Presence of the HNK-1 epitope (3-sulfoglucuronic acid) on oligosaccharides from squid skin chondroitin proteoglycans and degradation of proteoglycans by proteolytic enzymes.

Using competitive ELISA it was found that chondroitin proteoglycans from the skin of squid, which is a primitive organism, are reactive with the HNK-1 monoclonal antibody and that all HNK-1 epitopes of the proteoglycans were present only on their oligosaccharides. Although of the presence of appreciable amounts of glycine, serine and glutamic acid and the absence of hydroxyproline, the proteoglycans were degraded by collagenase and other proteolytic enzymes.