Energy Transduction in Mitochondrial Fragments

Atebrin and acridine orange fluorescence and absorbance characteristics are sensitive to their environment. Anions, such as iodide, nitrate or chloride strongly decrease acridines fluorescence, while sulfate or acetate are much less effective. Energization by succinate or ATP of rat liver mitochondrial fragments produces a fluorescence decrease of atebrin, only in the presence of iodide, nitrate or chloride. In the presence of sulfate or acetate or in the absence of anions, no changes are detected. Binding changes of acridines are also observed in association with energy conservation in mitochondrial fragments in the presence of iodide, nitrate or chloride. These data are consistent with a model in which the membrane of mitochondrial fragments, becoming more positive than the medium when energized, creates local electrolyte concentration changes affecting fluorescence, absorbance and binding properties of acridine dyes.