Used in peptide synthesis as a protected amino acid building block, enabling stepwise construction of complex peptides with precise sequence control. The Fmoc group provides temporary protection for the alpha-amine, allowing selective deprotection under mild basic conditions while the HCl salt form enhances stability and handling. Commonly applied in solid-phase peptide synthesis (SPPS) for pharmaceutical research, including the development of peptide-based drugs and biomaterials. Its methyl ester side chain protection supports selective deprotection strategies in branched or cyclic peptide architectures.