Electrostatic interactions among hydrophobic ions in lipid bilayer membranes.
We have shown that the absorption of tetraphenylborate into black lipid membranes formed from either bacterial phosphatidylethanolamine or glycerolmonooleate produces concentration-dependent changes in the electrostatic potential between the membrane interior and the bulk aqueous phases. These potential changes were studied by a variety of techniques: voltage clamp, charge pulse, and "probe" measurements on black lipid membranes; electrophroetic mobility measurements on phospholipid vesicles; and surface potential measurements on phospholipid monolayers. The magnitude of the potential changes indicates that tetraphenylborate absorbs into a region of the membrane with a low dielectric constant, where it produces substantial boundary potentials, as first suggested by Markin et al. (1971). Many features of our data can be explained by a simple three-capacitor model, which we develop in a self-consistent manner. Some discrepancies between our data and the simple model suggest that discrete charge phenomena may be important within these thin membranes.
D001419:Bacteria; D001896:Boron Compounds; D004563:Electrochemistry; D005990:Glycerol; D007477:Ions; D007700:Kinetics; D008567:Membranes, Artificial; D008954:Models, Biological; D009829:Oleic Acids; D010714:Phosphatidylethanolamines; D011199:Potentiometry; D013775:Tetraphenylborate
D001896:Boron Compounds; D007477:Ions; D008567:Membranes, Artificial; D009829:Oleic Acids; D010714:Phosphatidylethanolamines; D013775:Tetraphenylborate; D005990:Glycerol