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Metabolic Modeling Tutorial
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Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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Escherichia coli K-12 substr. MG1655 Compound: L-homocysteine

Synonyms: homo-cys, homocysteine

Superclasses: a protein-bound uremic retention solute
an amino acid or its derivative an amino acid an alpha amino acid a non-standard alpha amino acid

Component of: MetR-L-homocysteine

Summary from MetaCyc:
L-homocysteine is one of the major protein-bound uremic retention solutes.

At concentrations encountered during uremia L-homocysteine predisposes uremic patients to cardiovascular disease through impairment of endothelial and smooth muscle cell functions.

Chemical Formula: C4H9NO2S

Molecular Weight: 135.18 Daltons

Monoisotopic Molecular Weight: 135.0353992283 Daltons

SMILES: C(C(CCS)[N+])(=O)[O-]

InChI: InChI=1S/C4H9NO2S/c5-3(1-2-8)4(6)7/h3,8H,1-2,5H2,(H,6,7)/t3-/m0/s1

InChIKey: InChIKey=FFFHZYDWPBMWHY-VKHMYHEASA-N

Unification Links: CAS:454-28-4 , CAS:6027-13-0 , ChEBI:58199 , HMDB:HMDB00742 , IAF1260:45588 , KEGG:C00155 , MetaboLights:MTBLC58199 , PubChem:6971015

Standard Gibbs Free Energy of Change Formation (ΔfG in kcal/mol): -81.77

Reactions known to consume the compound:

methionine biosynthesis I :
L-homocysteine + an N5-methyl-tetrahydrofolate → L-methionine + a tetrahydrofolate
L-homocysteine + N5-methyl--tetrahydropteroyl tri-L-glutamate → L-methionine + tetrahydropteroyl tri-L-glutamate

N10-formyl-tetrahydrofolate biosynthesis :
L-homocysteine + an N5-methyl-tetrahydrofolate → L-methionine + a tetrahydrofolate

S-adenosyl-L-methionine cycle I :
L-homocysteine + N5-methyl--tetrahydropteroyl tri-L-glutamate → L-methionine + tetrahydropteroyl tri-L-glutamate

Not in pathways:
L-homocysteine + S-adenosyl-L-methionine → L-methionine + S-adenosyl-L-homocysteine + H+

Reactions known to produce the compound:

autoinducer AI-2 biosynthesis I , S-adenosyl-L-methionine cycle I :
S-ribosyl-L-homocysteine → L-homocysteine + (S)-4,5-dihydroxypentan-2,3-dione

methionine biosynthesis I :
L-cystathionine → 2-aminoprop-2-enoate + L-homocysteine + H+

Not in pathways:
L-cystathionine + H2O → ammonium + pyruvate + L-homocysteine

In Reactions of unknown directionality:

Not in pathways:
MetR + L-homocysteine = MetR-L-homocysteine
S-methyl-L-methionine + L-homocysteine = 2 L-methionine + H+


a 5-L-glutamyl-[peptide][periplasmic space] + an amino acid[periplasmic space] = a 5-L-glutamyl-amino acid[periplasmic space] + a peptide[periplasmic space]

Enzymes inhibited by L-homocysteine, sorted by the type of inhibition, are:

Inhibitor (Competitive) of: homoserine kinase [Theze74, Burr76, Comment 1]

Transcription Units regulated by related protein MetR-L-homocysteine (4 total):


References

Brunet03: Brunet P, Dou L, Cerini C, Berland Y (2003). "Protein-bound uremic retention solutes." Adv Ren Replace Ther 10(4);310-20. PMID: 14681860

Burr76: Burr B, Walker J, Truffa-Bachi P, Cohen GN (1976). "Homoserine kinase from Escherichia coli K12." Eur J Biochem 1976;62(3);519-26. PMID: 177283

Theze74: Theze J, Kleidman L, St Girons I (1974). "Homoserine kinase from Escherichia coli K-12: properties, inhibition by L-threonine, and regulation of biosynthesis." J Bacteriol 1974;118(2);577-81. PMID: 4364023


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 18.5 on Sat Dec 20, 2014, biocyc13.