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FLASH PHOTOLYSIS‐ELECTRON SPIN RESONANCE STUDIES OF THE DYNAMICS OF PHOTOSYSTEM I IN GREEN‐PLANT PHOTOSYNTHESIS—II. INTACT AND BROKEN SPINACH CHLOROPLASTS *
Author(s) -
Warden Joseph T.,
Bolton James R.
Publication year - 1974
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1974.tb06576.x
Subject(s) - p700 , photosystem i , dcmu , flash photolysis , photochemistry , chemistry , photosystem ii , electron paramagnetic resonance , electron acceptor , electron transfer , photosynthesis , chloroplast , light harvesting complexes of green plants , ultrafast laser spectroscopy , electron donor , kinetics , spectroscopy , nuclear magnetic resonance , reaction rate constant , physics , biochemistry , quantum mechanics , gene , catalysis
—The transient oxidation and subsequent reduction of P700 + in spinach chloroplasts has been monitored by flash photolysis‐electron spin resonance spectroscopy in the presence of various donors and acceptors. In general, the results obtained correlate well with results on Photosystem I subchloroplast particles, with two major differences. For Type A and B intact chloroplasts in the presence of 3‐(3, 4‐dichlorophenyl)‐1, 1‐dimethylurea (DCMU), the electron acceptor methyl viologen has no effect on the decay kinetics. This phenomenon is interpreted in terms of a functioning cyclic electron flow path around Photosystem I. Also, the photoresponse of Signal I depends on the length of the photolyzing flash. This is interpreted in terms of the existence of a primary electron donor to P700 + with a transfer time of ˜ 10 μs.