Extracellular mammalian polysaccharides: glycosaminoglycans and proteoglycans

Abstract

This review of the mammalian extracellular matrix polysaccharides covered the glycosaminoglycans (GAGs) and their association into proteoglycans. As they necessarily pertain to the chromatographic and electrophoretic separations of these molecules, the structural features of the five principal GAGs were briefly reviewed. Much of the current structural work as well as the separation technology has been concerned with the sulfation state and copolymeric sequences of the individual classes of GAGs. The separation methods discussed included electrophoresis by agarose, acrylamide and cellulose acetate, high-performance liquid chromatography (HPLC), ion-exchange, gel permeation and biospecific affinity methods. Since detection systems are an integral part of chemical separation technology, current thoughts about the best methods to assay GAGs or detect column fractions were discussed. These included polysaccharide-specific detection systems such as Alcian blue dye, 1,9-dimethylmethylene blue, bovine serum albumin-Coomassie blue, as well as non-specific carbohydrate detection systems such as the carbazole or indole hydrochloride methods. Instrumentation used in the detection of chromatography fractions for these molecules was discussed, since the usual ultraviolet detector, standard with HPLC equipment, is often unsatisfactory. The most sensitive specific detection method for GAGs is the use of monoclonal antibodies, which are only now becoming commercially available. The use of these antibodies, combined with HPLC separation, appears to be the best available biochemical technology for studying the extracellular matrix polysaccharides. Finally, the association between proteoglycans, GAGs and mammalian disease processes was reviewed, emphasizing mucopolysaccharidoses and arthritis. The early detection of both of these diseases is desired for effective counselling and treatment. Many of the methods discussed here have been applied, but others are yet to be tried in efforts to further that goal.