Table 3 Composition of external solutions for the simultaneous generation of membrane potential and pH gradient as driving forces for the uptake of L-glutamate or D-lactose

From: Chemiosmotic nutrient transport in synthetic cells powered by electrogenic antiport coupled to decarboxylation

External component*

ZΔpH (mV)** ≈ −30

ΔΨ (mV) = 0 (no valinomycin)

ZΔpH (mV) ≈ −30

ΔΨ (mV) = −25

ZΔpH (mV) ≈ −30

ΔΨ (mV) = −53

ZΔpH (mV) ≈ −30

ΔΨ (mV) = −75

ZΔpH (mV) ≈ 30

ΔΨ (mV) = −103

Na-acetate (mM)

22

22

22

22

22

Na-D-gluconate (mM)

48

8

36

44

48

K-D-gluconate (mM)

0

40

12

4

0

[K+]o***

2.2

42.2

14.2

6.2

2.2

  1. *In addition to 2 mM sodium-L-lactate, 25 mM sodium phosphate pH 7.0, the radiolabelled substrate with/without 1 µM valinomycin. ** With this gradient of acetate, the ΔpH ≈ 0.5. ***Calculated from the addition of potassium-D-gluconate plus K+ contribution from the dilution of proteoliposomes in external solution (2.2 mM).
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