Effect of Leader Peptides on the Permeability of Mitochondria

Peptides with sequences based on the leader sequence of yeast cytochrome c oxidase subunit IV (pCOX IV-(1–25)) activate the electrophoretic uptake of K+ and other cations such as tetraethylammonium and lysine by rat liver mitochondria with EC50 = 11–15 μm. Uptake of these cations is dependent on respiration and is prevented by uncoupling agents, and the Vmax for K+ is 1.2–1.5 μmol/min/mg. Albeit more slowly, the non-electrolytes mannitol and...