Volpi Nicola
Department of Animal Biology, Biological Chemistry, University of Modena and Reggio Emilia, Italy.
Biomaterials. 2002 Jul;23(14):3015-22. doi: 10.1016/s0142-9612(02)00060-1.
The adsorption of chondroitin sulfate onto granules of natural coral of specific diameter, between 100 and 500 microm, having high calcium content (> 98%) and a homogeneous surface was investigated. Several chondroitin sulfate samples desulfated to various extents, with a sulfate to disaccharide ratio (charge density) of 0.98-0.07 and non-sulfated polysaccharide possessing a chondroitin sulfate backbone structure were tested for their ability to adsorb onto coral. Adsorption of chondroitin sulfate onto coral depends on its charge density, as the removal of sulfate groups totally abolishes this capacity. Various chondroitin sulfates of molecular mass from 26,950 to 1140 were also tested. No appreciable effect depending on the molecular mass was evident. Also, chondroitin sulfate fractions with molecular mass of about 3530 (formed by about 6 disaccharide units) and 1140 (formed by about 2 disaccharide units) retain their full capacity to adsorb onto coral. Furthermore, the position of sulfate groups inside the polysaccharide chains does not influence the ability of chondroitin sulfate to adsorb onto coral. In fact, chondroitin sulfate derivatives almost completely sulfated (> 90%) in position 4 of galactosamine and chondroitin almost completely (> 90%) sulfated in position 6 show a full adsorbtion onto coral. Thus, large amounts of chondroitin sulfate are adsorbed onto coral, and sulfate groups are of paramount importance in the adsorption process. On the other hand, the capacity of chondroitin sulfate to adsorb onto coral is quite aspecific. In fact, it does not depend on the presence of sulfate groups esterified in a specific position or sulfated sequences arranged in blocks but rather on the presence of sulfate groups, and this ability increases with increasing charge density, as indicated by the values of the Langmuir constant, the adsorption capacity, that decreases with decreasing chondroitin sulfate charge density reaching very low values for the totally desulfated polymer.
研究了硫酸软骨素在特定直径（100至500微米）、高钙含量（>98%）且表面均匀的天然珊瑚颗粒上的吸附情况。测试了几种不同程度脱硫的硫酸软骨素样品，其硫酸与二糖的比例（电荷密度）为0.98至0.07，以及具有硫酸软骨素主链结构的非硫酸化多糖吸附到珊瑚上的能力。硫酸软骨素在珊瑚上的吸附取决于其电荷密度，因为硫酸基团的去除完全消除了这种能力。还测试了分子量从26,950到1140的各种硫酸软骨素。未发现明显的分子量依赖性影响。此外，分子量约为3530（由约6个二糖单元组成）和1140（由约2个二糖单元组成）的硫酸软骨素级分仍保留其吸附到珊瑚上的全部能力。此外，多糖链内硫酸基团的位置不影响硫酸软骨素吸附到珊瑚上的能力。事实上，在半乳糖胺4位几乎完全硫酸化（>90%）的硫酸软骨素衍生物和在6位几乎完全硫酸化（>90%）的软骨素在珊瑚上表现出完全吸附。因此，大量硫酸软骨素吸附到珊瑚上，硫酸基团在吸附过程中至关重要。另一方面，硫酸软骨素吸附到珊瑚上的能力相当非特异性。实际上，它不取决于特定位置酯化的硫酸基团的存在或成块排列的硫酸化序列，而是取决于硫酸基团的存在，并且这种能力随着电荷密度的增加而增加，如朗缪尔常数、吸附容量的值所示，吸附容量随着硫酸软骨素电荷密度的降低而降低，对于完全脱硫的聚合物达到非常低的值。
