FATTY ACID-MEDIATED UNCOUPLING OF POTATO-TUBER MITOCHONDRIA

The present work examined whether the ATP/ADP carrier, other than the plant uncoupling mitochondrial protein, participates in free fatty aci d-mediated uncoupling of potato tuber mitochondria. The basal respirat ion rate of succinate-energized mitochondria was stimulated by a low c oncentration of palmitate (20 mu M). This uncoupling was reversed by 1 0 mu M carboxyatractyloside and by the subsequent addition of 0.1% bov ine serum albumin. The decrease in membrane potential caused by palmit ate was suppressed by carboxyatractyloside (1 mu M) and, to a lesser d egree, by bongkrekate (20 mu M). GTP could also reversed this decrease via a carboxyatractyloside-independent mechanism. These results indic ate that the ATP/ADP carrier, along with the plant uncoupling mitochon drial protein, participates in the protonophoric action of palmitate i n potato tuber mitochondria.