The involvement of photosystem II-generated H2O2 in photoinhibition

Ryan L. Bradley, Krista M. Long, Wayne Frasch

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


The involvement of H2O2 generated by photosystem II (PSII) in the process of photoinhibition of thylakoids with a functional oxygen-evolving complex (OEC) was investigated. The rate of photoinhibition was decreased to the rate of loss of activity in the dark when bovine Fe-catalase was present during the photoinhibitory illumination. Photoinhibition was accelerated for both Cl--depleted and Cl--sufficient thylakoids when KCN was present to inhibit the thylakoid-bound Fe-catalase. We propose that these preparations become photoinhibed by reactions with H2O2 produced via oxidation of water by the Cl--depleted OEC and by reduction of O2 at the QB site when PSII is illuminated without an electron acceptor.

Original languageEnglish (US)
Pages (from-to)209-213
Number of pages5
JournalFEBS Letters
Issue number1-2
StatePublished - Jul 29 1991


  • D1 protein
  • HO
  • Photoinhibition
  • Photosystem II

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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