Heavy atom labeled nucleotides for measurement of kinetic isotope effects

•Isotopically labeled nucleotides enable kinetic isotope effect measurements on chemical reactions involving nucleic acids.•State-of-the-art synthetic methods allow access to a variety of site-specifically labeled nucleotides.•A survey of isotope effect studies employing labeled nucleotides underscores their value in interrogating enzymatic transition states.•Isotope effect analysis provides a powerful strategy to investigate RNA catalysis

Experimental analysis of kinetic isotope effects represents an extremely powerful approach for gaining information about the transition state structure of complex reactions not available through other methodologies. The implementation of this approach to the study of nucleic acid chemistry requires the synthesis of nucleobases and nucleotides enriched for heavy isotopes at specific positions. In this review, we highlight current approaches to the synthesis of nucleic acids enriched site specifically for heavy oxygen and nitrogen and their application in heavy atom isotope effect studies. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment.