Transition-State Interactions Revealed in Purine Nucleoside Phosphorylase by Binding Isotope Effects

摘要

Enzymatic transition-state (TS) analogues capture the lowered activation energy for catalysis as binding energy and TS formation has been explained in both dynamic and thermodynamic terms. Thermodynamic interpretation of catalysis and TS analogue binding proposes tight binding of reactants at the TS. This binding is converted directly into binding energy of TS analogues. The dynamic interpretation of catalysis proposes formation of the TS by a coordinated dynamic excursion of the protein that does not require tight binding at the TS.