Z-D-Lys-OH is primarily used in peptide synthesis, particularly in the production of custom peptides for research purposes. It serves as a protected form of lysine, ensuring the amino group remains intact during the synthesis process. This compound is valuable in creating peptides with specific sequences, which are essential for studying protein interactions, enzyme functions, and biological pathways. Additionally, it is utilized in the development of peptide-based drugs and therapeutic agents, where precise amino acid incorporation is critical. Its application extends to biochemical assays and structural studies, aiding in the understanding of peptide behavior and properties.