Mono-sulfone NHS Ester

Mono-sulfone is a thiol-specific labeling reagent that undergo alkylation to generate a thio-ether bond between the protein and mono-sulfone activated reagent. Once mono-sulfone reagent is conjugated to a protein or peptide, exchange reactions leading to deconjugation can be easily avoided by treating the conjugate with a mild reducing agent in a way analogous to the process used for conjugation reactions involving reductive amination.