This compound is widely used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It is an Fmoc-protected amino acid derivative featuring a hydrophilic polyethylene glycol (PEG₆) spacer and a free carboxylic acid group. The carboxylic acid allows standard coupling to the growing peptide chain, while the Fmoc group provides orthogonal protection for selective deprotection, preventing unwanted side reactions. The PEG spacer enhances solubility in aqueous solutions, making it useful for synthesizing peptides with improved water solubility. Additionally, it is employed in the development of peptide-based drugs, bioconjugates, and biomaterials, where controlled release and stability are critical. Its application also extends to the study of protein-protein interactions and the design of peptide-based probes for biochemical research.