Isolation and characterization of a glycoprotein secreted by aortic endothelial cells in culture. Apparent identity with platelet thrombospondin.
A high molecular weight glycoprotein, reported to be secreted by endothelial cells (Sage, H., Crouch, E., and Bornstein, P. (1979) Biochemistry 18, 5433-5442), has been purified to apparent homogeneity from culture medium of adult bovine aortic endothelial cells. Purification was achieved by ammonium sulfate fractionation and successive chromatography on gelatin-Sepharose, Sephacryl S-300, and hydroxylapatite. The glycoprotein was found to be a disulfide-linked oligomer with a subunit molecular weight of 190,000, as judged by its mobility on sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gels. The endothelial cell-derived protein is distinct from high molecular weight serum glycoproteins such as fibronectin and alpha 2-macroglobulin. However, immunological and structural studies indicate that the Mr = 190,000 glycoprotein is either identical with or closely related to thrombospondin, a glycoprotein contained in platelet granules and released in response to thrombin-induced aggregation.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism*; D001792:Blood Platelets / Q000032:analysis*; D002417:Cattle; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D004727:Endothelium / Q000378:metabolism; D006023:Glycoproteins / Q000302:isolation & purification* / Q000378:metabolism*; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D019699:Thrombospondins
D000596:Amino Acids; D006023:Glycoproteins; D010446:Peptide Fragments; D019699:Thrombospondins