Repeatability Flash Profile

Flash-induced proton uptake by RCs of Rb. sphaeroides, strain Ga, in the presence of ferrocene, was measured at various pH, at a salt concentration of 50 mM KCl (Fig. 3A). The proton uptake induced by the first flash is less than that induced by the second at all pH less than 9.5, and this pattern of odd versus even flashes is repeated in a longer series of flashes. The pH profile of proton uptake on the first flash is characterized by two main maxima - at pH 5 and 10, and a smaller additional maximum at pH 6.5 (Fig. 3B, and ref. 8). At the two main peaks approximately 0.7 and 1 proton per P+ is taken up. 

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