title: Binding of tissue plasminogen activator to human umbilical vein endothelial cells.
abstract: Binding of purified recombinant human tissue plasminogen activator to cultures of human umbilical vein endothelial cells (HUVEC) was studied in vitro. 125I-tPA was shown to bind to HUVEC in a specific, saturable, and dissociable manner. Scatchard analysis revealed a low affinity binding site with Keq = 4.2 X 10(6) M-1 and 1.2 X 10(7) sites per cell. Binding of tPA was inhibited by L-lysine, e-aminocaproic acid, and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone but not by carbohydrates including mannose, galactose, N-acetyl glucosamine and N-acetyl galactosamine. Neat human plasma abrogates but does not totally inhibit binding of tPA to HUVEC. These results may indicate a role for endothelial cells in the removal of tPA from the circulation in vivo.
mesh_terms: D000614:Aminocaproates / Q000494:pharmacology; D001665:Binding Sites; D001667:Binding, Competitive; D002241:Carbohydrates / Q000494:pharmacology; D002478:Cells, Cultured; D004727:Endothelium / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008239:Lysine / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014471:Umbilical Veins / Q000378:metabolism*
chemical_list: D000614:Aminocaproates; D002241:Carbohydrates; D010959:Tissue Plasminogen Activator; D008239:Lysine