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Record Information
Version5.0
StatusDetected and Quantified
Creation Date2005-11-16 15:48:42 UTC
Update Date2023-02-21 17:14:41 UTC
HMDB IDHMDB0000301
Secondary Accession Numbers
Metabolite Identification
Common NameUrocanic acid
DescriptionUrocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
Structure
Thumb
Synonyms
Chemical FormulaC6H6N2O2
Average Molecular Weight138.124
Monoisotopic Molecular Weight138.042927446
IUPAC Name(2E)-3-(1H-imidazol-4-yl)prop-2-enoic acid
Traditional Nametrans-urocanic acid
CAS Registry Number3465-72-3
SMILES
OC(=O)\C=C\C1=CNC=N1
InChI Identifier
InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1+
InChI KeyLOIYMIARKYCTBW-OWOJBTEDSA-N
Chemical Taxonomy
Description Belongs to the class of organic compounds known as imidazolyl carboxylic acids and derivatives. These are organic compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an imidazole ring.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassAzoles
Sub ClassImidazoles
Direct ParentImidazolyl carboxylic acids and derivatives
Alternative Parents
Substituents
  • Imidazolyl carboxylic acid derivative
  • Heteroaromatic compound
  • Azacycle
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboxylic acid derivative
  • Organic nitrogen compound
  • Organic oxygen compound
  • Organopnictogen compound
  • Organic oxide
  • Hydrocarbon derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Carbonyl group
  • Aromatic heteromonocyclic compound
Molecular FrameworkAromatic heteromonocyclic compounds
External Descriptors
Ontology
Physiological effectNot Available
Disposition
Biological locationRoute of exposureSource
Process
Role
Physical Properties
StateSolid
Experimental Molecular Properties
PropertyValueReference
Melting Point225 °CNot Available
Boiling PointNot AvailableNot Available
Water Solubility1.5 mg/mL at 17 °CNot Available
LogPNot AvailableNot Available
Experimental Chromatographic Properties

Experimental Collision Cross Sections

Adduct TypeData SourceCCS Value (Å2)Reference
[M-H]-MetCCS_train_neg118.77830932474
[M+H]+MetCCS_train_pos134.11130932474
[M-H]-Not Available121.6http://allccs.zhulab.cn/database/detail?ID=AllCCS00000321
[M+H]+Not Available135.5http://allccs.zhulab.cn/database/detail?ID=AllCCS00000321
Predicted Molecular Properties
Predicted Chromatographic Properties
Spectra
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biospecimen Locations
  • Blood
  • Feces
  • Saliva
  • Sweat
  • Urine
Tissue Locations
  • Epidermis
  • Liver
  • Placenta
Pathways
Normal Concentrations
Abnormal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothColorectal Cancer details
UrineDetected and Quantified6.872 umol/mmol creatinineChildren (1 - 13 years old)Not Specified
Eosinophilic esophagitis
    • Analysis of 30 no...
details
UrineDetected and Quantified158-202 umol/mmol creatinineAdolescent (13-18 years old)Not SpecifiedUrocanase deficiency details
Associated Disorders and Diseases
Disease References
Colorectal cancer
  1. Brown DG, Rao S, Weir TL, O'Malia J, Bazan M, Brown RJ, Ryan EP: Metabolomics and metabolic pathway networks from human colorectal cancers, adjacent mucosa, and stool. Cancer Metab. 2016 Jun 6;4:11. doi: 10.1186/s40170-016-0151-y. eCollection 2016. [PubMed:27275383 ]
Eosinophilic esophagitis
  1. Slae, M., Huynh, H., Wishart, D.S. (2014). Analysis of 30 normal pediatric urine samples via NMR spectroscopy (unpublished work). NA.
Urocanase deficiency
  1. Espinos C, Pineda M, Martinez-Rubio D, Lupo V, Ormazabal A, Vilaseca MA, Spaapen LJ, Palau F, Artuch R: Mutations in the urocanase gene UROC1 are associated with urocanic aciduria. J Med Genet. 2009 Jun;46(6):407-11. doi: 10.1136/jmg.2008.060632. Epub 2009 Mar 19. [PubMed:19304569 ]
Associated OMIM IDs
DrugBank IDDB01971
Phenol Explorer Compound IDNot Available
FooDB IDFDB007506
KNApSAcK IDNot Available
Chemspider ID643824
KEGG Compound IDC00785
BioCyc IDNot Available
BiGG ID35990
Wikipedia LinkUrocanic_acid
METLIN ID298
PubChem Compound736715
PDB IDNot Available
ChEBI ID30817
Food Biomarker OntologyNot Available
VMH IDURCAN
MarkerDB IDMDB00000140
Good Scents IDNot Available
References
Synthesis ReferenceYamamoto, Kozo; Sato, Tadashi; Tosa, Tetsuya; Chibata, Ichiro. Continuous production of urocanic acid by immobilized Achromobacter liquidum cells. Biotechnology and Bioengineering (1974), 16(12), 1601-10.
Material Safety Data Sheet (MSDS)Not Available
General References

Enzymes

General function:
Involved in histidine ammonia-lyase activity
Specific function:
Not Available
Gene Name:
HAL
Uniprot ID:
P42357
Molecular weight:
49122.09
Reactions
Histidine → Urocanic acid + Ammoniadetails
General function:
Involved in urocanate hydratase activity
Specific function:
Not Available
Gene Name:
UROC1
Uniprot ID:
Q96N76
Molecular weight:
80911.275
Reactions
4-Imidazolone-5-propionic acid → Urocanic acid + Waterdetails