Isotope Methods in Catalysis – Biological

Abstract

Isotopic methods in the study of biocatalysis are chiefly used to characterize the mechanisms by which enzymes catalyze their target reactions. The techniques in use include tracer methods, by which the positions of individual atoms in a starting molecule are traced in downstream intermediates or products; exchange methods, in which isotopic mixing between distinct pools such as the solvent and enzyme‐bound intermediates is measured in order to test mechanistic hypotheses; and kinetic isotope effects, in which the relative rates of reaction of different isotopes of the same element are measured to identify rate‐limiting steps and determine transition‐state structures and other mechanistic information. Tracer and exchange methods are illustrated but, not being subject to easy generalization, are not treated in detail. The bulk of the article is devoted to kinetic isotope effects in the study of biocatalysts.