Studies of biologic properties of proteoglycans from bovine aorta

Chondroitin sulfate-dermatan sulfate proteoglycans (PG) were isolated from bovine aorta-intima by extraction with 4.0 M guanidinium chloride in the presence of protease inhibitors and purified through cetylpyridinium complexes. The PG were fractionated by CsCl isopyknic centrifugation into three fractions with different chemical composition. The anticoagulant activity of the PG fractions was studied by Stypven time, partial thromboplastin clotting time (PTT), and thrombin time assays. The three PG fractions delayed coagulation in the three assays. The PG fractions did not affect the ADP and collagen-induced platelet aggregation but inhibited the aggregation induced by 0.2 units per ml. of thrombin. The PG fractions released lipoprotein lipase in rabbits when injected, and the enzyme activity released by the major PG fraction was approximately 60 per cent of that of heparin. This PG fraction interacted with serum low density lipoproteins but not with high density lipoproteins. Certain biologic properties are probably due to the presence of dermatan sulfate in the PG fractions. These studies suggest important functional roles for PG in the arterial wall.