Used in peptide synthesis as a protected amino acid derivative, particularly for introducing methionine residues with defined stereochemistry. The Fmoc group allows for mild base-labile protection, compatible with solid-phase synthesis. Enables stepwise construction of peptides in automated synthesizers. The methionine side chain (methylthio group) imparts hydrophobic properties, facilitating membrane penetration in the resulting peptides. Commonly applied in research settings for producing custom peptides used in drug development, biochemical assays, protein studies, vaccine development, and enzyme inhibitors. Its chiral purity ensures correct folding and biological activity of synthesized peptides.