Isolation and characterization of the chains of type V/type XI collagen present in bovine vitreous

Previous studies show that the collagen fibrils of the mammalian vitreous humor are assembled largely from type II collagen with smaller amounts of type IX collagen and either type V or type XI collagen. In this paper, we report the separation of two chains of type V/type XI collagen from type II collagen by heparin-Sepharose chromatography. These chains were characterized by sequencing of selected cyanogen bromide or tryptic peptides with subsequent comparison of these sequences with cDNA-derived amino acid sequences of the alpha 1(V), alpha 1(XI), alpha 2(V), and alpha 2(XI) chains. The results show that vitreous fibrils are assembled from molecules containing the alpha 1(XI) and alpha 2(V) chains. These results, together with recent results from other laboratories, indicate that type V and type XI collagens are not separate collagen types but are part of a larger collagen family in which chains of both type V and type XI collagens participate in the formation of a variety of native molecules.