The corneal mucopolysaccharide

Publisher Website
Google Scholar
Abstract
The ester-S present in the cornea corresponds to a mucopolysaccharide content of 4.2%. There is an excess of hexosamine over that required as a constituent of the mucopoly-saccharide. By extraction of the water-swollen sections of cornea with 10% CaCl2 at pH 8, 85% of the mucopolysaccharide can be dissolved. Extraction with CaCl2 is more efficient than extraction with NaCl and that is more efficient than extraction with water. The mucopolysaccharide is extracted as a component of both water-soluble and water-insoluble mucoids. The protein content of the water-soluble-mucoids can be reduced by extraction with phenol to leave a phenol-insoluble mucoid. This contains a substance with the characteristics of a mucopolysaccharide-protein complex. The water-soluble mucoids contain a complex which is formed by interaction between the phenol-insoluble mucoids and a water-soluble protein of the cornea. The acid mucopolysaccharide can be prepared free from protein by incubation with trypsin. Galactose, glucosamine and galactosamine were identified as constituents of the mucopolysaccharide, by chromatography and ionophoresis on filter paper. The corneal mucopolysaccharide is not a substrate for hyaluronidase. Gel-forming proteins were isolated from the insoluble mucoid and found to contain the same amino-acids as gelatin, but to differ from it in their electrophoretic behavior. It is suggested that in situ the acid mucopolysaccharide is combined with proteins of the collagen group.