The Mitochondrial Outer Membrane Contains at Least Two Distinct Channels
The presence in the mitochondrial outer membrane of a cationic channel blocked by a 13 residue addressing peptide had been shown by the technique of “tip-dip”. This channel was studied in planar bilayers and compared to the anionic porin, the voltage-dependent anion channel, observed in the same conditions. The two activities were clearly different. The peptide sensitive channel, present in both wild type and porin-deficient mutant yeast, is not a rescue channel, but an alternate independent permeability pathway. The channel interacted more strongly with a longer extension of the addressing peptide containing 22 residues, suggesting a physiological interaction of this type of molecule with the cationic channel.
KeywordsPermeability Glycerol Fractionation Trypsin Cytosol
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