Electron transport reactions in grana preparations from spinach chloroplasts.
Fraction 2 (grana-stack) particles prepared with the French press showed absorbance changes, at room temperature and with sodium ascorbate and methyl-viologen, that were produced by the oxidation of cytochrome b-559. This oxidation was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and sensitized by system II of photosynthesis. The oxidation is too slow to account for the rates of the Hill reaction that have been observed with nicotinamide-adenine dinucleotide phosphate (NADP(+)). It appears that this cytochrome is not functioning in the main pathway of electron transport. In the presence of 2,3,5,6-tetramethyl-p-phenylene-diamine (DAD) and ascorbate, light-induced oxidation of cytochrome f took place within 3 msec (or faster) in the grana-stack particles. Treatment with the detergent Triton X-100 disrupted this rapid cytochrome f oxidation as well as the oxidation of cytochrome b-559. Subsequent plastocyanin addition did not restore the rapid oxidation of cytochrome f (nor of cytochrome b-559) but only slow changes of cytochrome f. In view of the fact that these particles contain almost no plastocyanin, it is unlikely that plastocyanin functions in electron transport between cytochrome f and P-700 in the particles derived from the grana-stack regions of the chloroplast.
D000814:Aniline Compounds / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D002736:Chloroplasts / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism; D004237:Diuron / Q000494:pharmacology; D004579:Electron Transport; D007700:Kinetics; D010940:Plant Proteins / Q000378:metabolism; D010945:Plants, Edible / Q000166:cytology; D011726:Pyridinium Compounds / Q000494:pharmacology; D013057:Spectrum Analysis; D013501:Surface-Active Agents / Q000494:pharmacology
D000814:Aniline Compounds; D003580:Cytochromes; D010940:Plant Proteins; D011726:Pyridinium Compounds; D013501:Surface-Active Agents; D004237:Diuron; D001205:Ascorbic Acid