A Reevaluation of the Surface Potential of the Inner Mitochondrial Membrane Using ESR Techniques
The basis for the measurement of the surface potential of the inner mitochondrial membrane using electron paramagnetic probes is discussed. The effects of probe permeability in the mitochondrial membrane and the consequences of potential-driven uptake of probe are considered. The problem of probe reduction and destruction is discussed and corrective procedures for this phenomenon are presented. Data are presented on the permeability of the mitochondrial membrane to cationic, amphiphilic spin probes designated Catn. The uptake of these probes is compared to that of a freely permeable phosphonium ion probe. Using this data the repartitioning of the Catn probes upon energization of mitochondria with ATP is explained in terms of changes in surface potential of the inner mitochondrial membrane.
KeywordsMitochondrial Membrane Surface Potential Spin Label Transmembrane Potential Spin Probe
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