Purification and characterization of hyaluronic acid from the horny layer of guinea pigs.

Hyaluronic acid was purified from the horny layer of guinea pigs and its biochemical and physical properties were studied. The horny layer, obtained by applying n-hexadecane to guinea pig skin, was digested with pronase, and glycosaminoglycans in the digest were separated from UV-absorbing material by Sephadex G-75 chromatography (sample A, 17.5 mg). On DEAE-Sephadex chromatography, the fraction obtained with 0.5 M NaCl was found to contain 94% of the total uronic acid. This fraction, consisting mainly of hyaluronic acid, was dialyzed and lyophilized (sample B, 12.5 mg). Sample B, consisting of 26.1% uronic acid and 27.0% glucosamine on a dry weight basis, could be digested completely with Streptomyces hyaluronidase. Sample B had a low reduced viscosity which showed almost no concentration dependence. The intrinsic viscosity of sample B was 0.83 dl/g and its molecular weight, calculated from its viscosity, was 34,000. Sample B was eluted from Sepharose CL-6B as a broad peak between the void volume and the total column volume. The enzyme levels of hyaluronidase, beta-glucuronidase, and beta-N-acetylglucosaminidase in the n-hexadecane treated guinea pig skin increased to 1.7 to 2.5 fold those of controls after 6 days of the experiment. These results suggested that hyaluronic acid in the horny layer of n-hexadecane treated guinea pig skin might be degraded by hyaluronic acid degrading enzymes in the hyperkeratinized tissue.