Isolation and characterization of proteodermatansulfate from rat skin.

A proteodermatansulfate was extracted from rat skin with 4 M guanidine hydrochloride containing protease inhibitors at 4 degrees C. It was separated from collagen on DEAE-cellulose in 7 M urea and was purified by cesium chloride density gradient centrifugation under associative conditions, DEAE-Sephadex column chromatography and then Sephadex G-200 gel filtration. On SDS-disc electrophoresis, the proteoglycan gave a single band staining for protein and a band of the same mobility staining with periodate-Schiff reagent. The proteoglycan contained 46% protein, and this was bound to dermatansulfate via an O-glycosidic linkage. The proteoglycan also contained 20% uronic acid and 16% hexosamine, but no detectable hydroxyproline. The ratio of galactosamine to glucosamine was 68. The dermatansulfate, the only glycosaminoglycan, had a hybrid structure containing iduronic acid and glucuronic acid as uronic acids. The content of glucuronic acid in uronic acid was much higher than that of pig skin dermatansulfate. The dermatansulfate had a slightly higher mobility on cellulose acetate electrophoresis than those from other sources. Gel chromatography on Sepharose CL-6B showed that the molecular weight of the dermatansulfate was 23,000, while that of the proteoglycan was 36,000. The elution profile of a mixture of the proteoglycan and hyaluronic acid on Sepharose 6B column chromatography was similar to that of the proteoglycan alone.