It contains the amide functional group, but more importantly it is an alkene that is reactive toward thiols and is commonly used to modify cysteine residues in proteins and peptides.

NEM is an irreversible inhibitor of all cysteine peptidases, with alkylation occurring at the active site thiol group (see schematic).

NEM activates ouabain-insensitive Cl-dependent K efflux in low-K sheep and goat red blood cells.

[5] This discovery contributed to the molecular identification of K–Cl cotransport (KCC) in human embryonic cells transfected by KCC1 isoform cDNA, 16 years later.

[6] Since then, NEM has been widely used as a diagnostic tool to uncover or manipulate the membrane presence of K–Cl cotransport in cells of many species in the animal kingdom.