title: Simultaneous measurements of photocurrents and H2O2 evolution from solvent exposed photosystem 2 complexes.
abstract: In plants, algae, and cyanobacteria, photosystem 2 (PS2) catalyzes the light driven oxidation of water. The main products of this reaction are protons and molecular oxygen. In vitro, however, it was demonstrated that reactive oxygen species like hydrogen peroxide are obtained as partially reduced side products. The transition from oxygen to hydrogen peroxide evolution might be induced by light triggered degradation of PS2's active center. Herein, the authors propose an analytical approach to investigate light induced bioelectrocatalytic processes such as PS2 catalyzed water splitting. By combining chronoamperometry and fluorescence microscopy, the authors can simultaneously monitor the photocurrent and the hydrogen peroxide evolution of light activated, solvent exposed PS2 complexes, which have been immobilized on a functionalized gold electrode. The authors show that under limited electron mediation PS2 displays a lower photostability that correlates with an enhanced H2O2 generation as a side product of the light induced water oxidation.
authors.affiliation: Department of Physical Chemistry II, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Vöpel
authors.affiliation: Center for Electrochemical Sciences, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: En
authors.initials: E
authors.lastname: Ning Saw
authors.affiliation: Department of Plant Biochemistry, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Hartmann
authors.affiliation: Center for Electrochemical Sciences, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Rhodri
authors.initials: R
authors.lastname: Williams
authors.affiliation: Center for Electrochemical Sciences, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Müller
authors.affiliation: Center for Electrochemical Sciences, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
authors.affiliation: Center for Electrochemical Sciences, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Plumeré
authors.affiliation: Department of Plant Biochemistry, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Nowaczyk
authors.affiliation: Department of Physical Chemistry II, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Ebbinghaus
authors.affiliation: Department of Plant Biochemistry, Ruhr University Bochum, Universitätstr. 150, 44801 Bochum, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Rögner
mesh_terms: D000458:Cyanobacteria / Q000201:enzymology*; D004560:Electricity; D055664:Electrochemical Techniques; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008027:Light; D008856:Microscopy, Fluorescence; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D012997:Solvents
chemical_list: D045332:Photosystem II Protein Complex; D012997:Solvents; D006861:Hydrogen Peroxide