Change search
ReferencesLink to record
Permanent link

Direct link
Electrochemically produced hydrogen peroxide affects Joliot-type oxygen-evolution measurements of photosystem II
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2014 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1837, no 9, 1411-1416 p.Article in journal (Refereed) Published
Abstract [en]

The main technique employed to characterize the efficiency of water-splitting in photosynthetic preparations in terms of miss and double hit parameters and for the determination of S-i (i = 2,3,0) state lifetimes is the measurement of flash-induced oxygen oscillation pattern on bare platinum (Joliot-type) electrodes. We demonstrate here that this technique is not innocent. Polarization of the electrode against an Ag/AgCl electrode leads to a time-dependent formation of hydrogen peroxide by two-electron reduction of dissolved oxygen continuously supplied by the flow buffer. While the miss and double hit parameters are almost unaffected by H2O2, a time dependent reduction of S-1 to S-1 occurs over a time period of 20 mm. The S-1 reduction can be largely prevented by adding catalase or by removing O-2 from the flow buffer with N-2. Importantly, we demonstrate that even at the shortest possible polarization times (40 s in our set up) the S-2 and S-0 decays are significantly accelerated by the side reaction with H2O2. The removal of hydrogen peroxide leads to unperturbed S-2 state data that reveal three instead of the traditionally reported two phases of decay. In addition, even under the best conditions (catalase + N-2; 40 s polarization) about 4% of S-1 state is observed in well dark-adapted samples, likely indicating limitations of the equal fit approach. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy.

Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 1837, no 9, 1411-1416 p.
Keyword [en]
photosystem II (PSII), oxygen evolving complex (OEC), water oxidation, manganese, hydrogen peroxide (H2O2)
National Category
Biochemistry and Molecular Biology
URN: urn:nbn:se:umu:diva-94141DOI: 10.1016/j.bbabio.2014.01.013ISI: 000341474300005OAI: diva2:753713
Available from: 2014-10-08 Created: 2014-10-06 Last updated: 2015-11-26Bibliographically approved
In thesis
1. Oxidation and reduction reactions of the water-oxidizing complex in photosystem II
Open this publication in new window or tab >>Oxidation and reduction reactions of the water-oxidizing complex in photosystem II
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Oxidations- och reduktionsreaktioner av det vattenoxiderande komplexet i fotosystem II
Abstract [en]

The oxygen that we breathe and food that we eat are products of the natural photosynthesis. Molecular oxygen is crucial for life on Earth owing to its role in the glycolysis and citric acid pathways that yield in aerobic organisms the energy-rich ATP molecules. Photosynthetic water oxidation, which produces molecular oxygen from water and sunlight, is performed by higher plants, algae and cyanobacteria. Within the molecular structure of a plant cell, photosynthesis is performed by a specific intracellular organelle – the chloroplast. Chloroplasts contain a membrane system, the thylakoid membrane, which comprises lipids, quinones and a very high content of protein complexes. The unique photosynthetic oxidation of water into molecular oxygen, protons and electrons is performed by the Mn4CaO5 cluster in photosystem II (PSII) complex. Understanding the mechanism of water oxidation by Mn4CaO5 cluster is one of the great challenges in science nowadays. When the mechanism of this process is fully understood, artificial photosynthetic systems can be designed that have high efficiencies of solar energy conversion by imitating the fundamental principle of natural system. These systems can be used in future for generation of fuels from sunlight.


In this thesis, the efficiency of water-splitting process in natural photosynthetic preparations was studied by measuring the flash-induced oxygen evolution pattern (FIOP). The overall aim is to achieve a deeper understanding of oxygen evolving mechanism of the Mn4O5Ca cluster via developing a complete kinetic and energetic model of the light-induced redox reactions within PSII complex. On the way to reach this goal, the hydrogen peroxide that is electrochemically generated on surface of Pt-cathode was discovered. The chemical effect of electrochemically produced H2O2 that can interfere in the oxygen evolution pathway or change the observed FIOP data was demonstrated. Therefore, in order to record the clean FIOP data that are further characterized by global fitting program (GFP), H2O2 has to be abolished by catalase addition and by purging the flow buffer of the Joliot-type electrode with nitrogen gas.   


After FIOPs free of H2O2-induced effects were achieved, these clean data were then applied to a global fitting approach (GFP) in order to (i) result a comprehensive figure of all S-state decays whose kinetic rates were simultaneously analyzed in a high reliability and consistency, (ii) the dependence of miss parameter on S-state transitions and the oxidation state of tyrosine D (YD) can be tested, (iii) how dependent of all S-state re-combinations (to S1 state) on the various pH/pD values can be also determined in case of using Cyanidioschyzon merolae (C. merolae) thylakoids. Our data support previous suggestions that the S0 → S1 and S1 → S2 transitions involve low or no misses, while high misses occur in the S2 → S3 transition or the S3 → S0 transition. Moreover, the appearance of very slow S2 decay was clearly observed by using the GFP analysis, while there are no evidences of very slow S3 decay were recorded under all circumstances. The unknown electron donor for the very slow S2 decay which can be one of the substances of PSII-protective branch (i.e. cytochrome b559, carotenoid or ChlZ) will be determined in further researches.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2015. 57 p.
Photosystem II (PSII), oxidation, reduction, flash induced oxygen evolution pattern (FIOP), water, oxygen, global fitting program (GFP), thylakoids
National Category
Chemical Sciences
Research subject
Physical Chemistry
urn:nbn:se:umu:diva-111862 (URN)978-91-7601-387-8 (ISBN)
Public defence
2015-12-18, KB3B1, KBC huset, Umeå, 13:00 (English)
Available from: 2015-11-27 Created: 2015-11-24 Last updated: 2015-11-26Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Pham, Long VoMessinger, Johannes
By organisation
Department of Chemistry
In the same journal
Biochimica et Biophysica Acta - Bioenergetics
Biochemistry and Molecular Biology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 124 hits
ReferencesLink to record
Permanent link

Direct link