Cellular proteins and other nucleophiles

Cellular proteins and other nucleophiles represent a broad and heterogeneous collection of endogenous molecules that possess electron-rich functional groups, such as thiols in cysteine residues, amines in lysine, and nitrogenous bases in DNA. In a pharmacological context, this category is not a single discrete target but rather a collective site of action for highly reactive electrophilic drugs and metabolites [1][2]. Many cytotoxic chemotherapeutic agents, specifically alkylating agents, function by forming irreversible covalent bonds with these nucleophilic sites, thereby disrupting DNA replication and protein function to induce cell death in rapidly dividing cancer cells [3]. However, because these nucleophiles are ubiquitous throughout the body, such interactions are often non-specific, leading to significant side effects and organ toxicity, such as the depletion of protective glutathione or the modification of essential metabolic enzymes [4]. The term is frequently used in toxicology to describe the mechanism by which reactive intermediates, like the acetaminophen metabolite NAPQI, cause cellular damage [5]. Consequently, while critical to the efficacy of certain classes of drugs, this group is generally considered too broad to be classified as a specific therapeutic target in modern precision medicine.

Other names

Cellular nucleophilesBiological nucleophilesEndogenous nucleophilesProtein thiolsNucleophilic targets

Covalent modification (alkylation, acylation, or arylation) of nucleophilic functional groups such as sulfhydryl (thiol), amino, hydroxyl, and phosphate groups on cellular macromolecules.