title: Degradation of proteoglycan in articular cartilage.
abstract: Adult rabbit articular cartilage was labelled in vivo over 48 h with [35S]sulphate and was then incubated in organ culture at pH 7.2. Approx. 65% of the tissue content of [35S]proteoglycan was released into the culture medium during the first 48 h of incubation. The average molecular size of the released proteoglycans, as assessed by fractionation on Sepharose 2B/CL and 4B/Cl, was only slightly smaller than that of the proteoglycans extracted from non-cultured cartilage with 4 M guanidine HCl. The percentage of released proteoglycans and extracted proteoglycans which formed aggregates with hyaluronic acid was approx. 25% and 75%, respectively. The results indicate that proteoglycan degradation in adult articular cartilage is initiated by a limited proteolysis of subunit core protein, with the production of non-aggregating species which diffuse readily from the tissue.
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008970:Molecular Weight; D009924:Organ Culture Techniques; D010447:Peptide Hydrolases / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism*; D011817:Rabbits
chemical_list: D011509:Proteoglycans; D006820:Hyaluronic Acid; D010447:Peptide Hydrolases