Aggregation of cartilage proteoglycans. II Evidence for the presence of a hyaluronate-binding region on proteoglycans from osteoarthritic cartilage.

Proteoglycan aggregates isolated from normal bovine knee cartilage were larger than those from osteoarthritic cartilage of the same joints and appeared relatively more resistant to digestion with leech hyaluronidase. Incubation of proteoglycan subunits from the arthritic cartilage with hyaluronic acid resulted in marked aggregation, comparable in magnitude to that shown by subunits from normal cartilage. The results indicate that the hyaluronate-binding region of these proteoglycans was functionally intact and suggest that diminished aggregation of proteoglycans in osteoarthritic cartilage may be due to an abnormality in some other constituent of the aggregates.