Changzhou Smart-Lifesciences Biotechnology Co.,Ltd.

SMCC is a class of bifunctional coupling agents containing N-hydroxysuccinimide (NHS) and maleimide groups that bond compounds  containing amine and sulfhydryl groups, respectively. NHS reactive esters form amide bonds with primary amines at pH 7-9, while maleimides form stable thioether bonds with sulfhydryl groups at pH 6.5-7.5. In aqueous solutions, hydrolysis of NHS reactive esters (reaction with the amino group) is a competing reaction. The maleimide group is more stable than the NHS, but at pH greater than 7.5, it slowly hydrolyzes and loses its specificity for reacting with sulfhydryl groups. Consequently, the use of SMCC is usually performed at pH 7.2-7.5 and the NHS is allowed to react first. The cyclohexane ring in the SMCC structure reduces the rate of hydrolysis of maleimide group. It allows proteins to be lyophilized and stored for a period of time after modification with SMCC. This reagent is chosen for maleimide modification of many proteins.