Quenching of tryptophan fluorescence in human antithrombin III by iodide ion.
Iodide is an efficient quencher of antithrombin III intrinsic tryptophan fluorescence. The quenching pattern indicates that about 60% of the tryptophyl fluorescence originates from exposed residues in the multitryptophan-containing protein. In denaturing media all of the tryptophyls are solvent-exposed. The binding of heparin to antithrombin III influences the number of solvent-exposed tryptophan residues. By studying the dependence of the quenching on pH, information regarding the presence of charged residues adjacent to tryptophyls was obtained.
D000991:Antithrombins; D005453:Fluorescence; D006493:Heparin; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007454:Iodides; D014364:Tryptophan
D000991:Antithrombins; D007454:Iodides; D014364:Tryptophan; D006493:Heparin