Xu S, Yamanaka J, Sato S, Miyama I, Yonese M
Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
Chem Pharm Bull (Tokyo). 2000 Jun;48(6):779-83. doi: 10.1248/cpb.48.779.
Complexes composed of sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied to elucidate the exact composition of the complex, the phase separation, the electrophoretic mobility and the size using dynamic light scattering (DLS) and electrophoretic light scattering (ELS), etc. The phase diagram of the mixed solutions was determined. The complexes were soluble in neutral or weakly acidic pH regions and showed phase separation in the more acidic pH region. From the concentration of Na+ released from NaHA when it binds to BSA, the ratios of BSA to NaHA of the complexes were determined. In the region of soluble complexes, one BSA molecule was determined to bind with 15 carboxylic groups of NaHA and in the region of insoluble complexes to bind with 6 carboxylic groups. At the phase separation point, 117 BSA molecules bound with one NaHA molecule and 17% of the carboxylic groups of NaHA did not contribute to the binding of BSA. The sizes of the complexes decreased from several microm to several hundred nm as the binding ratio of BSA increases. Decreases in the viscosities of the mixed solutions were consistent with the decreases of the sizes. From these results, a model of complex formation is proposed.
对由透明质酸钠（NaHA）和牛血清白蛋白（BSA）组成的复合物进行了研究，以使用动态光散射（DLS）和电泳光散射（ELS）等方法阐明复合物的确切组成、相分离、电泳迁移率和尺寸。测定了混合溶液的相图。该复合物在中性或弱酸性pH区域可溶，在酸性更强的pH区域出现相分离。根据NaHA与BSA结合时释放的Na⁺浓度，确定了复合物中BSA与NaHA的比例。在可溶复合物区域，确定一个BSA分子与15个NaHA的羧基结合，在不溶复合物区域与6个羧基结合。在相分离点，117个BSA分子与一个NaHA分子结合，NaHA的17%羧基未参与BSA的结合。随着BSA结合比例的增加，复合物的尺寸从几微米减小到几百纳米。混合溶液粘度的降低与尺寸的减小一致。根据这些结果，提出了复合物形成的模型。
