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 crosslinkers for these applications.

BS(PEG) is a bis-succinimide ester-activated PEG compound used for crosslinking between primary amines (—NH2) in proteins and other molecules. The N-hydroxysuccinimide ester (NHS) groups at either end of the PEG5 spacer react specifically and efficiently with lysine and N-terminal amino groups at pH 7 to 9 to form stable amide bonds.

Thermo Scientific No-Weigh products are specialty reagents provided in a pre-aliquoted format. The pre-weighed packaging prevents the loss of reagent reactivity and contamination over time by eliminating the repetitive opening and closing of the vial. The format enables use of a fresh vial of reagent each time, eliminating the hassle of weighing small amounts of reagents and reducing concerns over reagent stability.

Features of BS(PEG)5:
• Reactive groups: sulfo-NHS ester (both ends)
• Reactive towards: amino groups (primary amines)
• Water-soluble; compare to non-pegylated BS3 (also soluble) and DSS (water-insoluble)
• Membrane-impermeable, allowing for cell surface labeling
• Irreversibly crosslink proteins or peptides by flexible PEG spacer arms
• Polyethylene glycol spacer arms help maintain conjugate solubility
• Pure compound with defined structure and molecular weight, ensuring reproducible protein-modification effects
• PEG spacer provides unique advantages, including increased stability, reduced tendency toward aggregation and reduced immunogenicity
• Ideal for small molecule or peptide conjugations