This chemical is widely used in peptide synthesis, particularly in the preparation of biotinylated peptides for research and diagnostic purposes. Its structure, featuring an Fmoc-protected lysine residue linked to biotin via a PEG4 spacer, makes it ideal for introducing biotin into peptides without disrupting their biological activity. The biotin tag allows for easy detection, purification, and immobilization of peptides using streptavidin-based systems, which are commonly employed in assays like ELISA, Western blotting, and affinity chromatography. The PEG4 spacer enhances flexibility and accessibility of the biotin moiety, improving binding efficiency. This compound is especially valuable in proteomics, drug discovery, and the development of targeted therapeutics, where precise labeling and tracking of peptides are critical.