Figure 4: Site of 3g binding onto thrombin. | Scientific Reports

Figure 4: Site of 3g binding onto thrombin.

From: Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin

Figure 4

(A) Michaelis-Menten kinetics Spectrozyme TH hydrolysis by thrombin in the presence of 3g. The initial rate of hydrolysis at substrate concentrations of 0–250 μM was measured at 25 °C and a pH of 7.4, as described in Experimental Procedures. The concentrations of 3g chosen were 0, 25, 187, and 2500 nM. Solid lines represent nonlinear regression fits to the data using the standard Michaelis-Menten kinetics, equation 2. (B) Dose-response profile of 3g inhibition of thrombin in the presence of an exosite 1 ligand, hirudin peptide ([5F]-Hir-(54–65)-(SO3−)) at 25 °C in buffer of pH 7.4. (C) Dose-response profile of 3g inhibition of thrombin in the presence of an exosite 2 ligand, unfractionated heparin. Solid lines represent sigmoidal dose-response fits using equation 1. (D) Comparison of IC50s of 3g inhibition of recombinant human thrombins. The IC50s were measured using substrate hydrolysis assays, as shown in Fig. 3. The horizontal line is for comparison of change in IC50 of mutants from that of the wild-type recombinant human thrombin.

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