Human Metabolome Database Version 3.5

Showing metabocard for Homocysteine (HMDB00742)

Record Information
Version 3.5
Creation Date 2005-11-16 08:48:42 -0700
Update Date 2013-05-29 13:28:52 -0600
HMDB ID HMDB00742
Secondary Accession Numbers
  • HMDB00165
Metabolite Identification
Common Name Homocysteine
Description 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 Link_out, 15630149 Link_out).
Structure Thumb
Download: MOL | SDF | PDB | SMILES | InChI
Display: 2D Structure | 3D Structure
Synonyms
  1. (+-)-homocysteine
  2. (S)-2-amino-4-mercapto-Butanoate
  3. (S)-2-amino-4-mercapto-Butanoic acid
  4. 2-Amino-4-mercapto-Butanoate
  5. 2-Amino-4-mercapto-Butanoic acid
  6. 2-Amino-4-mercapto-Butyric acid
  7. 2-Amino-4-mercapto-DL-Butyrate
  8. 2-Amino-4-mercapto-DL-Butyric acid
  9. 2-Amino-4-mercaptobutyric acid
  10. 2-Amino-4-sulfanylbutanoate
  11. 2-Amino-4-sulfanylbutanoic acid
  12. D,L-Homocysteine
  13. DL-2-amino-4-mercapto-Butyric acid
  14. DL-2-Amino-4-mercaptobutyric acid
  15. DL-Homocysteine
  16. DL-homocysteine (free base)
  17. HCY
  18. Homo-CYS
  19. Homocysteine
  20. L-2-Amino-4-mercapto-Butyric acid
  21. L-Homocysteine
  22. Usaf B-12
Chemical Formula C4H9NO2S
Average Molecular Weight 135.185
Monoisotopic Molecular Weight 135.035399227
IUPAC Name 2-amino-4-sulfanylbutanoic acid
Traditional IUPAC Name homocysteine
CAS Registry Number 454-29-5
SMILES NC(CCS)C(O)=O
InChI Identifier InChI=1S/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7)
InChI Key FFFHZYDWPBMWHY-UHFFFAOYSA-N
Chemical Taxonomy
Kingdom Organic Compounds
Super Class Amino Acids, Peptides, and Analogues
Class Amino Acids and Derivatives
Sub Class Alpha Amino Acids and Derivatives
Other Descriptors
  • Aliphatic Acyclic Compounds
  • amino acid zwitterion(ChEBI)
Substituents
  • Alkylthiol
  • Carboxylic Acid
  • Primary Aliphatic Amine (Alkylamine)
  • Thiol (Sulfanyl Compound)
Direct Parent Alpha Amino Acids and Derivatives
Ontology
Status Detected and Quantified
Origin
  • Drug metabolite
  • Endogenous
Biofunction
  • Component of Glycine, serine and threonine metabolism
  • Component of Methionine metabolism
  • Component of Selenoamino acid metabolism
  • Component of Ubiquinone biosynthesis
  • Essential amino acid
  • Waste products
Application Not Available
Cellular locations
  • Cytoplasm (predicted from logP)
Physical Properties
State Solid
Experimental Properties
Property Value Reference
Melting Point 232 - 233 °C Not Available
Boiling Point Not Available Not Available
Water Solubility 148 mg/mL Not Available
LogP Not Available Not Available
Predicted Properties
Property Value Source
Water Solubility 14.8 g/L ALOGPS
LogP -2.29 ALOGPS
LogP -2.6 ChemAxon
LogS -0.96 ALOGPS
pKa (strongest acidic) 2.46 ChemAxon
pKa (strongest basic) 9.41 ChemAxon
Hydrogen Acceptor Count 3 ChemAxon
Hydrogen Donor Count 3 ChemAxon
Polar Surface Area 63.32 A2 ChemAxon
Rotatable Bond Count 3 ChemAxon
Refractivity 32.94 ChemAxon
Polarizability 13.44 ChemAxon
Formal Charge 0 ChemAxon
Physiological Charge 0 ChemAxon
Spectra
Gas-MS Spectrum
1H NMR Spectrum
MS/MS Spectrum Quattro_QQQ 10
MS/MS Spectrum Quattro_QQQ 25
MS/MS Spectrum Quattro_QQQ 40
MS/MS Spectrum GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies )
MS/MS Spectrum GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies )
MS/MS Spectrum GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies )
MS/MS Spectrum GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies)
MS/MS Spectrum GC-MS
MS/MS Spectrum GC-MS
[1H,13C] 2D NMR Spectrum
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biofluid Locations
  • Blood
  • Cerebrospinal Fluid (CSF)
  • Urine
Tissue Location
  • Muscle
  • Fibroblasts
  • Intestine
  • Neuron
  • Pancreas
  • Placenta
  • Kidney
  • Liver
  • Brain
  • Adipose Tissue
  • Nerve Cells
  • Platelet
  • Artery
Pathways
Name SMPDB Link KEGG Link
Methionine Metabolism SMP00033 map00270 Link_out
Glycine and Serine Metabolism SMP00004 map00260 Link_out
Betaine Metabolism SMP00123 map00260 Link_out
Homocysteine Degradation SMP00455 Not Available
Catecholamine Biosynthesis SMP00012 map00350 Link_out
Normal Concentrations
Biofluid Status Value Age Sex Condition Reference
Blood Detected and Quantified
9.4 (7.3-16.2) uM Adult (>18 years old) Not Specified Normal
Blood Detected and Quantified
9.8 (7.6-14.9) uM Adult (>18 years old) Both Normal
Blood Detected and Quantified
5.00 +/- 1.6 uM Infant (0-1 year old) Both Normal
Blood Detected and Quantified
10.4 +/- 2.3 uM Children (1-13 year old) Both Normal
Blood Detected and Quantified
9.00 +/- 2.2 uM Adolescent (13-18 years old) Both Normal
Blood Detected and Quantified
9.00 +/- 2.00 uM Adult (>18 years old) Both Normal
Blood Detected and Quantified
6.00 (4.8-7.40) uM Adult (>18 years old) Both Normal
Blood Detected and Quantified
9.11 +/- 2.99 uM Adult (>18 years old) Not Specified Normal
Cerebrospinal Fluid (CSF) Detected and Quantified
0.09 (0.06-0.16) uM Adult (>18 years old) Not Specified Normal
Cerebrospinal Fluid (CSF) Detected and Quantified
20.7 +/- 1.7 uM Elderly (>65 years old) Both Normal
Cerebrospinal Fluid (CSF) Detected and Quantified
0.057 +/- 0.035 uM Adult (>18 years old) Not Specified Normal
Cerebrospinal Fluid (CSF) Detected and Quantified
0.12 +/- 0.08 uM Elderly (>65 years old) Not Specified Normal
Cerebrospinal Fluid (CSF) Detected and Quantified
0.15 +/- 0.07 uM Adult (>18 years old) Not Specified Normal
Urine Detected and Quantified
1.1 (0.6-1.74) umol/mmol creatinine Adult (>18 years old) Both Comment Normal
Urine Detected and Quantified
2.00 +/- 1.65 umol/mmol creatinine Infant (0-1 year old) Male Normal
Urine Detected and Quantified
1.5 +/- 0.69 umol/mmol creatinine Children (1-13 year old) Male Normal
Urine Detected and Quantified
1.78 +/- 0.73 umol/mmol creatinine Adolescent (13-18 years old) Male Normal
Urine Detected and Quantified
1.95 +/- 1.47 umol/mmol creatinine Adult (>18 years old) Male Normal
Abnormal Concentrations
Biofluid Status Value Age Sex Condition Reference
Blood Detected and Quantified 12.9 (8.2-28.2) uM Adult (>18 years old) Not Specified Dementia (Alzheimer's and non-Alzheimer's)
Blood Detected and Quantified 10.7 (7.6-14.4) uM Adult (>18 years old) Not Specified Multiple sclerosis
Blood Detected and Quantified 10.2 (7.0-17.4) uM Adult (>18 years old) Not Specified Stroke
Blood Detected and Quantified 11.9 (7.0-19.1) uM Adult (>18 years old) Not Specified Peripheral neuropathy
Blood Detected and Quantified 21.0 (18.5-25.7) uM Adult (>18 years old) Both Chronic renal failure
Blood Detected and Quantified 25.5 (16.9-32.6) uM Adult (>18 years old) Both Continuous ambulatory peritoneal dialysis (CAPD)
Blood Detected and Quantified 29.7 (25.7-38.2) uM Adult (>18 years old) Both Hemodialysis
Blood Detected and Quantified 12.5 +/- 5.0 uM Adult (>18 years old) Both Comment Sickle cell anemia
Blood Detected and Quantified 125.00 (50.00-200.00) uM Children (1-13 year old) Both Cystathionine beta-synthase deficiency
Blood Detected and Quantified 9.22 +/- 1.81 uM Adult (>18 years old) Not Specified Cruetzfeldt-Jakob disease
Blood Detected and Quantified 15.1 uM Adult (>18 years old) Both Parkinson's disease
Blood Detected and Quantified 13.94 +/- 3.47 uM Adult (>18 years old) Both Amyotrophic lateral sclerosis
Blood Detected and Quantified 15.75 +/- 5.75 uM Adult (>18 years old) Both Progressive supranuclear palsy
Cerebrospinal Fluid (CSF) Detected and Quantified 0.08 (0.05-0.16) uM Adult (>18 years old) Not Specified Multiple sclerosis
Cerebrospinal Fluid (CSF) Detected and Quantified 0.08 (0.06-0.15) uM Adult (>18 years old) Not Specified Stroke
Cerebrospinal Fluid (CSF) Detected and Quantified 0.11 (0.07-0.18) uM Adult (>18 years old) Not Specified Peripheral neuropathy
Cerebrospinal Fluid (CSF) Detected and Quantified 0.216 +/- 0.122 uM Adult (>18 years old) Not Specified Alzheimer's disease
Cerebrospinal Fluid (CSF) Detected and Quantified 0.12 +/- 0.062 uM Elderly (>65 years old) Not Specified Alzheimer's disease
Cerebrospinal Fluid (CSF) Detected and Quantified 0.10 (0.06–0.32) uM Adult (>18 years old) Not Specified Dementia (Alzheimer's and non-Alzheimer's)
Cerebrospinal Fluid (CSF) Detected and Quantified 14.2 +/- 1.7 uM Elderly (>65 years old) Not Specified Alzheimer's disease
Cerebrospinal Fluid (CSF) Detected and Quantified 0.13 +/- 0.03 uM Adult (>18 years old) Not Specified Cruetzfeldt-Jakob disease
Associated Disorders and Diseases
Disease References
Creutzfeldt-Jakob disease
  • Bleich S, Otto M, Zerr I, Kropp S, Kretzschmar HA, Wiltfang J: Creutzfeldt-Jakob disease and homocysteine levels in plasma and cerebrospinal fluid. Gerontology. 2005 Mar-Apr;51(2):142-4. Pubmed: 15711082 Link_out
  • [No authors listed] Pubmed: 115711082 Link_out
      Dementia
      • Obeid R, Kasoha M, Knapp JP, Kostopoulos P, Becker G, Fassbender K, Herrmann W: Folate and methylation status in relation to phosphorylated tau protein(181P) and beta-amyloid(1-42) in cerebrospinal fluid. Clin Chem. 2007 Jun;53(6):1129-36. Epub 2007 Mar 23. Pubmed: 17384003 Link_out
          Alzheimer's disease
          • Selley ML, Close DR, Stern SE: The effect of increased concentrations of homocysteine on the concentration of (E)-4-hydroxy-2-nonenal in the plasma and cerebrospinal fluid of patients with Alzheimer's disease. Neurobiol Aging. 2002 May-Jun;23(3):383-8. Pubmed: 11959400 Link_out
          • Serot JM, Barbe F, Arning E, Bottiglieri T, Franck P, Montagne P, Nicolas JP: Homocysteine and methylmalonic acid concentrations in cerebrospinal fluid: relation with age and Alzheimer's disease. J Neurol Neurosurg Psychiatry. 2005 Nov;76(11):1585-7. Pubmed: 16227558 Link_out
              Sickle cell anemia
              • van der Dijs FP, Schnog JJ, Brouwer DA, Velvis HJ, van den Berg GA, Bakker AJ, Duits AJ, Muskiet FD, Muskiet FA: Elevated homocysteine levels indicate suboptimal folate status in pediatric sickle cell patients. Am J Hematol. 1998 Nov;59(3):192-8. Pubmed: 9798656 Link_out
                  Multiple sclerosis
                  • Obeid R, Kasoha M, Knapp JP, Kostopoulos P, Becker G, Fassbender K, Herrmann W: Folate and methylation status in relation to phosphorylated tau protein(181P) and beta-amyloid(1-42) in cerebrospinal fluid. Clin Chem. 2007 Jun;53(6):1129-36. Epub 2007 Mar 23. Pubmed: 17384003 Link_out
                      Stroke
                      • Obeid R, Kasoha M, Knapp JP, Kostopoulos P, Becker G, Fassbender K, Herrmann W: Folate and methylation status in relation to phosphorylated tau protein(181P) and beta-amyloid(1-42) in cerebrospinal fluid. Clin Chem. 2007 Jun;53(6):1129-36. Epub 2007 Mar 23. Pubmed: 17384003 Link_out
                          Peripheral neuropathy
                          • Obeid R, Kasoha M, Knapp JP, Kostopoulos P, Becker G, Fassbender K, Herrmann W: Folate and methylation status in relation to phosphorylated tau protein(181P) and beta-amyloid(1-42) in cerebrospinal fluid. Clin Chem. 2007 Jun;53(6):1129-36. Epub 2007 Mar 23. Pubmed: 17384003 Link_out
                              Chronic renal failure
                              • McGregor DO, Dellow WJ, Lever M, George PM, Robson RA, Chambers ST: Dimethylglycine accumulates in uremia and predicts elevated plasma homocysteine concentrations. Kidney Int. 2001 Jun;59(6):2267-72. Pubmed: 11380830 Link_out
                                  Continuous ambulatory peritoneal dialysis
                                  • McGregor DO, Dellow WJ, Lever M, George PM, Robson RA, Chambers ST: Dimethylglycine accumulates in uremia and predicts elevated plasma homocysteine concentrations. Kidney Int. 2001 Jun;59(6):2267-72. Pubmed: 11380830 Link_out
                                      Hemodialysis
                                      • McGregor DO, Dellow WJ, Lever M, George PM, Robson RA, Chambers ST: Dimethylglycine accumulates in uremia and predicts elevated plasma homocysteine concentrations. Kidney Int. 2001 Jun;59(6):2267-72. Pubmed: 11380830 Link_out
                                          Homocystinuria
                                              Parkinson's disease
                                              • Levin J, Botzel K, Giese A, Vogeser M, Lorenzl S: Elevated levels of methylmalonate and homocysteine in Parkinson's disease, progressive supranuclear palsy and amyotrophic lateral sclerosis. Dement Geriatr Cogn Disord. 2010 Jul;29(6):553-9. Epub 2010 Jul 3. Pubmed: 20606437 Link_out
                                                  Associated OMIM IDs
                                                  DrugBank ID Not Available
                                                  DrugBank Metabolite ID DBMET00508 Link_out
                                                  Phenol Explorer Compound ID Not Available
                                                  Phenol Explorer Metabolite ID Not Available
                                                  FoodDB ID FDB001491
                                                  KNApSAcK ID C00001365 Link_out
                                                  Chemspider ID 757 Link_out
                                                  KEGG Compound ID Not Available
                                                  BioCyc ID HOMO-CYS Link_out
                                                  BiGG ID 45588 Link_out
                                                  Wikipedia Link Homocysteine Link_out
                                                  NuGOwiki Link HMDB00742 Link_out
                                                  Metagene Link HMDB00742 Link_out
                                                  METLIN ID 3256 Link_out
                                                  PubChem Compound 778 Link_out
                                                  PDB ID Not Available
                                                  ChEBI ID 17230 Link_out
                                                  References
                                                  Synthesis Reference Karrenbauer, Michael; Kleemann, Axel; Luessling, Theodor; Schaefer, Fritz. D,L-Homocysteine (I). Ger. (1984), 4 pp.
                                                  Material Safety Data Sheet (MSDS) Download (PDF)
                                                  General References
                                                  1. Yu CK, Lakasing L, Papageorghiou AT, Spencer K, Nicolaides KH: Uterine artery Doppler and mid-trimester maternal plasma homocysteine in subsequent pre-eclampsia. J Matern Fetal Neonatal Med. 2004 Aug;16(2):134-9. Pubmed: 15512726 Link_out
                                                  2. Giladi N, Mordechovich M, Gruendlinger L, Shabtai H, Merims D, Naor S, Baltadzhieva R, Hausdorff JM, Gur AY, Bornstein NM: "Brain Screen": A self-referral, screening program for strokes, falls and dementia risk factors. J Neurol. 2006 Mar;253(3):307-15. Epub 2005 Oct 10. Pubmed: 16208527 Link_out
                                                  3. Terzolo M, Allasino B, Bosio S, Brusa E, Daffara F, Ventura M, Aroasio E, Sacchetto G, Reimondo G, Angeli A, Camaschella C: Hyperhomocysteinemia in patients with Cushing's syndrome. J Clin Endocrinol Metab. 2004 Aug;89(8):3745-51. Pubmed: 15292300 Link_out
                                                  4. Laxdal E, Eide GE, Amundsen SR, Dregelid EB, Pedersen G, Jonung T, Aune S: Homocysteine levels, haemostatic risk factors and restenosis after carotid thrombendarterectomy. Eur J Vasc Endovasc Surg. 2004 Sep;28(3):323-8. Pubmed: 15288638 Link_out
                                                  5. Akoglu B, Wondra K, Caspary WF, Faust D: Determinants of fasting total serum homocysteine levels in liver transplant recipients. Exp Clin Transplant. 2006 Jun;4(1):462-6. Pubmed: 16827644 Link_out
                                                  6. Krantz JS, Mack WJ, Hodis HN, Liu CR, Liu CH, Kaufman FR: Early onset of subclinical atherosclerosis in young persons with type 1 diabetes. J Pediatr. 2004 Oct;145(4):452-7. Pubmed: 15480366 Link_out
                                                  7. Selley ML, Close DR, Stern SE: The effect of increased concentrations of homocysteine on the concentration of (E)-4-hydroxy-2-nonenal in the plasma and cerebrospinal fluid of patients with Alzheimer's disease. Neurobiol Aging. 2002 May-Jun;23(3):383-8. Pubmed: 11959400 Link_out
                                                  8. Serot JM, Barbe F, Arning E, Bottiglieri T, Franck P, Montagne P, Nicolas JP: Homocysteine and methylmalonic acid concentrations in cerebrospinal fluid: relation with age and Alzheimer's disease. J Neurol Neurosurg Psychiatry. 2005 Nov;76(11):1585-7. Pubmed: 16227558 Link_out
                                                  9. Hershcovici T, Schechner V, Orlin J, Harell D, Beigel Y: Effect of different LDL-apheresis methods on parameters involved in atherosclerosis. J Clin Apher. 2004;19(2):90-7. Pubmed: 15274202 Link_out
                                                  10. Muller T, Renger K, Kuhn W: Levodopa-associated increase of homocysteine levels and sural axonal neurodegeneration. Arch Neurol. 2004 May;61(5):657-60. Pubmed: 15148140 Link_out
                                                  11. Eskes TK: Homocysteine and human reproduction. Clin Exp Obstet Gynecol. 2000;27(3-4):157-67. Pubmed: 11214939 Link_out
                                                  12. Winkelmayer WC, Kramar R, Curhan GC, Chandraker A, Endler G, Fodinger M, Horl WH, Sunder-Plassmann G: Fasting plasma total homocysteine levels and mortality and allograft loss in kidney transplant recipients: a prospective study. J Am Soc Nephrol. 2005 Jan;16(1):255-60. Epub 2004 Nov 24. Pubmed: 15563562 Link_out
                                                  13. Park BH, Kim YJ, Park JS, Lee HY, Ha EH, Min JW, Park HS: [Folate and homocysteine levels during pregnancy affect DNA methylation in human placenta] J Prev Med Pub Health. 2005 Nov;38(4):437-42. Pubmed: 16358830 Link_out
                                                  14. Hossain GS, van Thienen JV, Werstuck GH, Zhou J, Sood SK, Dickhout JG, de Koning AB, Tang D, Wu D, Falk E, Poddar R, Jacobsen DW, Zhang K, Kaufman RJ, Austin RC: TDAG51 is induced by homocysteine, promotes detachment-mediated programmed cell death, and contributes to the cevelopment of atherosclerosis in hyperhomocysteinemia. J Biol Chem. 2003 Aug 8;278(32):30317-27. Epub 2003 May 8. Pubmed: 12738777 Link_out
                                                  15. Schafer SA, Mussig K, Stefan N, Haring HU, Fritsche A, Balletshofer BM: Plasma homocysteine concentrations in young individuals at increased risk of type 2 diabetes are associated with subtle differences in glomerular filtration rate but not with insulin resistance. Exp Clin Endocrinol Diabetes. 2006 Jun;114(6):306-9. Pubmed: 16868889 Link_out
                                                  16. Tchantchou F: Homocysteine increase folate oxidative brain homocysteine metabolism and various consequences of folate deficiency. J Alzheimers Dis. 2006 Aug;9(4):421-7. Pubmed: 16917151 Link_out
                                                  17. Siroka R, Trefil L, Rajdl D, Racek J, Rusnakova H, Cibulka R, Eiselt J, Filipovsky J: Asymmetric dimethylarginine, homocysteine and renal function--is there a relation? Clin Chem Lab Med. 2005;43(10):1147-50. Pubmed: 16197312 Link_out
                                                  18. Onalan R, Onalan G, Gunenc Z, Karabulut E: Combining 2nd-trimester maternal serum homocysteine levels and uterine artery Doppler for prediction of preeclampsia and isolated intrauterine growth restriction. Gynecol Obstet Invest. 2006;61(3):142-8. Epub 2005 Dec 20. Pubmed: 16374017 Link_out
                                                  19. Robinson G, Narasimhan S, Weatherall M, Beasley R: Raised plasma homocysteine levels in alcoholism: increasing the risk of heart disease and dementia? N Z Med J. 2005 Jun 3;118(1216):U1490. Pubmed: 15937525 Link_out
                                                  20. Gulsen M, Yesilova Z, Bagci S, Uygun A, Ozcan A, Ercin CN, Erdil A, Sanisoglu SY, Cakir E, Ates Y, Erbil MK, Karaeren N, Dagalp K: Elevated plasma homocysteine concentrations as a predictor of steatohepatitis in patients with non-alcoholic fatty liver disease. J Gastroenterol Hepatol. 2005 Sep;20(9):1448-55. Pubmed: 16105135 Link_out
                                                  21. Joubert LM, Manore MM: Exercise, nutrition, and homocysteine. Int J Sport Nutr Exerc Metab. 2006 Aug;16(4):341-61. Pubmed: 17136938 Link_out
                                                  22. Brosnan JT: Homocysteine and cardiovascular disease: interactions between nutrition, genetics and lifestyle. Can J Appl Physiol. 2004 Dec;29(6):773-80. Pubmed: 15630149 Link_out

                                                  Enzymes
                                                  Name: Methionine synthase
                                                  Reactions:
                                                  5-Methyltetrahydrofolic acid + Homocysteine unknown Tetrahydrofolic acid + L-Methionine details
                                                  Gene Name: MTR
                                                  Uniprot ID: Q99707 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: Betaine--homocysteine S-methyltransferase 1
                                                  Reactions:
                                                  Trimethylammonioacetate + Homocysteine unknown Dimethylglycine + L-Methionine details
                                                  Gene Name: BHMT
                                                  Uniprot ID: Q93088 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: Putative adenosylhomocysteinase 3
                                                  Reactions:
                                                  S-Adenosylhomocysteine + Water unknown Homocysteine + Adenosine details
                                                  Gene Name: AHCYL2
                                                  Uniprot ID: Q96HN2 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: Adenosylhomocysteinase
                                                  Reactions:
                                                  S-Adenosylhomocysteine + Water unknown Homocysteine + Adenosine details
                                                  Gene Name: AHCY
                                                  Uniprot ID: P23526 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: Putative adenosylhomocysteinase 2
                                                  Reactions:
                                                  S-Adenosylhomocysteine + Water unknown Homocysteine + Adenosine details
                                                  Gene Name: AHCYL1
                                                  Uniprot ID: O43865 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: Cystathionine beta-synthase
                                                  Reactions:
                                                  L-Serine + Homocysteine unknown L-Cystathionine + Water details
                                                  Gene Name: CBS
                                                  Uniprot ID: P35520 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA
                                                  Name: S-methylmethionine--homocysteine S-methyltransferase BHMT2
                                                  Reactions:
                                                  Trimethylammonioacetate + Homocysteine unknown Dimethylglycine + L-Methionine details
                                                  Gene Name: BHMT2
                                                  Uniprot ID: Q9H2M3 Link_out
                                                  Protein Sequence: FASTA
                                                  Gene Sequence: FASTA