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 stu died, Stimulation of respiration by low palmitate concentrations (5-20 mu M) in the presence of 3 mM MgCl2 is shown to be pH-independent wit hin the 7.0-7.8 range. The recoupling effect of glutamate (or aspartat e) decreases and that of carboxyatractylate increases,vith 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 palmitat e in liver mitochondria is mediated mainly by ATP/ADP and aspartate/gl utamate antiporter. (C) 1997 Federation of European Biochemical Societ ies.