Figure 1.

Comparison of the free energy profiles Δg for a given reaction in a protein (Δg_p^‡) and in water (Δg_w^‡). The figure represents these free energy profiles in the absence (Δg) and presence (Δg′) of constraints for the movement of the reacting fragments. Note that Δg_p^‡ corresponds approximately to k_cat/K_m (it is given by ΔG_bind + Δg_cat^‡). The figure uses the notation of L for ligand rather than S for substrate to prevent confusion with the symbol S used for entropy.