Errington N, Harding S E, Vårum K M, Illum L
University of Nottingham, Department of Applied Biochemistry and Food Science, Sutton Bonington, UK.
Int J Biol Macromol. 1993 Apr;15(2):113-7. doi: 10.1016/0141-8130(93)90008-a.
The molecular weights and gross aqueous solution conformation of two chitosans of different degrees of acetylation, 'Sea Cure +210' (11% acetylated) and KN50 (58% acetylated) were characterized by viscometry, analytical ultracentrifugation and dynamic light scattering. The hydrodynamic parameters obtained were used to determine both the molecular weights and the gross solution conformation of the two chitosans. Using the Wales-Van Holde ratio of sedimentation coefficient concentration regression coefficient (ks) to intrinsic viscosity [eta], the Sea Cure +210 chitosan, which is much less acetylated than the KN50, is highly asymmetric in conformation. This, in conjunction with the charge on the molecule, would suggest a rod-like conformation in solution. The two largest KN50 chitosans have widely differing values for the Wales-Van Holde ratio, suggesting different solution conformation. However, when the series is examined as a whole using the Mark-Houwink-Kuhn-Sakurada relationships relating molecular weight to both intrinsic viscosity and translational diffusion coefficient, then a more spheroidal structure, approximating to a random coil, is predicted.
通过粘度测定法、分析超速离心法和动态光散射法对两种不同乙酰化程度的壳聚糖“Sea Cure +210”（乙酰化程度为11%）和KN50（乙酰化程度为58%）的分子量和粗水溶液构象进行了表征。所获得的流体动力学参数用于确定这两种壳聚糖的分子量和粗溶液构象。利用沉降系数浓度回归系数（ks）与特性粘度[η]的威尔士 - 范霍尔德比值，乙酰化程度远低于KN50的Sea Cure +210壳聚糖在构象上高度不对称。这与分子上的电荷相结合，表明其在溶液中呈棒状构象。两种最大的KN50壳聚糖的威尔士 - 范霍尔德比值差异很大，表明其溶液构象不同。然而，当使用将分子量与特性粘度和平动扩散系数相关联的马克 - 豪温克 - 库恩 - 樱田关系对整个系列进行研究时，则预测其具有更接近无规线团的近似球形结构。
