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Record Information
Version3.6
Creation Date2005-11-16 15:48:42 UTC
Update Date2014-12-01 22:59:31 UTC
HMDB IDHMDB00301
Secondary Accession Numbers
  • HMDB02280
Metabolite Identification
Common NameUrocanic acid
DescriptionUrocanic acid 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 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.
Structure
Thumb
Synonyms
  1. 3-(1H-Imidazol-4-yl)-2-propenoate
  2. 3-(1H-Imidazol-4-yl)-2-propenoic acid
  3. 3-(1H-Imidazol-4-yl)acrylate
  4. 3-(1H-Imidazol-4-yl)acrylic acid
  5. 3-(4-Imidazolyl)acrylate
  6. 3-(4-Imidazolyl)acrylic acid
  7. 5-Imidazoleacrylate
  8. 5-Imidazoleacrylic acid
  9. Imidazole-4-acrylate
  10. Imidazole-4-acrylic acid
  11. Imidazoleacrylic acid
  12. Urocanate
  13. Urocanic acid
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 Number104-98-3
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
KingdomOrganic Compounds
Super ClassAromatic Heteromonocyclic Compounds
ClassAzoles
Sub ClassImidazoles
Other Descriptors
  • Aromatic Heteromonocyclic Compounds
  • urocanic acid(ChEBI)
Substituents
  • Allyl Alcohol
  • Carboxylic Acid
  • Enone
Direct ParentImidazolyl Carboxylic Acids and Derivatives
Ontology
StatusDetected and Quantified
Origin
  • Endogenous
Biofunction
  • Component of Histidine metabolism
  • Component of Nitrogen metabolism
ApplicationNot Available
Cellular locations
  • Cytoplasm (predicted from logP)
Physical Properties
StateSolid
Experimental Properties
PropertyValueReference
Melting Point225 °CNot Available
Boiling PointNot AvailableNot Available
Water Solubility1.5 mg/mL at 17 °CNot Available
LogPNot AvailableNot Available
Predicted Properties
PropertyValueSource
Water Solubility42.5ALOGPS
logP0.22ALOGPS
logP-1ChemAxon
logS-0.51ALOGPS
pKa (Strongest Acidic)3.85ChemAxon
pKa (Strongest Basic)6.13ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area65.98 Å2ChemAxon
Rotatable Bond Count2ChemAxon
Refractivity35.57 m3·mol-1ChemAxon
Polarizability13.09 Å3ChemAxon
Spectra
SpectraGC-MSMS/MSLC-MS1D NMR2D NMR
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biofluid Locations
  • Blood
  • Feces
  • Saliva
  • Urine
Tissue Location
  • Liver
  • Skin
Pathways
NameSMPDB LinkKEGG Link
Ammonia RecyclingSMP00009map00910
Histidine MetabolismSMP00044map00340
Normal Concentrations
BiofluidStatusValueAgeSexConditionReferenceDetails
BloodDetected and Quantified0.43 +/- 0.33 uMAdult (>18 years old)BothNormal details
FecesDetected but not QuantifiedNot ApplicableAdult (>18 years old)Both
Normal
details
SalivaDetected and Quantified5.49 +/- 5.14 uMAdult (>18 years old)Male
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified5.78 +/- 13.1 uMAdult (>18 years old)Both
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified6.13 +/- 16.3 uMAdult (>18 years old)Female
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified0.942 +/- 1.54 uMAdult (>18 years old)Female
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified7.25 +/- 12.7 uMAdult (>18 years old)Both
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified1.04 +/- 2.19 uMAdult (>18 years old)Female
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified1.23 +/- 1.70 uMAdult (>18 years old)Female
Normal
    • Sugimoto et al. (...
details
SalivaDetected and Quantified1.49 +/- 1.98 uMAdult (>18 years old)Both
Normal
    • Sugimoto et al. (...
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot ApplicableAdult (>18 years old)Male
Normal
details
UrineDetected and Quantified0.29 (0.0-0.78) umol/mmol creatinineAdult (>18 years old)BothNormal
    • Geigy Scientific ...
    • West Cadwell, N.J...
    • Basel, Switzerlan...
details
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB01971
DrugBank Metabolite IDNot Available
Phenol Explorer Compound IDNot Available
Phenol Explorer Metabolite IDNot Available
FoodDB IDFDB000921
KNApSAcK IDNot Available
Chemspider ID643824
KEGG Compound IDC00785
BioCyc IDUROCANATE
BiGG ID35990
Wikipedia LinkUrocanic acid
NuGOwiki LinkHMDB00301
Metagene LinkHMDB00301
METLIN ID298
PubChem Compound736715
PDB IDURO
ChEBI ID30817
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)Download (PDF)
General References
  1. Sastry CM, Whitmore SE, Breysse PN, Morison WL, Strickland PT: The effect of clinical UVA/B exposures on urinary urocanic acid isomer levels in individuals with caucasian type (II/III) skin types. Dermatol Online J. 2005 Dec 1;11(3):1. Pubmed: 16409897
  2. Hug DH, Hunter JK, Dunkerson DD: The potential role for urocanic acid and sunlight in the immune suppression associated with protein malnutrition. J Photochem Photobiol B. 1998 Jul 10;44(2):117-23. Pubmed: 9757593
  3. Snellman E, Jansen CT, Laihia JK, Milan T, Koulu L, Leszczynski K, Pasanen P: Urocanic acid concentration and photoisomerization in Caucasian skin phototypes. Photochem Photobiol. 1997 May;65(5):862-5. Pubmed: 9155258
  4. Schwarz W, Langer K, Haag A: High-performance liquid chromatographic determination of (Z)-and (E)-urocanic acid in human skin. J Chromatogr. 1984 Sep 14;310(1):188-92. Pubmed: 6501514
  5. Hermann K, Abeck D: Determination of histidine and urocanic acid isomers in the human skin by high-performance capillary electrophoresis. J Chromatogr B Biomed Sci Appl. 2000 Nov 10;749(1):41-7. Pubmed: 11129077
  6. Kinuta M, Kinuta K, Yamada H, Abe T, Yoshida Y, Araki K, Li SA, Otsuka A, Nakanishi A, Moriyama Y, Takei K: Formation of S-[2-carboxy-1-(1H-imidazol-4-yl) ethyl]glutathione, a new metabolite of L-histidine, from cis-urocanic acid and glutathione by the action of glutathione S-transferase. Electrophoresis. 2003 Sep;24(18):3212-8. Pubmed: 14518047
  7. Yokoya S, Tokuhiro E, Suwa S, Maesaka H: Measurement of the skin urocanic acid content in normal and histidinemic infants. Eur J Pediatr. 1983 Sep;140(4):330-2. Pubmed: 6628454
  8. Morrison H: Photochemistry and photobiology of urocanic acid. Photodermatol. 1985 Jun;2(3):158-65. Pubmed: 3895185

Enzymes

General function:
Involved in histidine ammonia-lyase activity
Specific function:
Not Available
Gene Name:
HAL
Uniprot ID:
P42357
Molecular weight:
49122.09
Reactions
L-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