Homocysteine Metabolism
Homocysteine is a kind of amino acid found in the blood. It is a byproduct of the metabolic processes of the body, particularly of the methionine cycle. When this happens, the functions of the cardiovascular, nervous and skeletal systems are affected. Excess amounts of homocysteine in the body can lead to various health problems, such as heart disease. To lessen the amounts of this substance, the homocysteine needs to be metabolized. The metabolism of homocysteine undergoes two main pathways called remethylation and transsulfuration.
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Facts
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Homocysteine is created as a part of the methionine cycle. Methionine, an amino acid which is needed during metabolism, is converted to a substance called S-adenosylmethionine (SAMe). Homocysteine is produced when the SAMe loses a methyl group through the process of methylation. This is important because it regulates gene expression and the functioning of proteins. High levels of homocysteine are linked to certain health problems such as heart disease. In fact, the substance itself can cause damaged blood vessels at the cellular level.
Risks
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Homocysteine usually remains stored or is found in an inactive form. However, changes in the body's chemical levels can lead to the freeing of the homocysteine into the bloodstream. Excessively high levels of homocysteine in the blood leads to a higher occurrence of heart disease, stroke and other vascular illnesses. Its presence is also suspected of damaging the inner lining of the arteries and encouraging the formation of blood clots. However, long-term research is still needed to confirm this suspicion.
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Remethylation
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Homocysteine that is released into the blood can become methionine again. This is due to the presence of folic acid and vitamin B12. This process is called the remethylation pathway and is the primary reason for the elimination of the body's free homocysteine. There are some organs like the kidney and the liver that have the capability of remethylating the homocysteine back into SAMe on their own. However, they are only able to do this in small amounts.
Transsulfuration
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Excess homocysteine can lead to the creation of cysteine, which is then made into glutathione. Glutathione is a powerful antioxidant that promotes the health of the liver. The homocysteine's rate of transformation to glutathione increases when the body is under oxidative stress. This process is called transsulfuration because it results in the creation of sulfate byproducts, which are then excreted in the urine. Some necessary ingredients in transsulfuration are Vitamin B6 and folic acid. This helps promote the process of homocysteine metabolism.
Influences
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Homocysteine metabolism is influenced by diet and genetics. The most important nutrients in the metabolizing of homocysteine are vitamins B6, B12 and folic acid. These are important because they are responsible for breaking down the homocysteine found in the body. Aside from the dietary factors, the amount of homocysteine may be influenced by the inherent ability of the body to undergo methylation.
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