Ruggiero J, Vieira R P, Mourão P A
Departamento de Física, Universidade Estadual Julio de Mesquita Filho, São José do Rio Preto, Brazil.
Carbohydr Res. 1994 Apr 1;256(2):275-87. doi: 10.1016/0008-6215(94)84213-2.
Calcium binding and charge distribution on a fucosylated chondroitin sulfate and a standard chondroitin 6-sulfate have been studied using a metallochromic indicator and conductimetric titrations. The fucosylated chondroitin sulfate has a approximately 5-fold greater affinity for calcium ions than the standard chondroitin 6-sulfate. Possibly, this increased affinity for calcium ions is due to the branches on the fucosylated chondroitin sulfate, since the calcium affinity of an unbranched, sulfated fucan is similar to that of the standard chondroitin 6-sulfate. More charged groups per disaccharide unit (and a shorter distance between these groups) also distinguish the fucosylated chondroitin sulfate from standard chondroitin 6-sulfate. Comparison between native and chemically modified (desulfated or carboxyl-reduced) polysaccharides suggests that the sulfate esters are responsible for the increased charge density of the fucosylated chondroitin sulfate and that the presence of the fucose branches does not alter the length of the repetitive units which compose the central core of chondroitin from sea cucumber. These results are consistent with the chemical studies of these two polysaccharides.
利用金属显色指示剂和电导滴定法，对岩藻糖基化硫酸软骨素和标准硫酸软骨素6-硫酸酯上的钙结合及电荷分布进行了研究。岩藻糖基化硫酸软骨素对钙离子的亲和力比标准硫酸软骨素6-硫酸酯高约5倍。这种对钙离子亲和力的增加可能是由于岩藻糖基化硫酸软骨素上的分支，因为未分支的硫酸化岩藻聚糖对钙的亲和力与标准硫酸软骨素6-硫酸酯相似。每个二糖单元更多的带电基团（以及这些基团之间较短的距离）也使岩藻糖基化硫酸软骨素与标准硫酸软骨素6-硫酸酯有所区别。天然多糖与化学修饰（脱硫酸或羧基还原）多糖之间的比较表明，硫酸酯导致了岩藻糖基化硫酸软骨素电荷密度的增加，并且岩藻糖分支的存在不会改变构成海参软骨素中心核心的重复单元的长度。这些结果与这两种多糖的化学研究结果一致。
