This compound is the Fmoc-protected derivative of L-glutamic acid, specifically (S)-Fmoc-Glu(Fmoc)-OH, where the α-amino group is protected with a fluorenylmethoxycarbonyl (Fmoc) group and the side-chain γ-carboxylic acid is protected as an Fmoc ester. It serves as a key building block in solid-phase peptide synthesis (SPPS) for incorporating glutamic acid residues into peptide chains. The Fmoc protections prevent unwanted side reactions: the α-Fmoc shields the amine functionality to enable controlled, stepwise peptide assembly, while the side-chain Fmoc ester protects the carboxylic acid. Both Fmoc groups are orthogonally removable under mild basic conditions (e.g., using piperidine in DMF), making this compound highly suitable for efficient SPPS. It is particularly valuable in producing complex peptides and proteins for pharmaceutical research, drug development, and biochemical studies, ensuring high purity and precision in synthesizing biologically active molecules.