DSS is a homobifunctional amine-specific protein crosslinking reagent based on NHS-ester reactive groups for selective conjugation of primary amines.DSS contains two NHS ester groups at both ends of a 8-carbon spacer that readily react towards primary amines at pH 7-9.DSS is not water soluble and must be dissolved in an organic solvent such as DMSO or DMF prior to use. DSS is membrane permeable and can be used for the crosslinking of intracelular proteins