Molecular size distribution of proteoglycans in human inflamed gingival tissue

Proteoglycans were extracted from human gingiva with 2 M CaCl 2. The extracts were examined by gel filtration on Sephacryl S-400 in 2 M CaCl 2 under dissociative conditions. The 280 nm absorbance profiles of clinically uninflamed, inflamed and severely-inflamed tissues showed that material was present with molecular weights of between 2 × 10 6 or greater, and 16,000. Proteoglycans were examined by cellulose-acetate electrophoresis with subsequent identification of the constituent glycosaminoglycans after protease digestion, and finally by chondroitinase AC digestion of the liberated glycosaminoglycans. The relative proportion of each glycosaminoglycan was calculated by scanning each cellulose-acetate sheet on an integrating densitometer. Heparan sulphate was found only in fraction I (mol. wt 2 × 10 6 or greater), together with hyaluronic acid and chondroitin-4-sulphate, these being present in all of the glycosaminoglycan-containing fractions (I–1V). Dermatan sulphate was absent from fraction I, but present in II–IV, apparently existing on the same protein core as chondroitin-4-sulphate. The relative proportions of these two glycosaminoglycans was related to molecular size, and with the degree of inflammation for a given molecular species.