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Counterion binding and hydration of hyaluronate and chondroitin in solution: An 17O, 23Na, and 25Mg nuclear-magnetic-relaxation study

✍ Scribed by Lennart Piculell; Björn Lindman; Roland Einarsson


Publisher
Wiley (John Wiley & Sons)
Year
1984
Tongue
English
Weight
890 KB
Volume
23
Category
Article
ISSN
0006-3525

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✦ Synopsis


Nuclear magnetic relaxation rates of H,"O, Z.'Na+, and ""Mg'have been measured in aqueous hyaluronate solutions. The dependence on solution pH of the relaxation rates has been investigated, as well as the competition behavior of N a + with Ca2 and M g L -. € I L ' 7 0 and L:'Nai relaxation rates in chondroitin and hyaluronate solutions have been compared in the interval, 2 5 pH 5 12.5. The ion binding of hyaluronate can be fully accounted for by Coulomb interactions, with no need to involve chemical specificity. The hydration is only slightly pH dependent, and is comparable in magnitude to hydration of synthetic polyelectrolytes and monosaccharides. Ion-binding and hydration properties of hyaluronate and chondroitin are quite similar, except at elevated pH. At alkaline pH, an increase in charge density with pH is seen in hyaluronate and, to a much lesser degree, in chondroitin, possibly due to the titration of hydroxy groups.

H,':O data indicate an alkali-induced transition in both glycosaminoglycans.