Identification of disulphide-bonded type X procollagen polypeptides in embryonic chick chondrocyte cultures

A high-Mr (Mr 120,000), disulphide-bonded collagenous polypeptide was observed to co-purify with the prox1(X) chain during isolation of cartilage collagens from culture medium of embryonic chick tibiotarsal chondrocytes. This high Mr polypeptide was subsequently shown by two-dimensions l SDS-PAGE and peptide mapping to represent a dimer of the prox1(X) chain of type X collagen linked by disulphide bonding in the non-collagenous domains.