Characterization of a proteoglycan of high electrophoretic mobility.

Proteoglycans from articular cartilage of young baboons (Papio papio) were fractionated on an associative density gradient. Material from the top of the gradient was shown to contain a proteoglycan of high electrophoretic mobility on large porosity gels. Associated and/or contaminating proteins were removed by ion-exchange chromatography on DEAE-cellulose and subsequent gel filtration on Sepharose 4B in the presence of 0.1% SDS. The electrophoretically homogeneous proteoglycan (Kd 0.43 on Sepharose 4B SDS) contained 39.7% protein, was rich in aspartate, glutamate, leucine and glycine and had a GalN : GluN molar ratio of 3.87.