Studies on hyaluronic acid. I. The preparation and properties of rooster comb hyaluronic acid.

1. 1. Hyaluronic acid has been prepared quantitatively from the rooster comb under mild conditions, with a yield of 6% of the acetone-dried combs. 93% of this hyaluronic acid was extracted with distilled water, while stronger treatments, 1 M NaCl extraction and digestion with pronase, were required to remove the remainder of the hyaluronic acid from the comb tissues. 2. 2. The crude extracts were purified by a modified Sevag 's procedure, epichlorohydrin triethanolamine- (ECTEOLA-) chromatography and by fractionation with cetylpyridinium chloride. Hyaluronic acid purified by these procedures was recovered with a yield of greater than 90% with respect to hexuronic acid. 3. 3. Analysis of the purified products by physical and chemical methods showed that the hyaluronic acids in each fraction were identical with respect to their hexuronic acid and glucosamine content, their infrared absorption, optical rotation and electrophoretic mobility. Viscosity measurements and molecular weight determinations using a sedimentation equilibrium method showed the purified hyaluronic acids from each fraction to be of different molecular sizes. 4. 4. The significance of these results is discussed in relation to the known structure and chemical composition of hyaluronic acid and the rooster comb.