INHIBITION OF THE MITOCHONDRIAL CYCLOSPORINE A-SENSITIVE PERMEABILITYTRANSITION PORE BY THE ARGININE REAGENT PHENYLGLYOXAL

The mitochondrial permeability transition pore, a cyclosporin A-sensit ive channel, is controlled by the transmembrane electric potential dif ference across the inner membrane, Here, we show that treatment of rat liver mitochondria with the arginine reagent phenylglyoxal inhibits t he permeability transition pore triggered by depolarization with uncou pler after Ca2+ accumulation, Phenglglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization , indicating that covalent modification of arginine (and possibly lysi ne) residues directly affects the open probability of the pore, We pro pose that arginine residues play a role in the physiological control o f the permeability transition pore by the mitochondrial transmembrane potential. (C) 1997 Federation of European Biochemical Societies.