Thermotropic behavior of binary mixtures of dipalmitoylphosphatidylcholine and glycosphingolipids in aqueous dispersions.
Thermotropic behavior of binary mixtures of dipalmitoylphosphatidylcholine and glycosphingolipids in aqueous dispersions.
复制标题
二棕榈酰磷脂酰胆碱和鞘糖脂二元混合物在水分散体中的热致行为。
DOI：
10.1016/0005-2736(85)90131-2
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Yu,RK
中科院分区：
文献类型：
--
作者：
Maggio,B;Ariga,T;Sturtevant,JM;Yu,RK
用高灵敏度差示扫描量热法研究了二棕榈酰磷脂酰胆碱(DPPC)与天然鞘糖脂(半乳糖基神经酰胺、磷酸核苷、煤氨酸、葡萄糖神经酰胺、乳糖基神经酰胺、asialo-GM1、硫脂、GM3、GM1、GD1a、GT1b)在整个组成范围内的稀水分散体的热致行为。当糖鞘糖脂的摩尔分数低于0.2时，DPPC的前转变被取消，主转变的协同性急剧下降。所有体系都表现出非理想的温度-组成相图。当糖鞘糖脂在体系中所占比例较高时，单己糖神经酰胺和双己糖神经酰胺很容易与DPPC混溶。有限数量(每分子1-6个DPPC)的鞘糖脂(GSL)可以掺入到均匀混合的脂相中。当DPPC在体系中超过一定比例时，DPPC与GSL-DPPC混合相的其余部分不相容，不显示协同相变，形成DPPC的相区。糖鞘糖脂的寡糖链上的一个负电荷(硫脂)或四个中性碳水化合物残基(asialo-GM1)导致相图显示出在广泛的温度组成范围内凝胶和液体共存。含有神经节苷脂的体系表现出复杂的相图，具有不止一个相变。然而，没有发现纯神经节苷脂物种的相分离结构域的证据。含有DPPC和糖鞘糖脂的体系的热致行为与它们在空气/水界面的混合单层中的相互作用有很好的相关性。
The thermotropic behavior of mixtures of dipalmitoylphosphatidylcholine (DPPC) with natural glycosphingolipids (galactosylceramide, phrenosine, kerasine, glucosylceramide, lactosylceramide, asialo-GM1, sulfatide, GM3, GM1, GD1a, GT1b) in dilute aqueous dispersions were studied by high sensitivity differential scanning calorimetry over the entire composition range. The pretransition of DPPC is abolished and the cooperativity of the main transition decreases sharply at mole fractions of glycosphingolipids below 0.2. All systems exhibit non-ideal temperature-composition phase diagrams. The mono- and di-hexosylceramides are easily miscible with DPPC when the proportion of glycosphingolipids in the system is high. A limited quantity (1–6 molecules of DPPC per molecule of glycosphingolipid (GSL) can be incorporated into a homogeneously mixed lipid phase. Domains of DPPC, immiscible with the rest of a mixed GSL-DPPC phase that shows no cooperative phase transition, are established as DPPC exceeds a certain proportion in the system. One negative charge (sulfatide) or four neutral carbohydrate residues (asialo-GM1) in the oligosaccharide chain of the glycosphingolipids results in phase diagrams exhibiting coexistence of gel and liquid phases over a broad temperature-composition range. Systems containing gangliosides show complex phase diagrams, with more than one phase transition. However, no evidence for phase-separated domains of pure ganglioside species is found. The thermotropic behavior of systems containing DPPC and glycosphingolipids correlates well with their interactions in mixed monolayers at the air/water interface.