THE ATP-INDUCED K-TRANSPORT PATHWAY OF YEAST MITOCHONDRIA MAY FUNCTION AS AN UNCOUPLING PATHWAY()

The effect of the presence of K+ during oxidative phosphorylation meas ured on isolated yeast mitochondria was dependent on phosphate concent ration. At 0.5 mM phosphate, K+ did promote an uncoupling of oxidative phosphorylation, which was prevented by decavanadate, a potent inhibi tor of the ATP-induced K+-transport pathway. At 5 mM phosphate, no unc oupling effect of K+ could be evidenced. These data suggest that the A TP-induced K+-transport pathway may, under certain conditions, functio n as an uncoupling pathway of oxidative phosphorylation.