Chemical and Computational Methods for the Characterization of Covalent Reactive Groups for the Prospective Design of Irreversible Inhibitors

Interest in drugs that covalently
modify their target is driven
by the desire for enhanced efficacy that can result from the silencing
of enzymatic activity until protein resynthesis can occur, along with
the potential for increased selectivity by targeting uniquely positioned
nucleophilic residues in the protein. However, covalent approaches
carry additional risk for toxicities or hypersensitivity reactions
that can result from covalent modification of unintended targets.
Here we describe methods for measuring the reactivity of covalent
reactive groups (CRGs) with a biologically relevant nucleophile, glutathione
(GSH), along with kinetic data for a broad array of electrophiles.
We also describe a computational method for predicting electrophilic
reactivity, which taken together can be applied to the prospective
design of thiol-reactive covalent inhibitors.