SOME OBSERVATIONS ON THE MOLECULAR FORM OF CHONDROITIN SULPHATE

Abstract

The physical properties of a preparation of chondroitin sulphate extracted from bovine cartilage with calcium chloride have been measured at various stages of purification. After removal of free protein, the extract has a number-average molecular weight, from sedimentation and viscosity data, of about 1.0 × 106. After tryptic digestion, the molecular weight of the extract is 39,000 on a number average basis from sedimentation and viscosity data, and about 145,000 on a weight average basis from light scattering data. At both stages of purification, the extract is widely polydisperse and exhibits streaming birefringence in aqueous but not in salt solution. Before digestion, the particles evidently represent aggregates of polysaccharide molecules linked in an end-to-end arrangement by peptides; tryptic digestion partially destroys these peptide linkages. It does not appear, from a partial analysis of the amino acids present, that the origin of the protein or peptide material is collagen.