title: On the composition and function of the carbohydrate moiety of tissue-type plasminogen activator from human melanoma cells.
abstract: Two variants (I and II) of tissue-type plasminogen activator (t-PA) from human melanoma cells were separated by Lysine Sepharose chromatography. The carbohydrate compositions of the forms were determined by gas-liquid chromatography. Variant I contained 12.8 g and variant II 7.1 g of carbohydrate per 100 g protein. Both variants contained N-acetylgalactosamine, suggesting O-glycosylation in addition to N-glycosylation. The possible role of N-linked oligosaccharides for the biological activity of t-PA was studied using t-PA secreted by melanoma cells in the presence of tunicamycin, an inhibitor of N-glycosylation. The latter t-PA showed the same plasminogen activating and fibrin binding properties as normally glycosylated t-PA, indicating that N-linked carbohydrate is not involved in the fibrinolytic activity of t-PA.
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D002478:Cells, Cultured; D002847:Chromatography, Agarose; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000302:isolation & purification / Q000378:metabolism*; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D002241:Carbohydrates; D014415:Tunicamycin; D005337:Fibrin; D010959:Tissue Plasminogen Activator