Nonelectrolyte substitution for water in phosphatidylcholine bilayers

Glycerol substitutes for water in multilamellar phosphatidylcholine liposomes in that the fluid spaces between bilayers, as well as their main transition temperatures, heat capacities, and ethalpies are very similar in water and in pure glycerol. One major difference is that the gel state phase of dipalmitoylphosphatidylcholine (DPPC) in glycerol consists of bilayers with fully interdigitated hydrocarbon chains. Interdigitated DPPC phases are also formed in ethylene glycol or in methanol (at low methanol content). In solutions of glycerol and water, the fluid spacing between bilayers is a function of mole fraction of glycerol Xg, reaching maximum values at Xg {all equal to} 0.1 for lipid in the liquid crystalline phase and at Xg {all equal to} 0.3 for the gel phase. These changes are explained in terms of a modification of the long-range Van der Waals attractive forces by glycerol. © 1983.

Duke Scholars

Author Thomas James McIntosh Cell Biology

Author Sidney Arthur Simon Neurobiology