Used in bioconjugation and pharmaceutical research to link molecules with enhanced solubility and reduced immunogenicity. The long PEG chain improves water solubility and extends circulation time in vivo, making it valuable in drug delivery systems. Commonly employed to spacer arms in peptide and protein modifications, allowing better binding accessibility. Also applied in the synthesis of PEGylated compounds for diagnostic imaging and targeted therapies. Its terminal carboxylic acid group enables easy coupling to amines via standard EDC/NHS chemistry, while the Boc-protected amine allows for selective deprotection and further functionalization.