Quantitative and qualitative analyses of proteoglycans in cartilage extracts by precipitation with 1,9-dimethylmethylene blue.

The dye 1,9-dimethylmethylene blue may be used for the specific and quantitative precipitation of sulphated glycosaminoglycans as well as proteoglycans from the extracts of articular cartilage. The consumption of the dye DMMB enables to determine the amount of the proteoglycans present in the extract, by measuring the decrease of the absorption at 595 nm. The precipitated complex of DMMB and proteoglycans is used for qualitative investigations into the electrophoretic mobility of the different proteoglycans in agarose slab gel and their immunological characterization after blotting. Because of its higher sensitivity and greater simplicity the method described in this report is a promising alternative to the procedure based on alcian blue.