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Record Information
StatusDetected and Quantified
Creation Date2006-08-12 20:29:18 UTC
Update Date2020-02-26 21:24:36 UTC
Secondary Accession Numbers
  • HMDB03417
Metabolite Identification
Common NameD-Cysteine
DescriptionD-Cysteine, also known as D-cystein or DCY, belongs to the class of organic compounds known as cysteine and derivatives. Cysteine and derivatives are compounds containing cysteine or a derivative thereof resulting from reaction of cysteine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. It is a non-proteogenic sulfur-containing amino acid. D-Cysteine is known to be toxic to bacteria and several bacteria (and plants) have developed and enzyme called D-cysteine desulfhydrase (EC4.1.99.4). D-cysteine can be generated from D-Cysteine via cysteine racemase. D-Cysteine is a naturally occurring enantiomer of L-Cysteine. Cysteine is named after cystine, which comes from the Greek word kustis meaning bladder − cystine was first isolated from kidney stones. D-Cysteine is a very strong basic compound (based on its pKa). D-Cysteine exists in all living species, ranging from bacteria to humans. Outside of the human body, D-Cysteine has been detected, but not quantified in, several different foods, such as chervils, fruits, lichee, nuts, and cherimoya. This could make D-cysteine a potential biomarker for the consumption of these foods. This enzyme decomposes D-cysteine into pyruvate, H2S, and NH3.
(2S)-2-Amino-3-mercaptopropanoic acidChEBI
(2S)-2-Amino-3-sulfanylpropanoic acidChEBI
(S)-2-Amino-3-mercaptopropanoic acidChEBI
D-Amino-3-mercaptopropionic acidChEBI
(2S)-2-Amino-3-sulphanylpropanoic acidGenerator
Half cystineHMDB
Cysteine hydrochlorideHMDB
L CysteineHMDB
Zinc cysteinateHMDB
Chemical FormulaC3H7NO2S
Average Molecular Weight121.15
Monoisotopic Molecular Weight121.019749643
IUPAC Name(2S)-2-amino-3-sulfanylpropanoic acid
Traditional NameL cysteine
CAS Registry Number921-01-7
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as cysteine and derivatives. Cysteine and derivatives are compounds containing cysteine or a derivative thereof resulting from reaction of cysteine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentCysteine and derivatives
Alternative Parents
  • Cysteine or derivatives
  • Alpha-amino acid
  • D-alpha-amino acid
  • Amino acid
  • Alkylthiol
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Organic oxygen compound
  • Primary amine
  • Organosulfur compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic nitrogen compound
  • Primary aliphatic amine
  • Carbonyl group
  • Amine
  • Hydrocarbon derivative
  • Organopnictogen compound
  • Organic oxide
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors

Route of exposure:


Biological location:


Industrial application:

Physical Properties
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility23.1 g/LALOGPS
pKa (Strongest Acidic)2.35ChemAxon
pKa (Strongest Basic)9.05ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count3ChemAxon
Polar Surface Area63.32 ŲChemAxon
Rotatable Bond Count2ChemAxon
Refractivity28.22 m³·mol⁻¹ChemAxon
Polarizability11.4 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-004l-9100000000-4553906a941a5e87ec97Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-004i-9200000000-cfaf705cd0452d428454Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, N/A (Annotated)splash10-056r-9300000000-ed3d829a54e4ac06325dSpectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, N/A (Annotated)splash10-0a4i-9000000000-224425097c9b1883d266Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, N/A (Annotated)splash10-0a4i-9000000000-39cb21d5fd8f893ba8fdSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-00b9-9600000000-4352a7b437c34c04d9f0Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-004i-9200000000-7b4cd034c717561c61ddSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-052f-9000000000-8f351cbca6ffed356a9bSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-00di-6900000000-51ba0df80cc33423420bSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0079-9400000000-4aa2b707c391d5838d29Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-001i-9000000000-95c7672c7836c0fc51c9Spectrum
1D NMR1H NMR SpectrumNot AvailableSpectrum
2D NMR[1H,13C] 2D NMR SpectrumNot AvailableSpectrum
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biospecimen Locations
  • Saliva
Tissue LocationsNot Available
Normal Concentrations
SalivaDetected and Quantified8.643 +/- 2.11 uMAdult (>18 years old)BothNormal
    • Zerihun T. Dame, ...
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB03201
Phenol Explorer Compound IDNot Available
FooDB IDFDB023168
KNApSAcK IDC00007323
Chemspider ID83819
KEGG Compound IDC00793
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkCysteine
METLIN IDNot Available
PubChem Compound92851
PDB IDNot Available
ChEBI ID16375
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB ID
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Tsukamoto S, Kanegae T, Nagoya T, Shimamura M, Mieda Y, Nomura M, Hojo K, Okubo H: Effects of amino acids on acute alcohol intoxication in mice--concentrations of ethanol, acetaldehyde, acetate and acetone in blood and tissues. Arukoru Kenkyuto Yakubutsu Ison. 1990 Oct;25(5):429-40. [PubMed:2275637 ]
  2. Riemenschneider A, Wegele R, Schmidt A, Papenbrock J: Isolation and characterization of a D-cysteine desulfhydrase protein from Arabidopsis thaliana. FEBS J. 2005 Mar;272(5):1291-304. [PubMed:15720402 ]