Determination of the size of the packing defects in dimyristoylphosphatidylcholine bilayers, present at the phase transition temperature

Abstract

Multilamellar liposomes of dimyristoylphosphatidylcholine, containing 4 mol% egg phosphatidic acid show at the phase transition temperature an increased permeability for non-electrolytes of Mr values up to 900. This indicates that the packing defects occurring at the liquid crystalline/gel state phase boundary have a similar pore diameter (15-18 A) as the packing defects present in glycophorin-dioleoylphosphatidylcholine vesicles. This suggests that packing defects at the protein-lipid interphase are the major permeation pathway of the glycophorin-dioleoylphosphatidylcholine vesicles.