Kinetic isotope effects for studying post-translational modifying enzymes

Abstract

The ongoing development of new experimental approaches for the measurement of isotope effects is improving our understanding of the physical and chemical changes that occur during biological catalysis. Biological catalysis involves numerous steps that include binding, conformational changes, chemical catalysis and product release. The critical points on the free energy surface for biologically catalyzed reactions include all bound intermediates and the intervening transition states. Isotope effects can be used to investigate both intermediate (equilibrium isotope effects) and transition state (kinetic isotope effects) structures along the reaction coordinate. This review details new techniques for measuring isotope effects and provides several examples of their use in solving transition state structures for post-translational modifying enzymes.