Nepsilon-(2,4-Dinitrophenyl)-L-lysine Hydrochloride is primarily used in biochemical and immunological research. It serves as a hapten in the development of antibodies, particularly for studying immune responses and antigen-antibody interactions. The compound is also utilized in enzyme-linked immunosorbent assays (ELISA) and other immunoassays to detect and quantify specific proteins or antibodies. Additionally, it aids in the investigation of protein modifications and the role of lysine residues in protein structure and function. Its application extends to the study of molecular recognition and binding mechanisms in biological systems.