FIGURE 9.

Dehydration facilitates organic cation interaction with the outward facing sites. A, assays were performed as described in the legend to Fig. 3, D–F, but in the presence of 25 mm K⁺/congener, 5 μg of protein (stabilized in the E₂P form, see “Experimental Procedures”), and the indicated concentrations of d-glucose. B, assays were performed in the presence of 2 m glucose, and the indicated concentrations of ions. Open and closed diamonds indicate Cl-Acet⁺-mediated pNPPase activity in the presence or absence of glucose. A representative of four independent measurements is shown.