Membrane:buffer partition coefficient for ethanol in dimyristoylphosphatidylcholine.

Phase transitions of dimyristoylphosphatidylcholine (DMPC) are followed using optical density measurements, as a function of aqueous ethanol concentration. The shift of the phase transition to lower temperatures is interpreted in terms of the thermodynamics of freezing point depressions. This analysis provides a partition coefficient of ethanol into DMPC of 0.07 liter of solution/kg membrane or 2.64 moles of solvent/mole of DMPC.