Figure 11.

Theoretically and experimentally probing the effects of a competitive inhibitor on activity. (A) Data points show experimentally measured activity in arbitrary units from Li et al. for the enzyme α-amylase using substrate analogue [S] (α-maltotriosyl fluoride) and competitive inhibitor [C] (isoacarbose).⁵¹ Best fit theoretical curves described by the inverse of eq 65 are overlaid on the data. The best fit parameters are e^{−β(ε_A−ε_I)} = 36, $K_{\mathrm{M}}^{\mathrm{A}}=0.9\text{mM},K_{\mathrm{M}}^{\mathrm{I}}=2.6\text{mM},C_{\mathrm{D}}^{\mathrm{A}}=12\text{nM},C_{\mathrm{D}}^{\mathrm{I}}=260\text{nM}$, and $\frac{k_{\text{cat}}^{\mathrm{A}}}{k_{\text{cat}}^{\mathrm{I}}}=1.4$. Note that the x-axis varies [C] rather than [S] as in most other plots. (B) A data collapse of the three curves using the Bohr parameter ΔF from eq 68 which encompasses the effects of both the substrate and inhibitor upon the system.