Figure 4.  Transport systems coupled to .  The data shown are for lactose accumu衍ation by RSO vesicles con負aining the lactose permease, but similar profiles are observed for proline, serine, glycine, tyro貞ine, glutamic acid, lysine, leucine, cysteine and succinate (a dicarboxylic acid).  At pH 5.5, accumulation of each of these substrates is relatively mildly inhibited by both valinomycin and nigericin, while at pH 7.5, valinomycin becomes a potent inhibitor and nigericin has no effect.  The profiles  resemble that observed for the total driving force () in Fig. 3.