脂肽的自组装特性及其与十二烷基麦芽糖苷的复配研究

Self-Assemble Characteristics of Lipopeptide and Its Complex with n-Dodecyl-β-D-Maltoside

以组氨酸和十二烷酸为原料,合成了3种脂肽C_(12)HH-COOH、C_(12)HH-CONH_2和C_(12)HHH-CONH_2,该类脂肽分子结构中都包含十二烷酸疏水烷烃链及组氨酸亲水肽链,具有传统表面活性剂和肽表面活性剂的结构特点。表面张力分析表明,3种脂肽在水溶液中都具有明显的表面活性剂特性,在MES缓冲溶液(20mmol·L^(-1),pH=6.0)中的临界胶束浓度分别为0.40mmol·L^(-1)、0.63mmol·L^(-1)、1.10mmol·L^(-1);随着缓冲溶液pH值的减小,脂肽亲水头基组氨酸侧链的带电性增强,临界胶束浓度逐渐增大。3种脂肽都能与传统表面活性剂十二烷基麦芽糖苷(DDM)复配自组装形成混合胶束,且混合胶束的平均粒径与复配体系中脂肽的含量有关。

Using histidine and dodecanoic acid as raw materials,we synthesized three lipopeptides C12 HH- COOH,C12 HH-CONH2 ,and C12 HHH-CONH2. Molecular structures of such lipopeptides contain dodecanoic acid hydrophobic alkane chain and histidine hydrophilic peptide chain, therefore they have the structural features of traditional surfactants and peptide surfactants. The surface tension analysis indicated that,three lipopeptides exhibited significant surfactant properties in aqueous solution,and the critical micelle concentrations（CMC） in MES buffer solution（20 mmol · L^-1,pH=6. 0） were 0.40 mmol · L^-1 ,0.63 mmol · L^-1 ,and 1. 10 mmol· L^-1 ,respectively. As the pH value of MES buffer solution decreased, the chargeability of the hydrophilic head group histidine side chain and the CMC increased. Three lipopeptides were able to form mixed micelles by self- assembly with the traditional surfactant n-dodecyl-β-D-maltoside（DDM）,and the average particle size of mixed micelles was related to the lipopeptide content of complex system.