Compound
L-homocysteine
An amino acid zwitterion arising from transfer of a proton from the carboxy to the amino group of L-homocysteine; major species at pH 7.3.
Definition from ChEBI (CHEBI:58199), read 2026-09-23. CC BY 4.0.
Structure
Loading the model…
- Class
- Organic compound
- Formula
- C4H9NO2S
- Mass
- 135.188 g/mol
- Charge
- 0
- InChIKey
- FFFHZYDWPBMWHY-VKHMYHEASA-N
- SMILES
- [NH3+][C@@H](CCS)C(=O)[O-]
- Look it up
- ChEBIPubChemBy InChIKey
Identity from ChEBI, geometry from PubChem. Not evidence.
What it touches on the way
Mechanistic reach
7 entities
7 entities reached.
0 reported hops7 assembled from the scaffold
- MARS1ProteinUNIPROT:P56192substrate ofInferred only58 paths29 endpoints
- MTRProteinUNIPROT:Q99707substrate ofInferred only40 paths40 endpoints
- CBSProteinUNIPROT:P35520substrate ofInferred only32 paths32 endpoints
- CTHProteinUNIPROT:P32929substrate ofInferred only21 paths21 endpoints
- BHMTProteinUNIPROT:Q93088substrate ofInferred only14 paths14 endpoints
- BHMT2ProteinUNIPROT:Q9H2M3substrate ofInferred only5 paths5 endpoints
- L-methionineCompoundCHEBI:57844converted toInferred only2 paths1 endpoint
What the reference databases state
Statements
14 statements
14 statements · 1 reference database · Subject: L-homocysteine · Sources: Rhea
- L-homocysteine thiolactone is converted to L-homocysteineCompoundRhea RHEA:83867Inferred only
- L-homocysteine is converted to L-homocysteine thiolactoneCompoundRhea RHEA:83875Inferred only
- L-homocysteine is converted to L-homocysteinyl-AMPCompoundRhea RHEA:83879Inferred only
- L-methionine is converted to L-homocysteineCompoundRhea RHEA:21820Inferred only
- L-homocysteine is converted to L-methionineCompoundRhea RHEA:21820Inferred only
- L-homocysteine is converted to L,L-cystathionineCompoundRhea RHEA:10112Inferred only
- L,L-cystathionine is converted to L-homocysteineCompoundRhea RHEA:10112Inferred only
- L-homocysteine is a substrate of BHMTProteinRhea RHEA:22336Inferred only
- L-homocysteine is a substrate of BHMT2ProteinRhea RHEA:26337Inferred only
- L-homocysteine is a substrate of CBSProteinRhea RHEA:10112Inferred only
- L-homocysteine is a substrate of CTHProteinRhea RHEA:14501Inferred only
- L-homocysteine is a substrate of MARS1ProteinRhea RHEA:83875Inferred only
Show the remaining 2
- L-homocysteine is a substrate of MARS1ProteinRhea RHEA:83879Inferred only
- L-homocysteine is a substrate of MTRProteinRhea RHEA:11172Inferred only
Reactions
24 reactions
L-homocysteine+L-seryl residueL,L-cystathionine+water
Catalysed by CBS
Reaction pageDirection not assertedBalanced
Rhea RHEA:10112CC BY 4.0Reference data
(6S)-5-methyl-5,6,7,8-tetrahydrofolate+L-homocysteine(6S)-5,6,7,8-tetrahydrofolate+L-methionine
Catalysed by MTR
Reaction pageLeft to rightBalanced
Rhea RHEA:11172CC BY 4.0Reference data
CHEBI:140613+2glutathione2L-homocysteine+glutathione disulfide
Reaction pageDirection not assertedBalanced
Rhea RHEA:11464CC BY 4.0Reference data
L,L-cystathionine+waterL-homocysteine+pyruvate+ammonium
Reaction pageDirection not assertedBalanced
Rhea RHEA:13965CC BY 4.0Reference data
L-homocysteine+water2-oxobutanoate+hydrogen sulfide+ammonium+hydron
Catalysed by CTH
Reaction pageLeft to rightBalanced
Rhea RHEA:14501CC BY 4.0Reference data
CHEBI:58195CHEBI:29484+L-homocysteine
Reaction pageDirection not assertedBalanced
Rhea RHEA:17753CC BY 4.0Reference data
CHEBI:58207+L-homocysteineCHEBI:58140+L-methionine
Reaction pageDirection not assertedBalanced
Rhea RHEA:21196CC BY 4.0Reference data
S-adenosyl-L-homocysteine+waterL-homocysteine+adenosine
Catalysed by AHCY
Reaction pageLeft to rightBalanced
Rhea RHEA:21708CC BY 4.0Reference data
L-homocysteine+S-adenosyl-L-methionineL-methionine+S-adenosyl-L-homocysteine+hydron
Reaction pageDirection not assertedBalanced
Rhea RHEA:21820CC BY 4.0Reference data
L-homocysteine+glycine betaineN,N-dimethylglycine+L-methionine
Catalysed by BHMT
Reaction pageLeft to rightBalanced
Rhea RHEA:22336CC BY 4.0Reference data
CHEBI:16471+L-homocysteineCHEBI:18071+L-methionine+hydron
Reaction pageDirection not assertedBalanced
Rhea RHEA:22788CC BY 4.0Reference data
S-methyl-L-methionine+L-homocysteine2L-methionine+hydron
Catalysed by BHMT2
Reaction pageDirection not assertedBalanced
Rhea RHEA:26337CC BY 4.0Reference data
Other names
1 name
Resolves to: L-homocysteine
- Systematic name
- (2S)-2-azaniumyl-4-sulfanylbutanoate