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Molekulyarnaya Biologiya, vol.13, no.2, pp.324-336, 1979 (Scopus)
In subchloroplast fragments of photosystem II from Vicia faba, free from P700 contamination, a free-radical ESR signal (singlet of 9 G peak-to-peak line-width, g approximately 2,0025) appears under illumination in presence of silicomolybdate as electron acceptor. Using ESR-active electron donors and acceptors as well as conventional redox reagents Hill activity of preparations has been evaluated under different conditions. Evidences are presented that the light-induced dark-reversible silicomolybdate-dependent ESR signal is of the same origin as photobleaching centered at 680 nm which has been earlier interpreted as a result of P680 center of photosystem II oxydation. The relaxation properties of this paramagnetic center as measured by microwave power saturation are different from that of P700+-center in photosystem I.