3-Maleimidopropionic acid N-hydroxysuccinimide (NHS) ester is a membrane-permeable, non-cleavable bifunctional crosslinker. It contains an amine-reactive succinimidyl ester and a thiol-reactive maleimide group.
The NHS residue can be attached to almost any primary or secondary amine group of proteins, peptides, or small molecule amines. The maleimide moiety provides easy attachment to proteins and peptides via SH-residues of cysteine and to other thiolated molecules, such as thiol-containing oligonucleotides.
This reagent is also used for in situ synthesis of chemically unstable azide-PEG4-maleimide.