This chemical, featuring a maleimide group linked via PEG3 chains to a sulfone moiety and a PEG3-t-butyl ester, is primarily utilized in the field of bioconjugation and drug delivery systems. The maleimide enables site-specific conjugation to thiol groups on cysteine residues, while the sulfone group provides stable linkages, making it highly effective in creating conjugates between molecules, particularly in the development of antibody-drug conjugates (ADCs). The PEG moieties enhance solubility and reduce immunogenicity, and the t-butyl ester group serves as a protective function during synthesis, which can be easily removed to activate the molecule for further reactions. This compound is also employed in the modification of peptides and proteins to improve their pharmacokinetic properties, making it a valuable tool in therapeutic applications.