Guetta O, Milas M, Rinaudo M
Centre de Recherche sur les Macromolécules Végétales, CNRS, associated with Joseph Fourier University, BP 53, 38041 Grenoble Cedex 9, France.
Biomacromolecules. 2003 Sep-Oct;4(5):1372-9. doi: 10.1021/bm030036u.
The chemical structure and the rheological behavior of the Klebsiella polysaccharide ATCC 12657 was studied and compared with data described in the literature and obtained for similar polysaccharides. The acetylated polysaccharide presents in solution a normal viscoelastic behavior with no evidence of an ordered conformation whatever the experimental conditions are. The deacetylated form can induce the formation of physical gels, in the presence of salt excess or ethanol. Microcalorimetry, optical rotation, and rheology experiments demonstrate that a thermally reversible and highly cooperative conformational transition occurs at the same temperature than a sol-gel transition. The melting of the gel and the conformational transition temperatures are dependent on the nature of cations and ionic concentration, whereas the gel strength is only influenced by polymer concentration.
对肺炎克雷伯菌多糖ATCC 12657的化学结构和流变行为进行了研究，并与文献中描述的以及类似多糖的数据进行了比较。无论实验条件如何，乙酰化多糖在溶液中呈现出正常的粘弹性行为，没有有序构象的证据。在存在过量盐或乙醇的情况下，脱乙酰化形式可诱导物理凝胶的形成。微量量热法、旋光法和流变学实验表明，在与溶胶-凝胶转变相同的温度下发生热可逆且高度协同的构象转变。凝胶的熔化温度和构象转变温度取决于阳离子的性质和离子浓度，而凝胶强度仅受聚合物浓度的影响。
