Nα,Nε-Bis(2,4-dinitrophenyl)-L-lysine is a derivatized form of L-lysine in which both the α-amino and ε-amino groups are substituted with 2,4-dinitrophenyl moieties. It serves as a key reference standard in amino acid analysis, particularly in chromatographic methods such as paper chromatography, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC). This compound is used to identify and quantify lysine residues in protein hydrolysates following derivatization with Sanger's reagent (2,4-dinitrofluorobenzene). Its yellow color and specific Rf values make it valuable for structural studies of proteins, peptide mapping, and validation of analytical protocols in biochemistry. Additionally, it aids in the development and calibration of assays for detecting post-translational modifications involving lysine.