FIGURE 1.
Binding of exosite-directed ligands to fluorescently labeled Quick I-thrombin. After determining the initial fluorescence intensity (Io) of 50 nm 5-IAF-Quick I-thrombin (λex 492, λem 532 nm), fluorescence (I) was monitored as the sample was titrated with aliquots of either 200 μm γ′-peptide (▴), 66.7 μm heparin (♦), or 1 mm HD22 (inset). Values of I/Io were then calculated and plotted as a function of the titrant concentration, and the Kd values were determined by nonlinear regression analysis (lines). Data represent the means ± S.E. of three experiments.