Galactosaminoglycan composition in chicken eggshell

Galactosaminoglycans, isolated from decalcified chicken eggshell by papain digestion and ion-exchange chromatography, were fractionated by selective precipitation at varying concentrations of ethanol and characterized by chemical and enzymatic methods. The eggshell contained 0.15 microg galactosaminoglycan uronic acid/mg dry weight. Most (to approximately 87% of total) galactosaminoglycans were found to be chondroitin sulfate-dermatan sulfate copolymers with iduronic acid contents being approximately 20 to 30% of uronic acid. The remaining (to approximately 12% of total) galactosaminoglycans were chondroitin sulfate-dermatan sulfate copolymers with higher iduronic acid contents averaging 59% of uronic acid. Results of chondroitinase-ABC digestion demonstrated 4-sulfated disaccharides to be the major repeating units in the chicken eggshell galactosaminoglycans.