N-Ethylmaleimide is widely used in biochemical research as a selective reagent to modify cysteine residues in proteins. It effectively blocks thiol groups, making it valuable for studying enzyme mechanisms and protein functions by inhibiting cysteine-dependent enzymes. This property is particularly useful in understanding protein structure and interactions. Additionally, it is employed in the study of membrane transport processes, where it inhibits certain ATPases by reacting with their cysteine residues. In cell biology, N-Ethylmaleimide is used to investigate vesicular trafficking and fusion events, as it disrupts SNARE protein function. Its ability to alkylate thiols also makes it a tool for probing redox-sensitive processes in cells.