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Homocysteine, an amino acid with the formula HSCH2CH2CH(NH2)CO2H, is a homologue of the amino acid cysteine, differing from it only by an additional methylene (-CH2-) group. It is biosynthesized from methionine by the removal of its terminal Cε methyl group. Homocysteine can be recycled into methionine or converted into cysteine with B-vitamins. Copyright Text is available under the Creative Commons Attribution/Share-Alike License. See for details. Source: Wikipedia, Homocystine

Homocysteine is a sulfur-containing amino acid that arises during methionine metabolism. Although its concentration in plasma is only about 10 micromolar (uM), even moderate hyperhomocysteinemia is associated with increased incidence of cardiovascular disease and Alzheimer's disease. Elevations in plasma homocysteine are commonly found as a result of vitamin deficiencies, polymorphisms of enzymes of methionine metabolism, and renal disease. Pyridoxal, folic acid, riboflavin, and Vitamin B(12) are all required for methionine metabolism, and deficiency of each of these vitamins result in elevated plasma homocysteine. A polymorphism of methylenetetrahydrofolate reductase (C677T), which is quite common in most populations with a homozygosity rate of 10-15 %, is associated with moderate hyperhomocysteinemia, especially in the context of marginal folate intake. Plasma homocysteine is inversely related to plasma creatinine in patients with renal disease. This is due to an impairment in homocysteine removal in renal disease. The role of these factors, and of modifiable lifestyle factors, in affecting methionine metabolism and in determining plasma homocysteine levels is discussed. Homocysteine is an independent cardiovascular disease (CVD) risk factor modifiable by nutrition and possibly exercise. Homocysteine was first identified as an important biological compound in 1932 and linked with human disease in 1962 when elevated urinary homocysteine levels were found in children with mental retardation. This condition, called homocysteinuria, was later associated with premature occlusive CVD, even in children. These observations led to research investigating the relationship of elevated homocysteine levels and CVD in a wide variety of populations including middle age and elderly men and women with and without traditional risk factors for CVD. PMID: 17136938, PMID: 15630149 Copyright Copyright ©2005-2009 Genome Alberta (Reference to original publication: Wishart DS, Knox C, Guo AC, et al. HMDB: a knowledgebase for the human metabolome. Nucleic Acids Res. 2009 37(Database issue):D603-610.) Source: Human Metabolome Database, Homocysteine

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Tag Language Translation
zh-CN Chinese (China) 同型半胱氨酸
Synonyms: HCY;Hcys;Hcyst;巯基丁氨酸;高半胱氨酸
fr-CA French (Canada) Homocystéine
et-EE Estonian (Estonia) Homotsüsteiin
es-ES Spanish (Spain) Homocisteína
it-IT Italian (Italy) Omocisteina
el-GR Greek (Greece) Ομοκυστεΐνη
tr-TR Turkish (Turkey) Homosistein
ru-RU Russian (Russian Federation) Гомоцистеин
nl-NL Dutch (Netherlands) homocysteïne
fr-BE French (Belgium) Homocystéine