N-Ethyl Maleimide

N-Ethyl Maleimide (NEM) is a chemical compound that is commonly used in biochemistry and molecular biology research. It is a reactive compound that can modify sulfhydryl (SH) groups on proteins, making it a useful tool for studying protein structure and function. NEM is a small molecule that can easily penetrate cell membranes, allowing it to react with SH groups on intracellular proteins. NEM is typically used in experiments that involve the study of protein-protein interactions or the identification of active sites on proteins. It is often used in combination with other reagents, such as disulfide reducing agents, to selectively modify specific SH groups on proteins. NEM is also commonly used in protein cross-linking experiments to probe the structure of protein complexes. Chemically, NEM is a white crystalline solid that is soluble in organic solvents such as ethanol and dimethyl sulfoxide (DMSO). It has a molecular weight of 141.13 g/mol and a melting point of 41-43°C. NEM is reactive towards SH groups due to the presence of a Michael acceptor moiety, which undergoes nucleophilic addition reactions with SH groups. It is important to handle NEM with care, as it can be toxic if ingested or inhaled. It should be stored in a cool, dry place and handled in a fume hood to avoid exposure to vapors. Overall, NEM is a valuable tool for studying protein structure and function in a variety of experimental settings.