1.0 2010-04-08 22:04:46 UTC 2019-11-26 02:55:37 UTC FDB000921 Urocanic acid Urocanic acid is an intermediate in the catabolism of L-histidine.; Urocanic 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. Urocanic acid is found in mung bean. (2e)-3-(1H-Imidazol-4-yl)acrylate (e)-3-(1H-Imidazol-4-yl)-2-propenoate 3-(1H-Imidazol-4-yl)-2-propenoate 3-(1H-Imidazol-4-yl)-2-propenoic acid 3-(1H-Imidazol-4-yl)-2-propenoic acid, 9CI 3-(1H-Imidazol-4-yl)acrylate 3-(1H-Imidazol-4-yl)acrylic acid 3-(4-Imidazolyl)acrylate 3-(4-Imidazolyl)acrylic acid 4-Imidazoleacrylic acid, 8CI 5-Imidazoleacrylate 5-Imidazoleacrylate;imidazoleacrylic acid 5-Imidazoleacrylic acid Imidazole-4-acrylate Imidazole-4-acrylic acid Imidazoleacrylic acid Trans-urocanate Urocanate Urocaninic acid C6H6N2O2 138.124 138.042927446 (2Z)-3-(1H-imidazol-5-yl)prop-2-enoic acid (2Z)-3-(3H-imidazol-4-yl)prop-2-enoic acid 104-98-3 OC(=O)\C=C/C1=CN=CN1 InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1- LOIYMIARKYCTBW-UPHRSURJSA-N 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. Imidazolyl carboxylic acids and derivatives Organic compounds Organoheterocyclic compounds Azoles Imidazoles Aromatic heteromonocyclic compounds Azacyclic compounds Carbonyl compounds Carboxylic acids Heteroaromatic compounds Hydrocarbon derivatives Monocarboxylic acids and derivatives Organic oxides Organonitrogen compounds Organopnictogen compounds Aromatic heteromonocyclic compound Azacycle Carbonyl group Carboxylic acid Carboxylic acid derivative Heteroaromatic compound Hydrocarbon derivative Imidazolyl carboxylic acid derivative Monocarboxylic acid or derivatives Organic nitrogen compound Organic oxide Organic oxygen compound Organonitrogen compound Organooxygen compound Organopnictogen compound urocanic acid Solid logp 0.00 ALOGPS logs -0.82 ALOGPS solubility 2.10e+01 g/l ALOGPS melting_point Mp 243-245° logp -0.88 ChemAxon pka_strongest_acidic 3.21 ChemAxon pka_strongest_basic 6.82 ChemAxon iupac (2Z)-3-(1H-imidazol-5-yl)prop-2-enoic acid ChemAxon average_mass 138.124 ChemAxon mono_mass 138.042927446 ChemAxon smiles OC(=O)\C=C/C1=CN=CN1 ChemAxon formula C6H6N2O2 ChemAxon inchi InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1- ChemAxon inchikey LOIYMIARKYCTBW-UPHRSURJSA-N ChemAxon polar_surface_area 65.98 ChemAxon refractivity 35.89 ChemAxon polarizability 12.75 ChemAxon rotatable_bond_count 2 ChemAxon acceptor_count 3 ChemAxon donor_count 2 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon Ammonia Recycling SMP00009 map00910 Histidine Metabolism SMP00044 map00340 Specdb::CMs 14756 Specdb::CMs 43744 Specdb::MsMs 103935 Specdb::MsMs 103936 Specdb::MsMs 103937 Specdb::MsMs 170103 Specdb::MsMs 170104 Specdb::MsMs 170105 Specdb::NmrOneD 301845 Specdb::NmrOneD 301846 Specdb::NmrOneD 301847 Specdb::NmrOneD 301848 Specdb::NmrOneD 301849 Specdb::NmrOneD 301850 Specdb::NmrOneD 301851 Specdb::NmrOneD 301852 Specdb::NmrOneD 301853 Specdb::NmrOneD 301854 Specdb::NmrOneD 301855 Specdb::NmrOneD 301856 Specdb::NmrOneD 301857 Specdb::NmrOneD 301858 Specdb::NmrOneD 301859 Specdb::NmrOneD 301860 Specdb::NmrOneD 301861 Specdb::NmrOneD 301862 Specdb::NmrOneD 301863 Specdb::NmrOneD 301864 HMDB00301 URO #<Reference:0x00005612732f46e0> #<Reference:0x00005612732f44b0> #<Reference:0x00005612732f42f8> #<Reference:0x00005612732f40f0> #<Reference:0x00005612732f3d80> #<Reference:0x00005612732f3ad8> #<Reference:0x00005612732f3830> #<Reference:0x00005612732f3628> Mung bean Type 1 specific Vigna radiata 157791 Histidine ammonia-lyase P42357 HAL