The binding of 1-anilino-8-naphthalenesulfonate, heparin, salicylate and caprylate by human antithrombin III.
The binding of 1-anilino-8-naphthalenesulfonate to human antithrombin III was studied by fluorescence enhancement of the fluorophor and fluorescence quenching of the protein emission. Two molecules of 1-anilino-8-naphthalenesulfonate were found to bind per antithrombin molecule with an average dissociation constant of 4.4-10(-5) M. The binding of heparin to antithrombin was studied by ultraviolet difference spectroscopy. The stoichiometry of the heparin binding indicated 1.8 binding sites with an average dissociation constant of 4.3 - 10(-6) M. Further the fluorometric competition experiments with 1-anilino-8-naphthalenesulfonate, heparin, salicylate and caprylate indicated two different classes of anion binding sites on the antithrombin molecule.
D000817:Anilino Naphthalenesulfonates; D000991:Antithrombins; D001665:Binding Sites; D002210:Caprylates; D006493:Heparin; D007700:Kinetics; D011485:Protein Binding; D012459:Salicylates; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D000817:Anilino Naphthalenesulfonates; D000991:Antithrombins; D002210:Caprylates; D012459:Salicylates; D006493:Heparin