Abstract
The rise time, of Signal IIf and the decay time of P-680+ have been measured kinetically as a function of pH by using EPR. The Photosystem II-enriched preparations which were used as samples were derived from spinach chloroplasts, and they evolved oxygen before Tris washing. The onset kinetics of Signal IIf are in agreement, within experimental error, with the fast component of the decay of an EPR signal attributable to P-680+. The signal IIf rise kinetics also show good agreement with published values of the pH dependence of the decay of P-680+ measured optically (Conjeaud, H. and Mathis, P. (1980) Biochim. Biophys. Acta 590, 353-359). These results are consistent with a model where the species Z (or D1) responsible for Signal IIf is the immediate electron donor to P-680+ in tris-washed Photosystem II fragments.
Original language | English (US) |
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Pages (from-to) | 327-330 |
Number of pages | 4 |
Journal | BBA - Bioenergetics |
Volume | 722 |
Issue number | 2 |
DOIs | |
State | Published - Feb 17 1983 |
Externally published | Yes |
Keywords
- (Spinach chloroplast)
- ESR
- Electron transfer
- P-680
- Photosynthesis
- Photosystem II
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology