Boc-Orn(Z)-OSu is a protected and activated form of ornithine, specifically N^α-Boc-N^δ-Z-ornithine N-hydroxysuccinimide ester. It is widely used in peptide synthesis to incorporate the ornithine residue into peptide chains. The Boc (tert-butyloxycarbonyl) group protects the α-amino group, the Z (benzyloxycarbonyl) group protects the δ-amino group on the side chain, and the OSu active ester enables efficient and racemization-free coupling to the N-terminus of growing peptides. This reagent is essential in both solid-phase and solution-phase peptide synthesis, supporting the precise construction of complex peptide sequences for pharmaceutical research, bioactive peptide development, and biochemical studies.