title: Identification of collagens isolated from bovine Descemet's membrane.
abstract: In this study collagens were isolated and identified from a morphologically pure preparation of bovine Descemet's membrane (DM) which was obtained by gentle scraping of the cornea, sieving and subsequent treatment with detergents. An alternative procedure of DM isolation with forceps resulted in stromal contamination of the preparation as verified by light and transmission electron microscopy, and gel electrophoresis. The amino acid profile of collagens isolated by pepsinization and salt precipitation from the pure sample was similar to the analysis of the intact bovine DM. Polyacrylamide gel electrophoresis of this collagen under non-reducing conditions resulted in five major bands: 300 000 daltons (300 K), 200 000 daltons (200 K), 100 000 daltons (100 K) and lower molecular weight fractions (50 K1 and 50 K2). Individual collagen chains were isolated from preparative polyacrylamide gels and characterized by 125I two dimensional peptide mapping patterns. This data suggests that (1) the majority of collagen fragments seen in bovine DM pepsin supernatant are derived from a single genetically distinct collagen molecule, and (2) that type I and V collagens are not major components of bovine DM.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001485:Basement Membrane / Q000032:analysis; D002417:Cattle; D003094:Collagen / Q000032:analysis / Q000302:isolation & purification*; D003886:Descemet Membrane / Q000032:analysis* / Q000648:ultrastructure; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D012756:Sheep
chemical_list: D000596:Amino Acids; D003094:Collagen