Calorimetric studies of the effects of cholesterol on the phase transition of C(18):C(10) phosphatidylcholine

摘要: Differential scanning calorimetry (DSC) has been employed to study the effects of cholesterol on phase transition C(18):C(10) phosphatidylcholine (C(18):C(10)PC). C(18):C(10)PC is an asymmetric mixed-chain known form mixed-interdigitated structures below temperature and partially interdigitated lipid bilayers above transition. Three types samples were used. The treated sample dispersion that had undergone three freeze-thaw cycles stored at 4 degrees C for more than 48 h. untreated was made by vortexing dry in 50 mM KCl, without above-mentioned pretreatment. cold-treated prepared incubating -20 15 d. There no apparent difference DSC curves between samples. data derived from seem be reproducible. cholesterol/C(18):C(10)PC cholesterol/symmetric diacylphosphatidylcholine mixtures are different aspects: overall appearance, dependence delta H, effect maximal Tm, onset To, completion Tc. both samples, total enthalpy change H decreases with increasing content, approaching zero approximately 25 mol%. This level lower changes reported previously mixtures. Both heating cooling thermograms show Tc decrease content. decreasing rates these temperatures neighborhood -0.24 degree per mol% cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)