Thermodynamics of charged species transport

The term 6 ms,de v n Equation (7.15) computes the total charge translocated across the membrane for the transport process. Note that since a chemical reaction does not create or destroy charge, 

Applying Equation (7.15) to isothermal isobaric transport, we have the following equation for the Gibbs free energy for the coupled chemical reaction and transport 

The ratio ([ATP4-]/[ADP3-]) in the matrix is typically on the order of 1 and may be as low as 0.2, while in the cytoplasm and in the intermembrane space the ratio is approximately 50. The membrane potential in respiring mitochondria is approximately 160 mV. Under these conditions the free energy of the ANT exchanger is computed 

Thus under typical conditions the concentration free energy barrier of 5.52 RT is overcome by an electrostatic driving force of 5.98 RT. 

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