Electrogenic H+/OH- movement across phospholipid vesicles measured by spin-labeled hydrophobic ions.
Transmembrane pH gradients created across phospholipid vesicles give rise to time-dependent potentials as determined from the EPR spectra of phosphonium ion spin labels in the system. From the time-dependent spectra, the transmembrane H+/OH- current is obtained and hence the current-voltage curve for the vesicle membrane is obtained. The current-voltage curve is linear with a membrane resistance of 3 +/- 2 X 10(9) omega cm2 corresponding to a membrane permeability of 5 +/- 2 X 10(-7) cm/s. This unusually high permeability is further increased by small amounts of lipid oxidation, CHCl3 or the general anesthetic halothane.
D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides; D008081:Liposomes; D008433:Mathematics; D008564:Membrane Potentials; D008954:Models, Biological
D006878:Hydroxides; D008081:Liposomes