Self-association of hyaluronate segments in aqueous NaCl solution

The potential for self-association by hyaluronate (HA) chains in 0.15 M NaCl was investigated, using low molecular weight HA segments as a model system. HA segments were derived from the polymer by controlled enzymatic digestion, and purified by gel filtration chromatography. Seven samples of narrow molecular weight distribution were analyzed by sensitivity-enhanced polyacrylamide gel electrophoresis, and found to have the following weight-average numbers of repeating disaccharide units: A, 90; B, 51; C, 38; D, 31; E, 23; F, 18; G, 13. The segment preparations were studied in 0.15 M NaCl by capillary viscometry, low angle laser light scattering, and circular dichroism spectroscopy. The data indicate concentration-dependent intermolecular association of short segments, and a capability for intramolecular association (hairpin formation) by larger HA segments.