Bis[2-(succinimidooxycarbonyloxy)ethyl] sulfone functions as a bifunctional amine-reactive crosslinker, facilitating the conjugation of β-endorphin with opioid receptors. It is utilized as the sulfone derivative of bis(2-hydroxyethyl) succinimide (BES) and plays a critical role in peptide and protein synthesis, as well as in studying enzyme reaction mechanisms.