Used extensively in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS), where it serves as a linker or spacer molecule. Its polyethylene glycol (PEG) chain provides solubility and flexibility, facilitating the synthesis of long or complex peptides. The Fmoc group acts as a protective group for the amine, allowing selective deprotection during synthesis. The carboxylic acid end enables conjugation to resins or other molecules, making it valuable for creating peptide-drug conjugates or bioconjugates. It is also employed in the development of peptide-based therapeutics, diagnostics, and biomaterials due to its biocompatibility and ability to enhance stability and bioavailability. Additionally, it is utilized in research for studying protein-protein interactions and designing peptide-based probes or sensors.