The nature of the protein in the hyaluronic complex of bovine synovial fluid

Abstract

The protein was isolated from the hyaluronic acid-protein complex of Ogston and Stanler. Evidence was obtained showing by physical and immunological tests that the protein is entirely derived from the serum. The protein composition of the hyaluronic acid complex varies with pH and ionic strength. At pH 5.8 [alpha]-globulins predominate, at pH 7-8 [alpha]- and [beta]-globulins participate, and at pH 10 the protein content is reduced considerably, the protein combining being mostly [gamma] -globulin. At neutrality increasing ionic strength led to a marked increase in the amount of protein in the complex. It is suggested that the protein associates with the hyaluronic acid through a process akin to salting-out adsorption. Sedimentation measurements in the ultracentrifuge were made on the proteins isolated under various conditions from the hyaluronic acid complex of ox synovial fluid. The results are consistent with the protein resembling a serum globulin; however, the change of sedimentation rate with concentration of buffer salt differs from that shown by serum a-globulin.