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|Section2= |Section7= }} Homocysteine 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 Cε methyl 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〔(Homocysteine and folate levels as risk factors for recurrent early pregnancy loss )〕 and with neural tube defects.〔van der Put NJ et al (Folate, Homocysteine and Neural Tube Defects: An Overview ) Exp Biol Med (Maywood) April 2001 vol. 226 no. 4 243-270〕 == Structure == Homocysteine exists at neutral pH values as a zwitterion. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Homocysteine」の詳細全文を読む スポンサード リンク
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