Used in bioconjugation and protein modification, it enables the attachment of molecules to thiol groups in proteins or peptides. The PEG spacer enhances solubility and reduces steric hindrance, improving reaction efficiency. Commonly applied in drug delivery systems to conjugate therapeutic agents with targeting molecules. Also utilized in biochemical research for labeling and tracking proteins in cellular studies. Its oxyamine group allows for specific reactions with aldehydes or ketones, facilitating site-specific modifications.