Characterization of Decorin of the Human Yellow Ligament

Decorin, a component of the low-molecular-weight proteoglycans (PG) of yellow ligaments was purified, and the structures of the core protein and the glycosaminoglycan (GAG) chains were analyzed. The crude PG fraction extracted under dissociative conditions was subjected to DEAE-Sephacel ion-exchange chromatography, gel-filtration on Sepharose CL-4B, and Octyl-Sepharose CL-4B chromatography, and decorin was obtained. The amino-terminal amino acid sequence of decorin was found to be identical to those of human bone PG-II and human fetal membrane PG-II. The analyses of the GAG chains using two-dimensional electrophoresis on cellulose acetate membranes, affinity high-performance liquid chromatography (HPLC) with a hydroxyapatite column and gel-filtration HPLC after chondroitinase digestion, showed the presence of dermatan sulfate (DS) chains and chondroitin sulfate (CS). Further, it was suggested that CS located in the reducing termini and DS in the non-reducing termini in the hybrid chain.