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Record Information
StatusExpected but not Quantified
Creation Date2006-08-13 00:53:44 UTC
Update Date2017-12-07 01:52:37 UTC
Secondary Accession Numbers
  • HMDB0006337
  • HMDB03585
  • HMDB06337
Metabolite Identification
Common NameThiocysteine
DescriptionThe reactive species in the phosphofructokinase modulation system could be considered thiocysteine (R-S-S-) or cystine trisulfide (R-S-S-S-R) produced from cystine in the presence of gamma-Cystathionase (CST, EC The desulfuration reaction of cystine in vivo produces thiocysteine containing a bound sulfur atom. Persulfide generated from L-cysteine inactivates tyrosine aminotransferase. Thiocysteine is the reactive (unstable) intermediate of thiocystine which functions as a persulfide in transferring its sulfane sulfur to thiophilic acceptors. Thiocystine conversion to unstable thiocysteine is accelerated by sulfhydryl compounds, or reagents that cleave sulfur-sulfur bonds to yield sulfhydryl groups. Thiocystine is proposed as the storage form of sulfane sulfur in biological systems. Liver cytosols contain factors that produce an inhibitor of tyrosine aminotransferase in 3 steps: initial oxidation of cysteine to form cystine; desulfurization of cystine catalyzed by cystathionase to form the persulfide, thiocysteine; and reaction of thiocysteine (or products of its decomposition) with proteins to form protein-bound sulfane. (PMID: 2903161 , 454618 , 7287665 ).
Chemical FormulaC3H7NO2S2
Average Molecular Weight153.223
Monoisotopic Molecular Weight152.991819853
IUPAC Name(2S)-2-amino-3-disulfanylpropanoic acid
Traditional Name(2S)-2-amino-3-disulfanylpropanoic acid
CAS Registry Number5652-32-4
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as cysteine and derivatives. These 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
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Sulfenyl compound
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Organic oxide
  • Primary amine
  • Organosulfur compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organopnictogen compound
  • Primary aliphatic amine
  • Organic oxygen compound
  • Carbonyl group
  • Amine
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External DescriptorsNot Available


Physical Properties
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogP-1.917Not Available
Predicted Properties
Water Solubility14.3 g/LALOGPS
pKa (Strongest Acidic)2.04ChemAxon
pKa (Strongest Basic)8.9ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count3ChemAxon
Polar Surface Area63.32 ŲChemAxon
Rotatable Bond Count3ChemAxon
Refractivity33.99 m³·mol⁻¹ChemAxon
Polarizability14.19 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectrum TypeDescriptionSplash Key
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-002f-9200000000-2698595247d44144b386View in MoNA
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00di-9300000000-df6a4d15744f12f2dc0fView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-052r-5900000000-cebf11d68c2df85b1cc8View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0a6r-5900000000-9adeada6729d7a30cbb0View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0006-9000000000-c9351f3fcc5c9de3b7e3View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0f79-9700000000-8561e1934a1ae7f329e1View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0fni-9200000000-df6a2ea2c3d324acdedbView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-00di-9000000000-a4fc4e46a9085d75f7e5View in MoNA
Biological Properties
Cellular LocationsNot Available
Biospecimen LocationsNot Available
Tissue LocationNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FoodDB IDFDB023203
KNApSAcK IDNot Available
Chemspider IDNot Available
KEGG Compound IDC01962
BiGG ID38786
Wikipedia LinkNot Available
METLIN IDNot Available
PubChem Compound439614
PDB IDNot Available
ChEBI ID28839
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. Hargrove JL: Persulfide generated from L-cysteine inactivates tyrosine aminotransferase. Requirement for a protein with cysteine oxidase activity and gamma-cystathionase. J Biol Chem. 1988 Nov 25;263(33):17262-9. [PubMed:2903161 ]
  2. Abdolrasulnia R, Wood JL: Transfer of persulfide sulfur from thiocystine to rhodanese. Biochim Biophys Acta. 1979 Mar 16;567(1):135-43. [PubMed:454618 ]
  3. Yamanishi T, Tuboi S: The mechanism of the L-cystine cleavage reaction catalyzed by rat liver gamma-cystathionase. J Biochem. 1981 Jun;89(6):1913-21. [PubMed:7287665 ]


General function:
Involved in pyridoxal phosphate binding
Specific function:
Catalyzes the last step in the trans-sulfuration pathway from methionine to cysteine. Has broad substrate specificity. Converts cystathionine to cysteine, ammonia and 2-oxobutanoate. Converts two cysteine molecules to lanthionine and hydrogen sulfide. Can also accept homocysteine as substrate. Specificity depends on the levels of the endogenous substrates. Generates the endogenous signaling molecule hydrogen sulfide (H2S), and so contributes to the regulation of blood pressure. Acts as a cysteine-protein sulfhydrase by mediating sulfhydration of target proteins: sulfhydration consists of converting -SH groups into -SSH on specific cysteine residues of target proteins such as GAPDH, PTPN1 and NF-kappa-B subunit RELA, thereby regulating their function.
Gene Name:
Uniprot ID:
Molecular weight:
L-Cystine + Water → Pyruvic acid + Ammonia + Thiocysteinedetails