title: Interference-based electrochemical biosensor for the measurement of the concentration and isomer ratio of urocanic acid.
abstract: Urocanic acid (UCA) is known to be synthesized as the trans isomer (trans-UCA) in the skin, and trans-UCA is transformed by UV light to the cis isomer (cis-UCA), which may be involved in photoimmunosuppression. An electrochemical method has been developed for the measurement of the concentration and isomer ratio of UCA. A heme peptide-modified electrode (HP electrode) reduces hydrogen peroxide at +150 mV vs Ag/AgCl, and the reduction current is inhibited by UCA. Since cis-UCA is a stronger inhibitor than trans-UCA, irradiation of a sample solution with UV light increases the percent inhibition. The concentration and isomer ratio of UCA in the sample solution can be estimated from the values of percent inhibition before and after the UV irradiation.
authors.affiliation: Institute of Industrial Science, University of Tokyo, Japan. tatsuma@iis.u-to-kyo.ac.jp
authors.forename: Tetsu
authors.initials: T
authors.lastname: Tatsuma
authors.forename: Kei
authors.initials: K
authors.lastname: Okamura
authors.forename: Kikuo
authors.initials: K
authors.lastname: Komori
authors.forename: Akira
authors.initials: A
authors.lastname: Fujishima
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D006861:Hydrogen Peroxide / Q000737:chemistry; D014466:Ultraviolet Rays; D014560:Urocanic Acid / Q000032:analysis*
chemical_list: D006861:Hydrogen Peroxide; D014560:Urocanic Acid