Cholinergic synaptic vesicles from Torpedo marmorata contain an atractyloside‐binding protein related to the mitochondrial ADP/ATP carrier

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Abstract
Atractyloside is known to bind to the ADP/ATP translocase of the inner mitochondrial membrane, a complex formed by 2 basic protein subunits of relative MW around 30,000. Synaptic vesicles from the electric organ of T. marmorata, which store acetycholine and ATP, bind atracytloside as well. Similarly to mitochondria, a protein-atractyloside complex could be solubilized from vesicle membranes with Triton X-100. Characterization of the complex by gel filtration, isoelectric focusing and gel electrophoresis revealed that atractylsodide was found to protein V11, earlier described as a major vesicle membrane component with a relative MW .apprx. 34,000 and a basic isoelectric point. Since uptake of ATP into isolated vesicles in vitro is inhibited by atractyloside, V11 constitutes the nucleotide carrier of this secretory organelle. The structural and functional relationship of the mitochondrial and vesicular nucleotide translocases suggest a common evolutionary origin.