Fmoc-HoLeu-OH is widely used in peptide synthesis as a building block for the incorporation of hydroxy leucine into peptide chains. Its Fmoc (fluorenylmethyloxycarbonyl) protecting group allows for selective deprotection during solid-phase peptide synthesis, enabling the stepwise assembly of peptides. This compound is particularly valuable in the synthesis of bioactive peptides and peptidomimetics, where hydroxy leucine plays a critical role in enhancing stability, solubility, or biological activity. It is also employed in the development of peptide-based drugs, protein engineering, and research focused on understanding protein structure and function. Additionally, Fmoc-HoLeu-OH is utilized in the preparation of peptide libraries for high-throughput screening in drug discovery.