EVIDENCE FOR 3 DIFFERENT ELECTROPHORETIC PATHWAYS IN YEAST MITOCHONDRIA - ION SPECIFICITY AND INHIBITOR SENSITIVITY

We identified three electrophoretic pathways by spectrophotometrically following the swelling of isolated yeast mitochondria: An anion unipo rt whose activity could only be detected after depletion of divalent c ations from the matrix by treatment with 1,10-phenanthroline. This uni port was inhibited by Mg2+ and dicyclohexylcarbodiimide. AK(+)(Na-) un iport which was detected only when mitochondria were suspended at low pH and low temperature. This uniport was sensitive to ruthenium red an d oleic acid. AK(+) selective uniport which was activated by alkaline pH and ATP depletion. This pathway was sensitive to glibenclamide and to various amphiphilic cations. Similarities and differences between t hese three electrophoretic pathways and the electrophoretic systems de scribed in mammalian and plant mitochondria are discussed.