Biochemical characteristics of dissociatively isolated aortic proteoglycans and their binding capacity to hyaluronic acid.

Proteoglycans were extracted from pigeon aortas with 4.0 M guanidine hydrochloride containing protease inhibitors to characterize the proteoglycan (PG) types, to examine and define their association with hyaluronic acid, and to compare pigeon aortic PG with human aortic PG isolated and characterized under similar conditions. Following chromatography of guanidine hydrochloride extracts on Sepharose CL-4B under dissociative conditions, two populations of PG were isolated. PG I, eluting at the column void volume, contained predominantly (83.2%) chondroitin sulfate whereas PG II, eluting at a Kav of 0.40, contained predominantly dermatan sulfate (54.7%). Following centrifugation, 76 and 63% of PG I and PG II, respectively, were located in the bottom two-fifths (p greater than 1.43 g/ml) of a CsCl gradient. Only PG I, predominantly chondroitin sulfate, was effective in associating with hyaluronic acid to form high molecular weight aggregates. The specific association was illustrated by removing endogenous arterial hyaluronic acid remaining in the preparation and demonstrating increasing formation of aggregate with increasing addition of human umbilical cord high molecular weight hyaluronic acid. The results of the study illustrate that artery PG of the pigeon are similar in distribution to those described for the human aorta and contain at least three types of PG, a chondroitin sulfate PG, a dermatan sulfate PG, and a polydisperse heparan sulfate PG. The chondroitin sulfate PG but not the dermatan sulfate PG are capable of forming high molecular weight aggregates with hyaluronic acid.