Preparation of a model system for biological solutions and its industrial applications

制备了两亲性多肽聚（γ -甲基-谷氨酸）-嵌段聚乙二醇（PMLG-PEG）和聚（γ -苄基-谷氨酸）-嵌段聚乙二醇（PBLG-PEG），并研究了它们的聚集结构和增溶行为。这些两亲性多肽可溶于水形成球形聚集体，其中疏水α -螺旋肽尾部以六边形方式有序排列。用半平衡透析（SED）方法表征了平面溶质1-萘酚对这些聚集体的增溶作用。随着聚集体中1-萘酚摩尔分数(X)的增加，增溶平衡常数(K)减小，pblg - peg -1-萘酚体系的增溶等温线高于pmlg - peg -1-萘酚体系。即前者体系中芳香族-芳香族相互作用增强了聚集体与溶质之间的增溶亲合力。因此，肽侧链与溶质之间的相互作用是控制由肽基两亲体组成的胶束聚集体增溶行为的有效因素。因此，我们可以通过肽基有序堆积胶束在水溶液中的选择性增溶行为来证实，这可能是我们血液溶液中含有白蛋白的异常增溶行为的简单模型系统。

Amphiphilic polypeptides, poly( gamma-methyl L-glutamate)-block-poly(ethylene glycol), PMLG-PEG, and poly(gamma -benzyl L-glutamate)-block-poly(ethylene glycol), PBLG-PEG, were prepared and their aggregation structure and solubilization behaviors were investigated. These amphiphilic polypeptides were soluble in water to form spherical aggregates in which the hydrophobic alpha -helical peptide tail was orderly packed in the hexagonal manner. The solubilization of a plane solute, 1-naphthol, into these aggregates was characterized by semi- equilibrium dialysis (SED) method. Values of the solubilization equilibrium constant(K) decrease as the mole fraction of 1-naphthol in the aggregate (X) increases, And the solubilization isotherm of PBLG-PEG-1-naphthol system is higher as compared with that of PMLG-PEG-1-naphthol system. That is, the aromatic-aromatic interaction in the former system may enhance the solubilization affinity between the aggregate and solute. It is shown, therefore, that the interaction between peptide side chains and solutes is the effective factor to control the solubilization behavior of micellar aggregates composed of peptide-based amphiphiles. Thus, we can confirm the selective solubilization behaviors by the peptide- based orderly packed micelles in aqueous solutions, which may be a simple model system of our blood solutions containing albumin for their anomalous solubilization behaviors.