Used primarily in peptide synthesis, this compound acts as a protecting group for cysteine residues, ensuring selective reactions during the formation of peptide bonds. It is particularly valuable in the preparation of disulfide bridges, a critical feature in the structure of many proteins. The Npys group allows for efficient thiol-disulfide exchange reactions, enabling the controlled formation of these bridges. This makes it a key reagent in the development of peptides with specific biological activities, such as hormones, enzymes, and therapeutic agents. Additionally, it is employed in the study of protein folding and the stabilization of peptide-based drugs. Its application is essential in both research and industrial settings for creating complex peptide structures with high precision.