Fmoc-Lys(Boc)-OH is widely used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It serves as a key building block for introducing lysine residues into peptide chains. The Fmoc (9-fluorenylmethoxycarbonyl) group protects the amino group during synthesis, while the Boc (tert-butyloxycarbonyl) group safeguards the side-chain amino group of lysine. This dual protection ensures selective deprotection and controlled peptide chain elongation. It is essential in producing peptides for research, pharmaceuticals, and biotechnology, including the development of therapeutic peptides, vaccines, and diagnostic tools. Its stability and compatibility with SPPS protocols make it a reliable choice for synthesizing complex peptides with high precision.