Used as a protected amino acid derivative in peptide synthesis, enabling selective coupling reactions by blocking the epsilon amine group of lysine. The Z (benzyloxycarbonyl) group provides compatibility with various coupling agents and allows for mild deprotection conditions. The benzyl ester protects the carboxylic acid function, while the benzenesulfonate salt enhances solubility and crystallinity, facilitating purification and handling in solid-phase or solution-phase peptide assembly. Commonly applied in the preparation of biologically active peptides and pharmaceutical intermediates.