N-ethylmaleimide

N-EthylmaleimideN-Ethylmaleimide (NEM) is an organic compound made from the maleic acid. It has the functional group amide however, it’s an alkene that reacts with thiols and is frequently used to alter cysteine residues found in proteins and peptides.

N-ethylmaleimide (NEM) has been found to increase severalfold in the sensitization to ouabain K+ efflux but without altering Na+ efflux in heterozygous and homozygous lower K+ (LK) red cells from sheep but not triggering any response within (HK) cells. Of eight preparations of L-antibody (anti-L) that have been shown to reduce K+ efflux, the control Six showed no effect, while two decreased a NEM-mediated K+ flow. Sulfhydryl groups controlled through the LK gene might control a portion of the ouabain-insensitive permeability.