Effect of pH, mono- and divalent cations on the mixing of phosphatidylglycerol with phosphatidylcholine. A monolayer (π, ΔV) and fluorescence study

摘要: Abstract The mixing of various molecular species phosphatidylglycerol and phosphatidylcholine differing in their acyl chain lengths has been studied both monolayers (π, Δ V ), water dispersions (fluorescence polarization) with varying pH ionic strength the aqueous phase presence divalent cations Mg2+ Ca2+. In dilauroylphosphatidylglycerol/dipalmitoylphosphatidylcholine mixtures, dispersions, no separation was detected at 2.9 where protonated. With dipalmitoylphosphatidylglycerol/dipalmitoylphosphatidylcholine same pH, for surface pressures below π = 40 mN · m −1 . monolayers, under conditions such that ionized (pH 5.6, 10 mM NaCl) miscibility observed dilauroylphosphatidylglycerol dipalmitoylphosphatidylcholine also dipalmitoylphosphatidylglycerol dilauroylphosphatidylcholine. Varying did not alter these lipids. Ca2+ modify dilauroylphosphatidylcholine or dipalmitoylphosphatidylcholine. Both appeared to be least partly miscible, magnesium. Only calcium high pressure might monolayer data account between two presented demonstrate existence strong cohesive forces a marked influence former on physical state latter. From an analysis data, it is suggested intrafacial hydrogen bonds may play significant role stabilizing phosphatidylcholine/phosphatidylglycerol mixtures.