N-Ethylmaleimide is widely used in biochemical research as a thiol-reactive reagent. It specifically targets and modifies cysteine residues in proteins, making it a valuable tool for studying protein structure and function. This compound is often employed to inhibit enzymes that rely on cysteine for their activity, helping researchers understand enzymatic mechanisms. Additionally, it is used in proteomics to block disulfide bond formation, ensuring accurate analysis of protein samples. Its ability to irreversibly bind to thiol groups also makes it useful in labeling and tracking proteins in various experimental setups.