Fatty acids induced uncoupling ofSaccharomyces cerevisiaemitochondria requires an intact ADP/ATP carrier

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Abstract
Fatty acids stimulate the oxidation rate of mitochondria isolated from the wild‐type Saccharomyces cerevisiae, but do not affect significantly the respiration of mitochondria isolated from mutants, in which the ADP/ATP carrier (AAC) was either modified (R96H) or deleted (Δaac2). Similarly as in mammalian mitochondria, the transmembrane electrical potential difference (Δψ) in the wild‐type yeast mitochondria was dissipated by low concentrations of free fatty acids, and this was partially inhibited by bongkrecate. In contrast to the wild‐type mitochondria, the addition of increasing concentrations of fatty acids to the op1 (R96H) mutant mitochondria abolished only a small portion of Δψ, as compared to the change induced by classical uncouplers. The different effects of fatty acids on both, the respiration and the Δψ of mitochondria isolated from the wild‐type and the aac mutants, respectively, demonstrates that the intact AAC is essential for the fatty acids induced H+ permeability of mitochondrial membrane.