Canmetcon
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Identification
YMDB IDYMDB00371
NameHomocysteine
SpeciesSaccharomyces cerevisiae
StrainBaker's yeast
DescriptionHomocysteine is a sulfur-containing amino acid that arises during methionine metabolism. Homocysteine can be recycled into methionine or converted into cysteine with the aid of B-vitamins.
Structure
Thumb
Synonyms
  • (+-)-homocysteine
  • (S)-2-amino-4-mercapto-Butanoate
  • (S)-2-amino-4-mercapto-Butanoic acid
  • 2-amino-4-mercapto-Butanoate
  • 2-amino-4-mercapto-Butanoic acid
  • 2-amino-4-mercapto-Butyric acid
  • 2-amino-4-mercapto-DL-Butyrate
  • 2-amino-4-mercapto-DL-Butyric acid
  • 2-Amino-4-mercaptobutyric acid
  • 2-amino-4-sulfanylbutanoate
  • 2-amino-4-sulfanylbutanoic acid
  • D,l-homocysteine
  • DL-2-amino-4-mercapto-Butyric acid
  • DL-2-Amino-4-mercaptobutyric acid
  • DL-Homocysteine
  • DL-homocysteine (free base)
  • HCY
  • Homo-CYS
  • homocysteine
  • L-2-amino-4-mercapto-Butyric acid
  • L-Homocysteine
  • Usaf B-12
  • 2-Amino-4-mercaptobutyrate
  • Homocysteine, L isomer
  • Homocysteine, L-isomer
  • 2 Amino 4 mercaptobutyric acid
  • L-Isomer homocysteine
CAS number454-29-5
WeightAverage: 135.185
Monoisotopic: 135.035399227
InChI KeyFFFHZYDWPBMWHY-UHFFFAOYSA-N
InChIInChI=1S/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7)
IUPAC Name2-amino-4-sulfanylbutanoic acid
Traditional IUPAC Namehomocysteine
Chemical FormulaC4H9NO2S
SMILES[H]OC(=O)C([H])(N([H])[H])C([H])([H])C([H])([H])S[H]
Chemical Taxonomy
Description belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon).
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentAlpha amino acids
Alternative Parents
Substituents
  • Alpha-amino acid
  • Thia fatty acid
  • Fatty acyl
  • Fatty acid
  • Amino acid
  • Alkylthiol
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Primary amine
  • Organosulfur compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic oxide
  • Primary aliphatic amine
  • Organopnictogen compound
  • Carbonyl group
  • Amine
  • Organic oxygen compound
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Physical Properties
StateSolid
Charge0
Melting point232-233 °C
Experimental Properties
PropertyValueReference
Water Solubility148 mg/mL [HMP experimental]PhysProp
LogPNot AvailablePhysProp
Predicted Properties
PropertyValueSource
Water Solubility14.8 g/LALOGPS
logP-2.3ALOGPS
logP-2.6ChemAxon
logS-0.96ALOGPS
pKa (Strongest Acidic)2.46ChemAxon
pKa (Strongest Basic)9.41ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count3ChemAxon
Polar Surface Area63.32 ŲChemAxon
Rotatable Bond Count3ChemAxon
Refractivity32.94 m³·mol⁻¹ChemAxon
Polarizability13.44 ųChemAxon
Number of Rings0ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular LocationsNot Available
Organoleptic PropertiesNot Available
SMPDB Pathways
Cysteine MetabolismPW002383 ThumbThumb?image type=greyscaleThumb?image type=simple
Methionine metabolism and salvagePW002384 ThumbThumb?image type=greyscaleThumb?image type=simple
One Carbon Pool by Folate IPW002468 ThumbThumb?image type=greyscaleThumb?image type=simple
Sulfur metabolismPW002483 ThumbThumb?image type=greyscaleThumb?image type=simple
KEGG Pathways
Sulfur metabolismec00920 Map00920
SMPDB Reactions
Acetylhomoserine + Hydrogen sulfideAcetic acid + hydron + Homocysteine
Homocysteine + Pyruvic acid + Ammoniumwater + L-Cystathionine
Homocysteine + L-Serinewater + L-Cystathionine
Homocysteine + 5-Methyltetrahydropteroyltri-L-glutamateL-Methionine + Tetrahydropteroyltri-L-glutamate
S-Adenosylhomocysteine + waterAdenosine + Homocysteine
KEGG ReactionsNot Available
Concentrations
Intracellular ConcentrationsNot Available
Extracellular ConcentrationsNot Available
Spectra
Spectra
References
References:
  • UniProt Consortium (2011). "Ongoing and future developments at the Universal Protein Resource." Nucleic Acids Res 39:D214-D219.21051339
  • Scheer, M., Grote, A., Chang, A., Schomburg, I., Munaretto, C., Rother, M., Sohngen, C., Stelzer, M., Thiele, J., Schomburg, D. (2011). "BRENDA, the enzyme information system in 2011." Nucleic Acids Res 39:D670-D676.21062828
Synthesis Reference:Karrenbauer, Michael; Kleemann, Axel; Luessling, Theodor; Schaefer, Fritz. D,L-Homocysteine (I). Ger. (1984), 4 pp.
External Links:
ResourceLink
CHEBI ID17230
HMDB IDHMDB00742
Pubchem Compound ID778
Kegg IDC05330
ChemSpider ID757
FOODB IDFDB001491
WikipediaHomocysteine
BioCyc IDHOMO-CYS

Enzymes

General function:
Involved in pyridoxal phosphate binding
Specific function:
Transforms O-acetylhomoserine into homocysteine and O- acetylserine into cysteine
Gene Name:
MET17
Uniprot ID:
P06106
Molecular weight:
48671.39844
Reactions
O-acetyl-L-homoserine + methanethiol → L-methionine + acetate.
O(3)-acetyl-L-serine + H(2)S → L-cysteine + acetate.
General function:
Involved in adenosylhomocysteinase activity
Specific function:
Adenosylhomocysteine is a competitive inhibitor of S- adenosyl-L-methionine-dependent methyl transferase reactions; therefore adenosylhomocysteinase may play a key role in the control of methylations via regulation of the intracellular concentration of adenosylhomocysteine
Gene Name:
SAH1
Uniprot ID:
P39954
Molecular weight:
49125.10156
Reactions
S-adenosyl-L-homocysteine + H(2)O → L-homocysteine + adenosine.
General function:
Involved in 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase activity
Specific function:
Catalyzes the transfer of a methyl group from 5- methyltetrahydrofolate to homocysteine resulting in methionine formation
Gene Name:
MET6
Uniprot ID:
P05694
Molecular weight:
85859.20313
Reactions
5-methyltetrahydropteroyltri-L-glutamate + L-homocysteine → tetrahydropteroyltri-L-glutamate + L-methionine.
General function:
Involved in pyridoxal phosphate binding
Specific function:
L-cystathionine + H(2)O = L-homocysteine + NH(3) + pyruvate
Gene Name:
STR3
Uniprot ID:
P53101
Molecular weight:
51828.0
Reactions
L-cystathionine + H(2)O → L-homocysteine + NH(3) + pyruvate.
General function:
Involved in pyridoxal phosphate binding
Specific function:
L-cystathionine + H(2)O = L-homocysteine + NH(3) + pyruvate
Gene Name:
IRC7
Uniprot ID:
P43623
Molecular weight:
36971.10156
Reactions
L-cystathionine + H(2)O → L-homocysteine + NH(3) + pyruvate.
General function:
Involved in cysteine biosynthetic process from serine
Specific function:
L-serine + L-homocysteine = L-cystathionine + H(2)O
Gene Name:
CYS4
Uniprot ID:
P32582
Molecular weight:
56021.30078
Reactions
L-serine + L-homocysteine → L-cystathionine + H(2)O.
General function:
Involved in homocysteine S-methyltransferase activity
Specific function:
Homocysteine S-methyltransferase involved in the conversion of S-adenosylmethionine (AdoMet) to methionine to control the methionine/AdoMet ratio. Converts also S- methylmethionine (SMM) to methionine
Gene Name:
MHT1
Uniprot ID:
Q12525
Molecular weight:
36714.5
Reactions
S-methyl-L-methionine + L-homocysteine → 2 L-methionine.
General function:
Involved in homocysteine S-methyltransferase activity
Specific function:
Homocysteine S-methyltransferase involved in the conversion of S-adenosylmethionine (AdoMet) to methionine to control the methionine/AdoMet ratio. Converts also S- methylmethionine (SMM) to methionine
Gene Name:
SAM4
Uniprot ID:
Q08985
Molecular weight:
36668.19922
Reactions
S-methyl-L-methionine + L-homocysteine → 2 L-methionine.