Abstract
Photosystem II reaction centers evolve O2 in the dark when H2O2 is added as a substrate. Although some of this activity can be attributed to catalase, as much as 75% of the activity was not affected by the addition of 1 mM KCN. Several lines of evidence demonstrate that this KCN-insensitive O2 evolution from H2O2 in the dark is catalyzed by the cycling of S states in the oxygen-evolving complex including: (1) inactivation of H2O2-mediated O2 evolution by Ca/EDTA washing; (2) susceptibility of the activity to inhibition by amines like ammonia and Tris; (3) inhibition by CCCP which is known to accelerate the rate of deactivation of the S2 state and; (4) a direct dependence of the rate of O2 evolution on the presence of calcium and (5) chloride.
Original language | English (US) |
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Pages (from-to) | 8-14 |
Number of pages | 7 |
Journal | BBA - Bioenergetics |
Volume | 891 |
Issue number | 1 |
DOIs | |
State | Published - Mar 25 1987 |
Externally published | Yes |
Keywords
- Hydrogen peroxide
- Oxygen evolution
- Oxygen-evolving complex
- Photosystem II
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology