Cowman Mary K, Matsuoka Shiro
Othmer Department of Chemical and Biological Sciences and Engineering, Polytechnic University, 6 Metrotech Center, Brooklyn, NY 11201, USA.
Carbohydr Res. 2005 Apr 11;340(5):791-809. doi: 10.1016/j.carres.2005.01.022.
A review of the literature describing experimental studies on hyaluronan (HA) is presented. Methods sensitive to the hydrodynamic properties of HA, analyzed in neutral aqueous solution containing NaCl at physiological concentration, can be shown to fit the expected behavior of a high molecular weight linear semi-flexible polymer. The significant nonideality of HA solutions can be predicted by a simple treatment for hydrodynamic interactions between polymer chains. Nuclear magnetic resonance and circular dichroism studies of HA are also in agreement with a model incorporating dynamically formed and broken hydrogen bonds, contributing to the semi-flexibility of the polymer chain, and segmental motions on the nanosecond time scale. HA shows the capability for self-association in the formation of a viscoelastic putty state at pH 2.5 in the presence of salt, and a gel state at pH 2.5 in mixed organic/aqueous solution containing salt. Ordered and associated structures have also been observed for HA on the surfaces, especially in the presence of surface-structured water. These phenomena can be understood in terms of counterion-mediated polyelectrolyte interactions. The possibility that hyaluronan exists in vivo in environments that induce ordered structures and assemblies is discussed.
本文对描述透明质酸（HA）实验研究的文献进行了综述。在含有生理浓度NaCl的中性水溶液中分析对HA流体动力学性质敏感的方法，可以证明符合高分子量线性半柔性聚合物的预期行为。HA溶液显著的非理想性可以通过对聚合物链间流体动力学相互作用的简单处理来预测。对HA的核磁共振和圆二色性研究也与一个模型相符，该模型包含动态形成和断裂的氢键，这有助于聚合物链的半柔性以及纳秒时间尺度上的片段运动。在有盐存在的情况下，HA在pH 2.5时能自缔合形成粘弹性油灰状状态，在含有盐的有机/水溶液混合体系中，在pH 2.5时能形成凝胶状态。在表面上也观察到了HA的有序和缔合结构，尤其是在存在表面结构化水的情况下。这些现象可以根据反离子介导的聚电解质相互作用来理解。文中还讨论了透明质酸在体内存在于诱导有序结构和组装的环境中的可能性。
