Figure 4

Nonlinear least-squares fit of inhibition data for human mast-cell tryptase ([E]₀ = 0.05 nM). The inhibitor was benzamidine doped with the tight binding inhibitor CRA-001390. Curve A is the best-least squares fit to Equation (2) for a pure tight binding or classical inhibitor. Note the pronounced lack of fit (dashed curve misses most of the data points). Curve B is the best least squares fit to Equation (4) for a mixture of a classical inhibitor contaminated with a tight binding inhibitor. The best-fit values were molar fraction a = (0.09 ± 0.02)%, apparent inhibition constant K_T = (107 ± 35) pM. The actual values for inhibitor CRA-001390 were a = 0.02%, K_T = 65 pM (ref. [1]).