The pH-dependent reciprocal changes in contributions of ADP/ATP antiporter and aspartate/glutamate antiporter to the fatty acid-induced uncoupling

The pH effect on carboxyatractylate-, glutamate- and aspartate-induced recoupling of palmitate-uncoupled rat liver mitochondria has been studied. Stimulation of respiration by low palmitate concentrations (5–20 μM) in the presence of 3 mM MgCl2 is shown to be pH-independent within the 7.0–7.8 range. The recoupling effect of glutamate (or aspartate) decreases and that of carboxyatractylate increases with increase in pH. The recoupling effect of a combination of carboxyatractylate and glutamate (aspartate) appears to be constant at these pH values, being as high as about 80%. It is concluded that uncoupling by low palmitate in liver mitochondria is mediated mainly by ATP/ADP and aspartate/glutamate antiporter.