摘要
用差示扫描量热研究了金属离子和稀土配合物对二棕榈酰磷脂酸乙醇胺(DPPE)脂双层由凝胶态向液晶态相转变的温度T_m的影响 发现加入金属离子提高了DPPE脂双层的相转变温度.其中,Na^+<Ca^(2+)<Ln^(3+).Pr^(3+)的影响较La^(3-)强.在pH7.4时,柠檬酸钠对T_m影响很小,相反在pH2.0时,则降低相变温度T_m.乳酸稀土在pH2.0和pH7.4时都显著提高T_m,在中性条件下,对T_m影响更大.同时,乳酸稀土较相同浓度下的稀土离子影响大,说明乳酸稀土中稀土离子和乳酸根配体存在协同作用.我们初步探讨了金属离子以及稀土配合物对DPPE脂双层相变温度影响的原因.
The effects of metal ions and lanthanide complexes on the gel-to-liquid crystal phase transition temperature Tm of dipalmitoylphosphatidylethanolamine liposomes have been studied by differential scanning calorimetry (DSC) method. The results show that the addition of metal ions to the dipalmitoylphosphatidylethanolamine (DPPE) liposomes dispersions increases the main phase transition temperature Tm in the order of monovalent< divalent <trivalent cations. The enhancement of Tm is not large as increasing the lanthanide ions concentration. The enhancement of Pr3+ is larger than that of La3+. Remarkable differences were observed between La-citrate and La-lactate complexes at different pH solutions. At pH 7.0, La-citrate complex has no effect on the Tm, La-lactate complex, however, increases the Tm value, and the increase is larger than that of free lanthanide ions at the same concentration. The decrease of pH of complexes solutions lowers the phase transition temperature. We have preliminarily discussed the mechanism of the enhancements of lanthanide ions and the synergism of lanthanide ion and lactate ligand follow the ion induced dehydration of lipid and the potential effects of ion-lipid interaction.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1995年第4期353-356,共4页
Acta Chimica Sinica
基金
国家攀登计划"稀土基础研究"资助的项目.
