Effect of the Cationic Detergent CTAB on the Involvement of ADP/ATP Antiporter and Aspartate/Glutamate Antiporter in Fatty Acid-Induced Uncoupling of Liver Mitochondria

V. N. Samartsev^1,2, O. V. Markova¹, S. A. Chezghanova², and E. N. Mokhova^1*

¹Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-0338; E-mail: mokhova@genebee.msu.su

²Mari State University, pl. Lenina 1, Yoshkar-Ola, 4221001 Russia; fax: (836-2) 45-4581

^* To whom correspondence should be addressed.

Received January 29, 2001; Revision received April 6, 2001

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The influence of the positively charged amphiphilic compound cetyltrimethyl ammonium bromide (CTAB) on palmitate- and laurate-induced uncoupling and on carboxyatractylate and glutamate recoupling effects in liver mitochondria have been studied. CTAB (40 µM) 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 recoupling effect decreased to the same degree with the combined effect (about 80%) remaining unchanged. Thus, CTAB decreases the ADP/ATP antiporter involvement and increases to the same extent the aspartate/glutamate antiporter involvement in the fatty acid-induced uncoupling. The carboxyatractylate and glutamate recoupling effects were less pH dependent in the presence of CTAB than in its absence. These data could be interpreted with the assumption that fatty acid anions are more accessible to the ADP/ATP antiporter and their neutral forms are more accessible to the aspartate/glutamate antiporter, and that CTAB changes the relative anion carrier involvement in the fatty acid-induced uncoupling as it forms neutral complexes with fatty acid anions.

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KEY WORDS: uncoupling, fatty acids, glutamate, carboxyatractylate, aspartate/glutamate antiporter, ADP/ATP antiporter, CTAB, liver mitochondria

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