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L-Cysteine

File:L-Cystein_-_L-Cysteine.svg · Wikimedia Commons · See Wikimedia Commons

EntityQ186474· pop 61· linked from 1,689 articles

L-Cysteine

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Also known as L-Cys, (2R)-2-amino-3-sulfanylpropanoic acid, (R)-2-amino-3-mercaptopropanoic acid, FREE CYSTEINE, (2R)-2-amino-3-mercaptopropanoic acid, E920, E-920, E 920

thumb|Cysteine ball and stick model spinning Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine enables the formation of disulfide bonds, and often participates in enzymatic reactions as a nucleophile. Cysteine is chiral, but both D and L-cysteine are found in nature. LCysteine is a protein monomer in all biota, and D-cysteine acts as a signaling molecule in mammalian nervous systems. Cysteine is named after its discovery in urine, which comes from the urinary bladder or cyst, from Greek κύστις kýstis, "bladder".

OverviewAI-generated

L-Cysteine is a chemical compound with the formula C₃H₇NO₂S. Its IUPAC name is (2R)-2-amino-3-sulfanylpropanoic acid. The substance has a mass of 121.02 and a weight of 121.16. It possesses a pKa of 1.96 and a solubility of 1.5. The MCN code for this compound is 2930.90.12.

Chemical properties include an xlogp of -2.5 and a topological polar surface area of 64.3. The molecule has three hydrogen bond donors and four hydrogen bond acceptors, with a charge of 0. Its canonical SMILES notation is C(C(C(=O)O)N)S, while the isomeric SMILES is N[C@@H](CS)C(O)=O. The InChIKey is XUJNEKJLAYXESH-REOHCLBHSA-N.

L-Cysteine is associated with 167197 PubMed entries. It is referenced by 1,689 other encyclopedia articles. The NCI Thesaurus ID for the compound is C29609.

Synthesized by Vinony from 22 facts across 4 sources: Wikidata, PubChem, PubMed, Vinony graph. Generated from structured data (not the Wikipedia text) and checked against those facts — may still contain errors.

Chemical data

Formula
C3H7NO2S
Molecular weight
121.16 g/mol
IUPAC name
(2R)-2-amino-3-sulfanylpropanoic acid
SMILES
C([C@@H](C(=O)O)N)S
InChIKey
XUJNEKJLAYXESH-REOHCLBHSA-N
XLogP
-2.5
Polar surface area
64.3 Ų
H-bond donors
3
H-bond acceptors
4
Formal charge
0

via PubChem

Research

167,197 papers

via PubMed

~14 min read

Encyclopedic overview

22 sections
Contents
  • Structure
  • Dietary sources
  • Industrial sources<span class="anchor" id="Dietary restrictions"></span>
  • Biosynthesis
  • Biological functions
  • Precursor to the antioxidant glutathione
  • Precursor to iron-sulfur clusters
  • Metal ion binding
  • Roles in protein structure
  • Evolutionary role of cysteine
  • Applications
  • Reducing toxic effects of alcohol
  • ''N''-Acetylcysteine
  • D-ribose L-cysteine
  • Sheep
  • Chemical reactions
  • Safety
  • History
  • See also
  • References
  • Further reading
  • External links

thumb|Cysteine ball and stick model spinning Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine enables the formation of disulfide bonds, and often participates in enzymatic reactions as a nucleophile. Cysteine is chiral, but both D and L-cysteine are found in nature. LCysteine is a protein monomer in all biota, and D-cysteine acts as a signaling molecule in mammalian nervous systems. Cysteine is named after its discovery in urine, which comes from the urinary bladder or cyst, from Greek κύστις kýstis, "bladder".

The thiol is susceptible to oxidation to give the disulfide derivative cystine, which serves an important structural role in many proteins. In this case, the symbol Cyx is sometimes used. The deprotonated form can generally be described by the symbol Cym as well.

Excerpted from Wikipedia’s “L-Cysteine” article, available under the CC BY-SA 4.0 licence.

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