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Identification
YMDB IDYMDB00520
NameL-Homocysteine
SpeciesSaccharomyces cerevisiae
StrainBaker's yeast
DescriptionL-Homocysteine, also known as Hcy, belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. L-Homocysteine is a very strong basic compound (based on its pKa). L-Homocysteine exists in both E. coli (prokaryote) and yeast (eukaryote).
Structure
Thumb
Synonyms
  • (S)-2-amino-4-mercapto-butanoic acid
  • 2-amino-4-mercapto-butanoic acid
  • 2-amino-4-mercapto-butyric acid
  • 2-Amino-4-mercaptobutyric acid
  • Hcy
  • Homocysteine
  • l-2-amino-4-mercaptobutyric acid
  • L-homocysteine
  • L-2-Amino-4-mercaptobutyrate
  • Homocysteine, L isomer
  • L-Isomer homocysteine
  • 2 amino 4 Mercaptobutyric acid
  • Homocysteine, L-isomer
  • (S)-2-Amino-4-mercapto-butanoate
  • (S)-2-Amino-4-mercaptobutanoic acid
  • (S)-Homocysteine
  • 2-Amino-4-mercapto-DL-butyrate
  • 2-Amino-4-mercapto-DL-butyric acid
  • 2-Amino-4-mercapto-L-butyric acid
  • 2-Amino-4-mercapto-butanoate
  • 2-Amino-4-mercapto-butyric 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
  • Homo-Cys
  • L-2-Amino-4-mercapto-butyric acid
CAS number6027-13-0
WeightAverage: 135.185
Monoisotopic: 135.035399227
InChI KeyFFFHZYDWPBMWHY-VKHMYHEASA-N
InChIInChI=1S/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7)/t3-/m0/s1
IUPAC Name(2S)-2-amino-4-sulfanylbutanoic acid
Traditional IUPAC NameL-homocysteine
Chemical FormulaC4H9NO2S
SMILESN[C@@H](CCS)C(O)=O
Chemical Taxonomy
Description belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentL-alpha-amino acids
Alternative Parents
Substituents
  • L-alpha-amino acid
  • Thia fatty acid
  • Fatty acid
  • Fatty acyl
  • Amino acid
  • Alkylthiol
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • 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 Descriptors
Physical Properties
StateSolid
Charge0
Melting point232.5 °C
Experimental Properties
PropertyValueReference
Water SolubilityNot AvailablePhysProp
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
Refractivity32.93 m³·mol⁻¹ChemAxon
Polarizability13.54 ųChemAxon
Number of Rings0ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular Locations
  • peroxisome
  • cytoplasm
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
Cysteine and methionine metabolismec00270 Map00270
Sulfur metabolismec00920 Map00920
SMPDB ReactionsNot Available
KEGG Reactions
L-Homocysteine + 5-Methyltetrahydropteroyltri-L-glutamic acidL-Methionine + Tetrahydropteroyltri-L-glutamate
S-Adenosylhomocysteine + waterAdenosine + L-Homocysteine
L-Cystathionine + waterL-Homocysteine + Pyruvic acid + Ammonium
L-Homocysteine + L-SerineL-Cystathionine + water
L-Homocysteine + S-AdenosylmethionineL-Methionine + S-Adenosylhomocysteine + hydron
Concentrations
Intracellular ConcentrationsNot Available
Extracellular ConcentrationsNot Available
Spectra
Spectra
References
References:
  • 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
  • Herrgard, M. J., Swainston, N., Dobson, P., Dunn, W. B., Arga, K. Y., Arvas, M., Bluthgen, N., Borger, S., Costenoble, R., Heinemann, M., Hucka, M., Le Novere, N., Li, P., Liebermeister, W., Mo, M. L., Oliveira, A. P., Petranovic, D., Pettifer, S., Simeonidis, E., Smallbone, K., Spasic, I., Weichart, D., Brent, R., Broomhead, D. S., Westerhoff, H. V., Kirdar, B., Penttila, M., Klipp, E., Palsson, B. O., Sauer, U., Oliver, S. G., Mendes, P., Nielsen, J., Kell, D. B. (2008). "A consensus yeast metabolic network reconstruction obtained from a community approach to systems biology." Nat Biotechnol 26:1155-1160.18846089
  • Mulet, J. M., Alemany, B., Ros, R., Calvete, J. J., Serrano, R. (2004). "Expression of a plant serine O-acetyltransferase in Saccharomyces cerevisiae confers osmotic tolerance and creates an alternative pathway for cysteine biosynthesis." Yeast 21:303-312.15042590
  • Jhee, K. H., McPhie, P., Miles, E. W. (2000). "Yeast cystathionine beta-synthase is a pyridoxal phosphate enzyme but, unlike the human enzyme, is not a heme protein." J Biol Chem 275:11541-11544.10766767
  • Suliman, H. S., Sawyer, G. M., Appling, D. R., Robertus, J. D. (2005). "Purification and properties of cobalamin-independent methionine synthase from Candida albicans and Saccharomyces cerevisiae." Arch Biochem Biophys 441:56-63.16083849
  • Thomas, D., Becker, A., Surdin-Kerjan, Y. (2000). "Reverse methionine biosynthesis from S-adenosylmethionine in eukaryotic cells." J Biol Chem 275:40718-40724.11013242
  • Tehlivets, O., Hasslacher, M., Kohlwein, S. D. (2004). "S-adenosyl-L-homocysteine hydrolase in yeast: key enzyme of methylation metabolism and coordinated regulation with phospholipid synthesis." FEBS Lett 577:501-506.15556636
  • Csaikl, U., Csaikl, F. (1986). "Molecular cloning and characterization of the MET6 gene of Saccharomyces cerevisiae." Gene 46:207-214.3542720
Synthesis Reference:Not Available
External Links:
ResourceLink
CHEBI ID17588
HMDB IDNot Available
Pubchem Compound ID91552
Kegg IDC00155
ChemSpider ID82666
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.