The involvement of photosystem II-generated H2O2 in photoinhibition.
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 photoinhibited 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.
Bradley
R L
RL
Department of Botany, Arizona State University, Tempe 85287-1601.
Long
K M
KM
Frasch
W D
WD
D002712:Chlorides / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007700:Kinetics; D008027:Light; D008345:Manganese / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism* / Q000528:radiation effects; D045332:Photosystem II Protein Complex; D010944:Plants
D002712:Chlorides; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D008345:Manganese; D006861:Hydrogen Peroxide; D010100:Oxygen