has role chromophore imidazoles urocanate urocanic acid Wikipedia:Urocanic_acid 3-imidazol-4-ylacrylic acid PDBeChem:URO 3-(1H-imidazol-4-yl)prop-2-enoic acid CHEBI:27248 3-(1H-imidazol-4-yl)-2-propenoic acid HMDB:HMDB0000301 MetaCyc:UROCANATE ECMDB:ECMDB21396 An alpha,beta-unsaturated monocarboxylic acid that is prop-2-enoic acid substituted by a 1H-imidazol-4-yl group at position 3. It is a metabolite of hidtidine. human metabolite alpha,beta-unsaturated monocarboxylic acid