A europium chelate is covalently conjugated on lysines of the anti-HA mouse monoclonal antibody (clone HA.C5). The molar ratio between europium and antibody in different lots is ~5 - 10. The europium-anti-HA mouse monoclonal antibody recognizes HA-tagged proteins/peptides and can serve as the donor in TR-FRET assays that offer a sensitive tool in monitoring molecular proximity, post-translational modifications, enzyme activity, and protein abundance. The acceptor is far-red fluorescent dyes, such as Cy5.
