Effect of 1-palmitoyl lysophosphatidylcholine on phase properties of 1,2-dipalmitoyl phosphatidylethanolamine: a thermodynamic and NMR study

摘要: Abstract The effect of 1-palmitoyl lysophosphatidylcholine (PLPC) on the phase behaviour 1,2-dipalmitoyl phosphatidylethanolamine (DPPE) in excess water (34 wt%) has been examined by differential scanning calorimetry, dilatometry and isothermal compressibility measurements. Mole percentages PLPC DPPE between 14 62% have studied over temperature range 30–75°C. dependence orientational ordering at selected sites 2 H-labelled H O determined from measurement time-averaged chemical shift anisotropies quadrupole splittings 31 P- H-NMR spectra. These data used to further characterize behaviour. At less than equimolar contents PLPC, when a single transition with reduced is observed, spectral calorimetric indicate complete miscibility two lipid components. An mixture shows sharp first order 47.3°C second 62.5°C. NMR are consistent existence defective bilayer intermediary temperatures. In this it proposed that molecules prefer regions high curvature vicinity defects, while mostly confined flatter bilayer. A possible molecular model described. temperatures above 62.5°C, completely miscible exist as lamellae. higher content (> 50 mol%), thermodynamic indicative separation components examined.