Isolation and preliminary characterization of proteoglycans dissociatively extracted from human aorta

Aortic proteoglycans (PG) were isolated from human aorta intima-media preparations with 4 M guanidine hydrochloride in the presence of protease inhibitors. The extracted PG mixture comprised 67% of the total aortic PG and was composed of 65% chondroitin sulfate, 22% dermatan sulfate, 8% heparan sulfate, and 4% hyaluronate. Attempts at isolation and purification of PG monomers using isopycnic CsCl gradient centrifugation under associative and dissociative conditions resulted in appreciable loss of PG through associations with co-extracted aortic proteins. The addition of a gel chromatographic step on Sepharose CL-4B under dissociative conditions resulted in separation of PG from the majority of co-extracted proteins. In addition, the procedure resulted in a separation of the PG into a population (PG-I) eluting near the column V0 and one (PG-II) included with a Kav of 0.38. Hyaluronic acid co-eluted with PG-I. The major glycosaminoglycan in PG-I was chondroitin sulfate, (85 to 95%). No dermatan sulfate was detected in PG-I, but this glycosaminoglycan was the predominant glycosaminoglycan in PG-II (50 to 70%). Heparan sulfate was present in small amounts in both PG-I and PG-II. Data presented support the proposal of at least three species of PG monomers in the aortic wall. Chromatographic studies under dissociative and associative conditions indicated that PG comprising PG-I but not PG-II were capable of associations with hyaluronic acid.