Rabbit knee-joint meniscal proteoglycans.

A major proteoglycan (PG) in rabbit meniscal fibrocartilage was extracted with 4 M guanidine-HCl. It represented 63% of the total uronic acid originally present in the tissue. The non-extractable PG could be released by treating the guanidine HCl-extracted tissue with trypsin followed by alkaline hydrolysis. The glycosaminoglycan (GAG) chains from the non-extractable PGs are shown to be of a different type than the extractable forms since the relative amounts of chondroitin sulphate isomers differ from each other.