Used in pharmaceutical and biotechnology research as a hydrophilic linker to modify peptides, proteins, and drug molecules. Enhances solubility and stability in aqueous environments, reduces immunogenicity, and prolongs circulation time in vivo. Commonly applied in the development of PEGylated therapeutics and conjugation strategies where controlled release or improved pharmacokinetics is desired. The methyl ester end group allows for further functionalization or cleavage under mild conditions, making it suitable for prodrug design and targeted delivery systems.