N-(6-Maleimidocaproyloxy)succinimide

N-(6-Maleimidohexanoyloxy)succinimide (CAS No.: 55750-63-5), abbreviated as EMCS, is a heterobifunctional crosslinker commonly used in biomedical research. It can react with primary amines under buffered conditions at pH 7.5 to form stable amide bonds, and react with free thiols at pH 6.8 to form stable thioether bonds. Its unique structure makes it widely used in the preparation of enzyme immunoconjugates and hapten–carrier molecules, and it is particularly suitable for the synthesis of antibody–drug conjugates (ADCs). In experimental design, the working concentration and dosage of EMCS are typically adjusted according to specific research objectives and experimental conditions to ensure the efficiency and specificity of the crosslinking reaction. In addition, the aliphatic spacer arm of EMCS can stabilize the maleimide group prior to coupling, enhancing its stability in biological systems.