THE NATURE AND REGULATION OF THE ATP-INDUCED ANION PERMEABILITY IN SACCHAROMYCES-CEREVISIAE MITOCHONDRIA

ATP lowers the efficiency of oxidative phosphorylation in Saccharomyce s cerevisiae mitochondria by a mechanism that involves the activation of cytochrome c oxidase and the increase in anion permeability of the mitochondrial inner membrane (S. Prieto, F. Bouillaud, and E. Rial (19 95) Biochem. J. 307, 657-661). In this study, we have carried out expe riments to determine the transport specificity of the ATP-induced perm eability pathway and its regulation. The pathway allows permeation of anions such as Cl- or Br-, while NO3-, NO2-, or Tes are not transporte d. Transport is activated by ATP, GTP, dATP, dGTP, and GDP, while ADP, AMP, GMP, and pyrimidine nucleotides are ineffective. Analysis of tra nsport inhibition by ADP and phosphate suggests that ADP is a competit ive inhibitor of ATP while phosphate inhibition is noncompetitive. The se effecters are operative in the physiological range of concentration s. (C) 1996 Academic Press, Inc.