L-cysteine is a protein amino acid naturally present in the proteins
of life forms. L-cysteine is a sulfur amino acid and contains a sulfhydryl
group. Although most cysteine is found in proteins, small amounts of free
cysteine are found in body fluids and in plants. The normal diet contributes
approximately 1 gram of L-cysteine daily.
L-cysteine is considered a nonessential amino acid, meaning that, under
normal physiologic conditions, sufficient amounts of this amino acid are
formed from the dietary essential amino acids L-methionine and the nonessential
amino acid L-serine via a transsulfuration reaction. L-cysteine is a conditionally
essential amino acid under certain circumstances, for example, for preterm
infants.
L-cysteine serves as a very important precursor for synthesis of proteins,
glutathione, taurine, coenzyme A, and inorganic sulfate. Glutathionine
itself has a number of biochemical functions, including maintenance of
normal cellular redox state. Certain conditions, e.g. an acetaminophen
overdose, can deplete hepatic glutathione, and this can be life-threatening.
The antidote to an acetaminophen overdose is L-cysteine, in the delivery
form of N-acetylcysteine. The L-cysteine derived from N-acetylcysteine
helps to restore hepatic glutathione. See N-acetylcysteine Overview.
(Source: www.pdrhealth.com)
Research Overview
Research on L-cysteine shows the following effects:
1. Prevents liver fibrosis
2. Has cytoprotective properties against toxicity
3. May modulate KYNA development in the brain
4. Prevents cataract formation
5. May help prevent ischemia-reperfusion injury in the lung
6. Cysteine deficiency leads to cellular dysfunction in HIV
7. Lowers blood, brain and liver alcohol levels caused by alcohol intoxication
8. Combats severe hypoglycemic attacks
9. May be a factor in cardiovascular control
10. May play a role in heavy metal detoxification
L-Cysteine
Abstracts (31)
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