Thermo Scientific Pierce Sulfo-SMPB is a water-soluble amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a medium-length aromatic spacer arm (11.6 angstroms).

Features of Sulfo-SMPB:

• Reactive groups: sulfo-NHS ester and maleimide
• Reactive towards: amino and sulfhydryl groups
• Extended chain length limits steric hindrance
• Non-cleavable
• Water-soluble (compare to SMPB)
• Membrane impermeable, allowing for cell surface labeling

Product References:
Crosslinker Application Guide -- search for recent literature references for this product

Related Products
SMPB (succinimidyl 4-(p-maleimidophenyl)butyrate)