Isolation and characterization of proteoglycans from bovine aorta.

Proteoglyeans from bovine aorta were extracted by 0.15 M NaCl and by digestion with collagenase and with elastase. The nonspecific protease activity of elastase was inhibited by soybean trypsin inhibitor. Glycosaminoglycans (GAG) of the proteoglycans were isolated, characterized, and quantitated. About 50% of the tissue chondroitin 4and B-sulfates, 75% of hyaluronic acid, and almost all chondroitin were extracted from the tissue by 0.15 M NaCl. Collagenase solubilized most of the chondroitin sulfates and part of the dermatan sulfate of the aorta. Elastase solubilized most of the heparan sulfate of the tissue and a large amount of dermatan sulfate. Sequential extraction of the tissue by NaCl, collagenase, and elastase yielded proteoglycans with varied GAG and protein compositions. Proteoglycans extracted by 0.15 M NaCl contained 13.2% protein and 18.8% hexuronic acid with 85% chondroitin 6-sulfate and 15% chondroitin I-sulfate of the total GAG. Collagenase-solubilized proteoglycans from NaCl-extracted residue had 10.3% protein and 20.6% hexuronic acid with 77% chondroitin 6sulfate, 14% chondroitin 4-sulfate, and 9% dermatan sulfate of the total GAG. The major proteoglycan obtained from collagenase-extracted residue by hydrolysis with elastase contained exclusively heparan sulfate with a protein content of 15.2%. Although the precise association of these proteoglycans with other constituents of the connective tissue of the arterial wall is not clearly established, it is suggested that chondroitin sulfate-dermatan sulfate proteoglycan is bound to collagen, and heparan sulfate proteoglycan to elastin.