N6-[(2-Azidoethoxy) carbonyl]-L-lysine (UAA crosslinker 1) is a click chemistry-reactive amino acid derivative. N6-[(2-Azidoethoxy) carbonyl]-L-lysine mediates the generation of antibody-drug conjugates (ADCs). N6-[(2-Azidoethoxy) carbonyl]-L-lysine is used for site-specific incorporation into recombinant proteins, or for synthesizing chemical probes and tools for biological research[1].