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标题：Interaction of long-chain nicotinates with dipalmitoylphosphatidylcholine
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作者：Hans-Joachim Lehmler ; Azarih Fortis-Santiago ; Dhananjaya Nauduri 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2005
卷号：46
期号：03
页码：535-546
DOI：10.1194/jlr.M400406-JLR200
出版社：American Society for Biochemistry and Molecular Biology
摘要：The interaction of four long-chain nicotinates, compounds that are of interest as potential chemopreventive agents, with dipalmitoylphosphatidylcholine (DPPC) was investigated in monolayers at the air-water interface and in fully hydrated bilayers. For the monolayer studies, the compression isotherms of mixtures of the respective nicotinate with DPPC were recorded at various compositions on a hydrochloric acid subphase (pH 1.9–2.1, 37 ± 2°C). The headgroup of the nicotinates (24–29 Å2/molecule) is larger than that of the hydrophobic tail (20 Å2/molecule). The pure nicotinates exhibit a temperature- and chain length-dependent transition from an expanded to a condensed phase. Analysis of the concentration dependence of the average molecular area at constant film pressure and the concentration dependence of the breakpoint of the phase transition from the expanded to the condensed state suggests that all four DPPC-nicotinate mixtures are partially miscible at the air-water interface. Although a complex phase behavior with several phase transitions was observed, differential scanning calorimetry studies of the four mixtures are also indicative of the partial miscibility of DPPC and the respective nicotinate. Overall, the complex phase behavior most likely results from the head-tail mismatch of the nicotinates and the geometric packing constraints in the two-component lipid bilayer.
关键词：differential scanning calorimetry • Langmuir monolayer • liposomes • lipid phase transition • head-tail mismatch