Figure 4.

Temperature dependence of osmotic water transport in PM- and TP-enriched vesicles. Exponential rate constants (k) of vesicle osmotic shrinking were determined at the indicated temperature (T), as exemplified in Fig. 2. Data were plotted in an Arrhenius representation and activation energy (E_a) values were deduced from the slope of lines fitted by linear regression to the experimental data. For TP (•), mean values from measurements of three independent membrane preparations are shown, and E_a = 2.5 ± 1.3 kcal⋅mol⁻¹. For PM (○ and ▪), data from two individual FFE membrane preparations are shown. ▪, E_a = 12.5 kcal⋅mol⁻¹; ○, for 10³/T ≤ 3.487 K⁻¹ (t ≥ 13.8°C), E_a = 12.0 kcal⋅mol⁻¹; for 10³/T ≥ 3.487 K⁻¹ (t ≤ 13.8°C), E_a = 5.4 kcal⋅mol⁻¹.