Used primarily in bioconjugation and drug delivery systems, it serves as a linker molecule for attaching functional groups or therapeutic agents to biomolecules. Its disulfide bond (SS) allows for controlled release in reducing environments, such as inside cells. The Boc (tert-butoxycarbonyl) group provides protection for amines during synthesis, ensuring selective reactions. The PEG (polyethylene glycol) spacer enhances solubility and reduces immunogenicity, making it suitable for biomedical applications. Propargyl groups enable click chemistry, facilitating efficient and specific coupling reactions. Commonly employed in targeted cancer therapies, antibody-drug conjugates, and peptide modifications.