Figure 1. The temperature-dependence of enzyme activity.

(A) Experimental data for alkaline phosphatase. The enzyme was assayed as described by Peterson et al. [2], and the data were smoothed as described here in the Experimental section; the data are plotted as rate (μM·s⁻¹) against temperature (K) against time during assay (s). (B) The result of fitting the experimental data for alkaline phosphatase to the Equilibrium Model. Parameter values derived from this fitting are: ΔG‡_cat, 57 kJ·mol⁻¹; ΔG‡_inact, 97 kJ·mol⁻¹; ΔH_eq, 86 kJ·mol⁻¹; T_eq, 333 K [2]. (C) The result of running a simulation of the Classical Model using the values of ΔG‡_cat and ΔG‡_inact derived from the fitting described above. The experimental data itself cannot be fitted to the Classical Model.