Homocysteine

Homocysteine

Names
IUPAC name 2-Amino-4-sulfanylbutanoic acid
Identifiers
CAS Number	454-29-5 (racemate) Y 6027-13-0 (L-isomer) Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:17230 Y
ChEMBL	ChEMBL310604 Y
ChemSpider	757 Y
ECHA InfoCard	100.006.567
EC Number	207-222-9
KEGG	C05330 Y
PubChem	778
UNII	S7IJP4A89K (racemate) N 0LVT1QZ0BA (L-isomer) N
InChI InChI=1S/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7) Y Key: FFFHZYDWPBMWHY-UHFFFAOYSA-N Y InChI=1/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7) Key: FFFHZYDWPBMWHY-UHFFFAOYAS
SMILES C(CS)C(C(=O)O)N
Properties
Chemical formula	C4H9NO2S
Molar mass	135.18 g/mol
Appearance	White crystalline powder
Melting point	234–235 °C (453–455 °F; 507–508 K) (decomposes)
Solubility in water	soluble
log P	-2.56
Acidity (pKa)	2.25
Hazards
GHS pictograms
GHS signal word	Warning
GHS hazard statements	H302
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Homocysteine /ˌhoʊmoʊˈsɪstiːn/ is a non-protein α-amino acid. It is a homologue of the amino acid cysteine, differing by an additional methylene bridge (-CH₂-). It is biosynthesized from methionine by the removal of its terminal C^εmethyl group. Homocysteine can be recycled into methionine or converted into cysteine with the aid of certain B-vitamins.

A high level of homocysteine in the blood (hyperhomocysteinemia) makes a person more prone to endothelial cell injury, which leads to inflammation in the blood vessels, which in turn may lead to atherogenesis, which can result in ischemic injury. Hyperhomocysteinemia is therefore a possible risk factor for coronary artery disease. Coronary artery disease occurs when an atherosclerotic plaque blocks blood flow to the coronary arteries, which supply the heart with oxygenated blood.

Hyperhomocysteinemia has been correlated with the occurrence of blood clots, heart attacks and strokes, though it is unclear whether hyperhomocysteinemia is an independent risk factor for these conditions. Hyperhomoscyteinemia has also been associated with early pregnancy loss and with neural tube defects.