title: Voltammetric and spectroelectrochemical characterization of a water-soluble viologen polymer and its application to electron-transfer mediator for enzyme-free regeneration of NADH.
abstract: A water-soluble polyxylylviologen (PXV(2+)) was characterized with a view to making use of it as a redox electron-transfer (ET) mediator. Cyclic voltammetric and spectropotentiometric studies showed (i) that PXV(2+) gives two redox waves centering at -0.40 and -0.83 V (vs. Ag/AgCl (3.3 mol dm(-3) KCl)) and (ii) that the lifetime of its monocation radical (PXV(+.)) is two orders of magnitude greater than that of the well-utilized dimethyl viologen monocation radical. Subsequently, the reaction of the PXV(2+/+.) couple with NAD(+) was evaluated in the similar manners as above. On the basis of this evaluation and the bioluminescence assay using bacterial NADH/FMN oxidoreductase and luciferase, it was shown (i) that the PXV(2+/+.) couple functions as a useful electron-transfer mediator and (ii) that PXV(+.) reacts with NAD(+), leading to generation of the enzymatically active NADH, in the absence of any reductases.
authors.affiliation: Department of Polymer Science and Engineering, Kyoto Institute of Technology, Kyoto 606-8585, Sakyo, Japan. karatani@ipc.kit.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Karatani
authors.forename: Naohisa
authors.initials: N
authors.lastname: Wada
authors.forename: Tohru
authors.initials: T
authors.lastname: Sugimoto
mesh_terms: D004579:Electron Transport; D009243:NAD / Q000737:chemistry* / Q000378:metabolism; D011108:Polymers / Q000737:chemistry*; D014755:Viologens / Q000737:chemistry*
chemical_list: D011108:Polymers; D014755:Viologens; D009243:NAD