Water soluble proteoglycans from bovine duodenal mucosa

Glycosaminoglycan-protein complexes were extracted from bovine duodenal mucosa with distilled water, resulting in solubilization of a fraction of the total proteoglycan of the tissue. The extracted material was purified by anion exchange chromatography on DEAE-Sephadex A-25, and then characterized by chemical analysis and by fractionation on Dowex 1. By using these procedures, two major fractions were identified, which were eluted from Dowex with 1.0-1.25 M NaC1 and with 1.5-1.75 M NaC1 respectively. Analyses showed that both fractions were mainly composed of glucosamine-containing, hyaluronidase-resistant polysaccharides, which were identified by their N-sulphate: D-glucosamine and total sulphate: D-glucosamine ratios as heparan-sulphate in the less acidic fraction, and as heparin in the more acidic fraction. Dermatan sulphate molecules were also present in both preparations, with an approximate ratio 1:3 to the glucosamine-containing polysaccharides. Solubility behaviour of the complexes formed by the isolated polyanionic molecules with cetylpyridinium chloride was strongly modified by papain digestion of the duodenal material. This reduction of molecular size of papain treatment suggests that the molecules extracted with water from duodenal mucosa are complex proteoglycans, perhaps in the native state.