FIG. 4.

Dependence of succinate transport on succinate concentration at different pH values. The initial uptake of [¹⁴C]succinate by succinate-grown cells of P. lemoignei was measured at different pH values and at different succinate concentrations. The rates of succinate transport were calculated from the slopes (not shown) and were plotted against the succinate concentration. The insets provide the values for the micromolar concentration range and give the slopes of the graphs as follows: [nanomoles/(minute × milligram of protein)/micromolar concentration of succinate]. Please note the different scales in the insets in panels A to C and D to E, respectively. The experiments were performed at pH 5.6 (A), pH 6.2 (B), pH 6.5 (C), pH 6.8 (D), pH 7.2 (E), and pH 7.6 (F).