An analysis of the binding of fluorescence probes in mitochondrial systems.

Measurements of the binding of the fluorescent probes 8-anilinonaphthalene-1-sulfonate (ANS) and ethidium ions to whole and disruped mitochondria and submitochondrial particles suggest that the inner mitochondrial membrane is freely permeable to the two probes. Equations relating the binding of permeant probes to the electro-chemical balance across the membrane of vesicular systems are derived and these equations used to analyze Scatchard plots of the binding of the two probes to energized and nonenergized mitochondria and EDTA particles.