Electrogenic H+/OH- movement across phospholipid vesicles measured by spin-labeled hydrophobic ions

Biophys J. 1983 Oct;44(1):49-57. doi: 10.1016/S0006-3495(83)84276-3.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Electron Spin Resonance Spectroscopy
  • Hydrogen-Ion Concentration*
  • Hydroxides*
  • Liposomes*
  • Mathematics
  • Membrane Potentials
  • Models, Biological

Substances

  • Hydroxides
  • Liposomes