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

## Contents

* 1 Catabolism
* 2 Atherosclerosis
* 3 Chronic infection
* 4 See also
* 5 References
* 6 External links

## Catabolism[edit | edit source]

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[edit | edit source]

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[edit | edit source]

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

## See also[edit | edit source]

## References[edit | edit source]

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. ↑ http://www.ncbi.nlm.nih.gov/pubmed/15640397
3. ↑ http://jama.ama-assn.org/content/274/13/1049.abstract
4. ↑ http://care.diabetesjournals.org/content/23/12/1816.abstract
5. ↑ http://www.medical-hypotheses.com/article/S0306-9877(09)00693-8/abstract
6. ↑ http://jama.ama-assn.org/content/279/5/392.extract

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* Anabolism/Quiz
* Anomeric carbons/Quiz
* Autocatalytic reactions/Quiz
* Autonomously replicating sequences/Quiz
* Base pairs/Quiz
* Biodegradation/Quiz
* Biosynthesis/Quiz
* Biosynthesis of a human protein/Quiz
* Biosynthesis of amino acids/Quiz
* Blood/Quiz
* Bodily fluids/Quiz
* Brain box/Quiz
* Calcium signaling/Quiz
* Capping enzymes/Quiz
* Carbohydrates/Quiz
* Catabolism/Quiz
* Catalysis/Quiz
* Cells/Quiz
* Cell signaling/Quiz
* Centrosomes/Quiz
* Chromatins/Quiz
* Chromoboxes/Quiz
* Coactivators/Quiz
* Corepressors/Quiz
* Cofactors/Quiz
* Consensus sequences/Quiz
* Control groups/Quiz
* Cytogenetics/Quiz
* Cytosine/Quiz
* Deoxyribonucleic acid/Quiz
* Digestion/Quiz
* Disaccharide/Quiz
* Downregulations/Quiz
* Endochondral ossification/Quiz
* Enzyme inhibitor/Quiz
* Enzymology/Quiz
* Epigenome/Quiz
* Esters/Quiz
* Esterification/Quiz
* Eukaryotes/Quiz
* Eukaryotic initiation factors/Quiz
* Evolution/Quiz
* Exaptation/Quiz
* Excision repair cross-complementing/Quiz
* Factors/Quiz
* Fatty acids/Quiz
* Ferredoxin/Quiz
* Foldings/Quiz
* Foods/Quiz
* Functional groups/Quiz
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* Genetics/Quiz
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* Genome surveillance complexes/Quiz
* Glycoproteins/Quiz
* Glycosides/Quiz
* Glycosidic bonds/Quiz
* Guanines/Quiz
* Helicases/Quiz
* Heredity/Quiz
* History of agriculture/Quiz
* Greek and Roman histories of biology/Quiz
* Homeoboxes/Quiz
* Homeostasis/Quiz
* Human amino acid synthesis/Quiz
* Human DNA/Quiz
* Human RNA/Quiz
* Human temperatures/Quiz
* Inhibitory peptides/Quiz
* Insulators/Quiz
* Intranuclear localizations/Quiz
* Introduction to Cell Biology/Quiz
* Introduction to polymer chemistry/Quiz
* Lamarckism/Quiz
* Localizations/Quiz
* Mathematical molecular biology/Quiz
* Mediator complexes/Quiz
* Melanocytes/Quiz
* Membranes/Quiz
* Molecular biology/Quiz
* Nitrogen metabolism/Quiz
* Nucleotide Synthesis/Quiz
* Origin of life/Quiz
* Post translational modification/Quiz
* Principles of biosynthesis/Quiz
* Proteins/Quiz
* Proteomics/Quiz
* Regulations/Quiz
* Ribonucleotides/Quiz
* Ribosomes/Quiz
* RNA polymerases/Quiz
* RNA polymerase II holoenzymes/Quiz
* RNA polymerase II holoenzyme complexes/Quiz
* RNA translations/Quiz
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* Metagenomes/Quiz
* Transport/Quiz
* Upregulations/Quiz
* Upstream and downstream/Quiz
* What is a human?/Quiz

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* A1BG
* AGC boxes
* Angiotensinogen core promoter element
* Boxes
* cAMP response elements
* B recognition elements
* CAAT boxes
* CArG boxes
* C and D boxes
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* V boxes
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* W boxes
* X boxes
* X core promoter element 1
* Y boxes
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Transcription quizzes|

* A1BG/Quiz
* AGC boxes/Quiz
* Angiotensinogen core promoter element/Quiz
* AP-1 box A and box B/Quiz
* Pre-initiation complex assembly/Quiz
* ATA box/Quiz
* Boxes/Quiz
* cAMP response elements/Quiz
* B recognition element/Quiz
* CAAT boxes/Quiz
* CArG boxes/Quiz
* C and D boxes/Quiz
* CENP-B boxes/Quiz
* CGCG boxes/Quiz
* Core promoter/Quiz
* CR elements/Quiz
* CRE boxes/Quiz
* Degenerate nucleotide/Quiz
* Dispersed promoters/Quiz
* Distal promoter/Quiz
* DNA melting/Quiz
* Downstream core element/Quiz
* Downstream promoter elements/Quiz
* Downstream TFIIB recognition elements/Quiz
* DREB boxes/Quiz
* E2 boxes/Quiz
* EIF4E basal element/Quiz
* Enhancers/Quiz
* F box/Quiz
* Focused promoters/Quiz
* Forkhead boxes/Quiz
* Fur boxes/Quiz
* GAAC elements/Quiz
* GAREs
* G boxes/Quiz
* GC boxes/Quiz
* Gene expressions/Quiz
* Gene promoter/Quiz
* General transcription factor/Quiz
* General transcription factor II As/Quiz
* General transcription factor II Bs/Quiz
* General transcription factor II D/Quiz
* General transcription factor II Fs/Quiz
* General transcription factor II Hs/Quiz
* Gene transcriptions/Quiz
* GLM boxes/Quiz
* H boxes/Quiz
* H and ACA boxes/Quiz
* HMG boxes/Quiz
* HNFs/Quiz
* HY boxes/Quiz
* I boxes/Quiz
* Initiator element/Quiz
* L boxes/Quiz
* M boxes/Quiz
* M35 boxes/Quiz
* MADS boxes/Quiz
* Metal responsive element/Quiz
* Motif ten element/Quiz
* MYB recognition elements/Quiz
* Nuclear factor of activated T cells (NFAT)/Quiz
* Nuclear factors/Quiz
* P boxes/Quiz
* Preinitiation complex/Quiz
* Pribnow box/Quiz
* Prolamin boxes/Quiz
* Promoters/Quiz
* Proximal promoter/Quiz
* Pyrimidine boxes/Quiz
* SAREs/Quiz
* Sp1s/Quiz
* STATs/Quiz
* TACTAAC boxes
* TATA binding protein/Quiz
* TATA binding protein associated factors/Quiz
* TATA boxes/Quiz
* TAT boxes/Quiz
* TATC boxes/Quiz
* T boxes/Quiz
* TCs/Quiz
* Transcriptional regulations/Quiz
* Transcription bubbles/Quiz
* Transcription factors quiz
* Transcription factories quiz
* Transcription of A1BG quiz
* Transcription start site quiz
* Upstream response elements quiz
* Upstream stimulating factors quiz
* V boxes quiz
* V and P boxes quiz
* W boxes quiz
* X boxes quiz
* X core promoter element 1 quiz
* Y boxes quiz
* Z boxes quiz

{{Medicine resources}}{{Phosphate biochemistry}}

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