4-[2,2-bis[(p-tolylsulfonyl)-methyl]acetyl]benzoic acid-N-hydroxy succinimidyl ester

Bis-sulfone NHS Ester is a bis-alkylating labeling reagent that is selective for the cysteine sulfur atoms from a native disulfide. These reagents undergo bis-alkylation to conjugate both thiols derived from the two cysteine residues of a reduced native disulfide bond such as the interchain disulfide bonds of an antibody. The reaction results in covalent rebridging of the disulfide bond via a three carbon bridge leaving the protein structurally intact.