Accession NumberHMDB00301
Common_NameUrocanic acid
DescriptionUrocanic 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
Chemical_IUPAC_Name3-(3H-imidazol-4-yl)prop-2-enoic acid
Chemical FormulaC6H6N2O2
Sample ConcentrationNot Available
Mass Value1
Mass Unitmg
ManufacturerQuattro_QQQ
AnalyzerTriple_Quad
DeliveryFlow_Injection
IonizationPositive
Predicted 1H NMR SpectrumDownload
Predicted 1H NMR PeaklistDownload
Predicted 13C NMR SpectrumDownload
Predicted 13C NMR PeaklistDownload
Sample ConcentrationNot Available
Mass ValueNot Available
Mass UnitNot Available
ManufacturerNot Available
FrequencyNot Available
1H NMR Spectrum
Sample ConcentrationNot Available
Mass ValueNot Available
Mass UnitNot Available
ManufacturerNot Available
FrequencyNot Available
13C NMR SpectrumNot Available
Low Energy Voltage10
Low Energy SpectrumDownload
Low Energy PeaklistDownload
Medium Energy SpectrumDownload
High Energy SpectrumDownload