The non-ultrafilterable acidic glycosaminoglycans from pooled urine of normal men, aged about 20, were isolated and characterized. The isolation procedure included digestion with sialidase and pronase, and fractionation by stepwise elution from an ECTEOLA-cellulose column. The glycosaminoglycans in each fraction were separated from each other by preparative electrophoresis in sodium barbital buffer and in barium acetate. 2. Approximate relative amounts of the different glycosaminoglycans were: chondroitin sulphate 60%, chondroitin 2%, hyaluronic acid 4%, dermatan sulphate 1%, heparan sulphate 15% and keratan sulphate 18%. Chondroitin sulphate-dermatan sulphate hybrids seemed to occur in trace amounts. 3. Chondroitin sulphate, heparan sulphate and keratan sulphate were heterogeneous with respect to degree of sulphation. Two distinct groups of chondroitin sulphate fractions were found, with sulphate/hexosamine molar ratios of about 0.5 and 1 respectively. The sulphate/hexosamine molar ratios in the heparan sulphate fractions varied from 0.5 to 0.9; the N-sulphate/hexosamine ratio was about 0.5 in all fractions. The sulphate/hexosamine molar ratios in the keratan sulphate fractions varied from 0.2 to 0.7.
