Cross linkers are used for the identification of near-neighbour protein relationships and ligand-receptor interactions. Homobifunctional, amine-reactive NHS esters or imidates, and heterobifunctional, amine-reactive, photoactivatable phenyl azides are the most commonly used cross linkers for these applications.

• • Reactive groups: maleimide (both ends)
• • Reactive towards: sulfhydryl groups
• • Long, pegylated, sulfhydryl-to-sulfhydryl crosslinkers, composed of maleimide groups and 3-unit polyethylene glycol spacer arm
• • PEG spacers provide unique advantages, including enhanced solubility, increased stability, reduced tendency toward aggregation and reduced immunogenicity
• • Pure compounds with defined structure and molecular weight, ensuring reproducible protein-modification effects
• • Ideal for small molecule or peptide conjugations

Homobifunctional cross linkers are used in one step reactions while the heterobifunctional cross linkers are used in two-step sequential reactions, where the least labile reactive end is reacted first. Homobifunctional cross-linking agents have the tendency to result in self-conjugation, polymerisation, and intracellular cross-linking.

BM(PEG) is a bismaleimide-activated PEG compound for crosslinking between sulfhydryl (—SH) groups in proteins and other thiol molecules. The maleimide groups at either end of the PEG3 spacer react specifically and efficiently with reduced sulfhydryls at pH 6,5 to 7,5 to form stable thioether bonds.