Electrophilic small molecules

Electrophilic small molecules are a diverse class of chemical entities characterized by their ability to form covalent bonds with nucleophilic residues on biological macromolecules (Singh et al., 2011, Nature Reviews Drug Discovery). In drug discovery, these molecules are typically designed as covalent inhibitors containing reactive functional groups, or warheads, such as Michael acceptors, which target specific amino acids like cysteine, serine, or lysine (Bauer, 2015, Journal of Medicinal Chemistry). While historically associated with non-specific toxicity and idiosyncratic drug reactions, modern medicinal chemistry has refined these molecules to achieve high selectivity and prolonged duration of action (Baillie, 2016, Chemical Research in Toxicology). They are prominently used to target oncogenic drivers, such as the KRAS G12C mutation or Bruton's tyrosine kinase (BTK), and to activate cytoprotective pathways like the Keap1-Nrf2 system (Dinkova-Kostova et al., 2018, Free Radical Biology and Medicine). Despite their therapeutic utility, electrophilic molecules pose unique safety challenges, including the potential for haptenization and subsequent immune-mediated hypersensitivity (Popovic et al., 2006, Chemical Research in Toxicology). Their reactive nature necessitates careful optimization of the warhead reactivity to ensure a balance between potency and off-target safety. Consequently, they are considered a chemical class of ligands rather than a specific biological target or receptor.

Other names

Covalent inhibitorsElectrophilic warheadsMichael acceptorsReactive metabolitesCovalent modifiers

Formation of a stable covalent bond with nucleophilic amino acid residues, such as the thiol group of Cysteine or the amino group of Lysine, on a target protein to achieve irreversible or slowly reversible modulation of protein function.