Hydrogen peroxide as an alternate substrate for the oxygen-evolving complex
1987; Elsevier BV; Volume: 891; Issue: 1 Linguagem: Inglês
10.1016/0005-2728(87)90077-6
ISSN1879-2650
Autores Tópico(s)Mitochondrial Function and Pathology
ResumoPhotosystem 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.
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