each molecule of cystine. Cysteine aids in Phase II Detoxification pathway in the liver. Cysteine also aids the metabolism of biochemicals such as heparin, biotin, coenzyme A and glutathione. Cysteine is plentiful in amaranth, cottage cheese, fish, poultry, shellfish, and soy products



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