FATTY-ACIDS INDUCED UNCOUPLING OF SACCHAROMYCES-CEREVISIAE MITOCHONDRIA REQUIRES AN INTACT ADP ATP CARRIER/

Fatty acids stimulate the oxidation rate of mitochondria isolated from the wild-type Saccharomyces cerevisiae, but do not affect significant ly the respiration of mitochondria isolated from mutants, in which the ADP/ATP carrier (AAC) was either modified (R96H) or deleted (Delta aa c2). Similarly as in mammalian mitochondria, the transmembrane electri cal potential difference (Delta psi) in the wild-type yeast mitochondr ia was dissipated by low concentrations of free fatty acids, and this was partially inhibited by bongkrecate, In contrast to the wild-type m itochondria, the addition of increasing concentrations of fatty acids to the op1 (R96H) mutant mitochondria abolished only a small portion o f Delta psi, as compared to the change induced by classical uncouplers , The different effects of fatty acids on both, the respiration and th e Delta psi of mitochondria isolated from the wild-type and the aac mu tants, respectively, demonstrates that the intact AAC is essential for the fatty acids induced H+ permeability of mitochondrial membrane. (C ) 1997 Federation of European Biochemical Societies.