Homocysteine

Homocysteine is an uncommon amino acid. The molecular formula is HOO=CCH(NH₂)(CH₂)₂SH.

Catabolism

Homocysteine is produced by the hydrolysis of the common amino acid methionine.

Methionine + Water → Homocysteine + Methanol

Homocysteine can also be produced by the hydrolysis of S-adenosyl-L-homocysteine.

S-adenosyl-L-homocysteine + water ↔ adenosine + homocysteine

This reaction is catalyzed by the enzyme S-adenosyl-L-homocysteine hydrolase.^[1] This enzyme is involved in normal T-cell and macrophage function.^[2]

Atherosclerosis

Elevated levels of serum homocysteine is associated with an increased risk of coronary artery disease.^[3] Among individuals with type 2 diabetes elevated plasma homocysteine levels are associated with an increased risk of macroangiopathy and nephropathy.^[4] It is unclear if this increased risk is due to the homocysteine itself, the methanol which is produced as a by-product of homocysteine biosynthesis, or some other mechanism which is correlated with homocysteine biosynthesis. Some authors believe that methanol causes arteriosclerosis.^[5] Other authors believe that arteriosclerosis is caused by homocysteine via some direct but yet to be explained mechanism.^[6]

Chronic infection

Elevated serum homocysteine levels, in spite of normal dietary methionine intake, may therefore suggest a chronic infection.

References

↑ My very best wishes (9 July 2009). "S-adenosyl-L-homocysteine hydrolase, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2017-01-04. {{cite web}}: |author= has generic name (help)
↑ http://www.ncbi.nlm.nih.gov/pubmed/15640397
↑ http://jama.ama-assn.org/content/274/13/1049.abstract
↑ http://care.diabetesjournals.org/content/23/12/1816.abstract
↑ http://www.medical-hypotheses.com/article/S0306-9877(09)00693-8/abstract
↑ http://jama.ama-assn.org/content/279/5/392.extract

External links

[AdenosylHomocysteineHydrolase-1] My very best wishes (9 July 2009). "S-adenosyl-L-homocysteine hydrolase, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2017-01-04. {{cite web}}: |author= has generic name (help)

[2] ttp://www.ncbi.nlm.nih.gov/pubmed/15640397

[3] ttp://jama.ama-assn.org/content/274/13/1049.abstract

[4] ttp://care.diabetesjournals.org/content/23/12/1816.abstract

[5] ttp://www.medical-hypotheses.com/article/S0306-9877(09)00693-8/abstract

[6] ttp://jama.ama-assn.org/content/279/5/392.extract

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