The glycosaminoglycans of pig colonic wall connective tissue

Colon wall from pig, stripped of most of the mucosal layer to leave material largely composed of muscle, basement membrane, and extracellular matrix, was subjected to procedures for isolation of glycosaminoglycans. A total ethanol precipitate from a papain digest was fractionated by selective ethanol precipitation in the presence of Ca²⁺. Glycosaminoglycan fractions, freed proteolytically from a high molecular weight glycoprotein component, were further purified by Sepharose CL-6B gel-filtration or DE-52 anion-exchange chromatography. Glycosaminoglycans were identified by chemical composition, ¹³C-NMR spectroscopy and response to chondroitinase and nitrous acid degradations. The content of glycosaminoglycan in the tissue is low (0.05% dry weight) being comprised of dermatan sulphate (38%), heparin (34%), heparan sulphate (18%) and chondroitin sulphates (10%) as a percentage of total glycosaminoglycan content. Hyaluronic acid and keratan sulphate have not been detected. The composition is generally typical of a high muscle content tissue.