Chemical and immunochemical characteristics of proteoglycans in bovine gingiva and dental pulp

Proteoglycans were extracted with 4 M guanidinium chloride at 6 °C and purified by ion-exchange chromatography and precipitation with cetyl-pyridinium chloride. Chromatography on Sepharose CL-4B under dissociating conditions separated larger (PG1) and smaller (PG2) proteoglycans. Gingival PG2, by virtue of its amino-acid composition and the exclusive presence of l-iduronate-rich dermatan sulphate, was a proteodermatan sulphate (PDS) with a similar molecular weight to periodontalligament PDS. Reaction with four monoclonal antibodies to bovine skin PDS confirmed the relationship between these small proteoglycans and that of skin. Their glycoprotein cores, liberated by digestion with chondroitinase ABC, were similar in size (mol. wt = 55,000 by SDS-gel electrophoresis). Pulp PG2 had a small amount of PDS but the main component contained d-glucuronate-rich sulphated galactosaminoglycans. Similar galactosaminoglycans, which included chondroitin sulphate, characterized the larger proteoglycans of gingiva and pulp; significant amounts of l-iduronic acid-rich dermatan sulphate or heparan sulphate were not present.