Effect of the cationic detergent CTAB on the involvement of ADP/ATP antiporter and aspartate/glutamate antiporter in fatty acid-induced uncoupling ofliver mitochondria

The influence of the positively charged amphiphilic compound cetyltrimethyl ammonium bromide (CTAB) on palmitate- and laurate-induced uncoupling and o n carboxyatractylate and glutamate recoupling effects in liver mitochondria have been studied. CTAB (40 muM) in the presence of 3 mM MgCl2 had little (if any) effect on the palmitic acid-stimulated respiration of mitochondria ; the glutamate recoupling effect increased, and the carboxyatractylate rec oupling effect decreased to the same degree with the combined effect (about 80%) remaining unchanged. Thus, CTAB decreases the ADP/ATP antiporter invo lvement and increases to the same extent the aspartate/glutamate antiporter involvement in the fatty acid-induced uncoupling. The carboxyatractylate a nd glutamate recoupling effects were less pH dependent in the presence of C TAB than in its absence. These data could be interpreted with the assumptio n that fatty acid anions are more accessible to the ADP/ATP antiporter and their neutral forms are more accessible to the aspartate/glutamate antiport er, and that CTAB changes the relative anion carrier involvement in the fat ty acid-induced uncoupling as it forms neutral complexes with fatty acid an ions.