Fig. 3. Incorporation of [35S]sulfate into keratocyte glycosaminoglycans as a function of cell phenotype.
Incorporation of [35S]sulfate into keratan sulfate and chondroitin/dermatan sulfate during an 18-h labeling period was determined by digestion of a purified proteoglycan fraction with keratanase II + endo-β-galactosidase (A) or chondroitinase ABC (B and C) as described under “Experimental Procedures.” Values are corrected for cell protein, and error bars represent the mean ± S.D. of assays on triplicate cultures. Values are normalized so that keratocyte = 100 in each assay. In C, cultures were labeled in the presence of 0.5 mM 4-nitrophenyl-β-D-xyloside.