The chemistry of connective tissues. 1. The state of combination of chondroitin sulphate in cartilage

Abstract

The intercellular substance of bovine nasal cartilage is composed almost exclusively of 2 major components[long dash]collagen and chondroitin sulfate. A soluble mucoid may be extracted from dried cartilage powder after a short heat treatment with water at 60-70[degree] The temp, required to liberate mucoid is reduced in the presence of inorganic salts, alkalis and formamide, and the conditions necessary to secure extraction in good yield are generally those which give rise to thermal contraction of collagen. The mucoid contains chondroitin sulfate and a protein derived from the degradation of collagen. Prepared under the lowest effective temp, conditions, the mucoid behaves in the electrophoresis apparatus of Tiselius as an equilibrium mixture of chondroitin sulfate, protein and a complex formed between the two. The association of chondroitin sulfate with protein in the mucoid occurs over the range of pH 5-9 within which both the protein and the acid polysaccharide are negatively charged. The complex formation is of a different type from the salt formation known to occur below pH. 4.85. On further heating, the mucoid loses its capacity to form complexes at pH 5-9 and suffers a rapid reduction in viscosity. The part played by such complex formation in the intact tissue is discussed and it is suggested that chondroitin sulfate has an important role in the organization of collagen in developing connective tissue.