FRET assay detecting multiple epitope-tagged protein. Dilutions of a recombinant protein containing multiple different epitope tags were incubated with antibodies labeled with either a europium chelate (donor) or DyLight®650 (acceptor). The assay was performed in a white 384 well microplate with a total volume per well of 20 µl, with all reagent dilutions being made in 25 mM Tris, pH 7.5, 100 mM NaCl, 0.1% BSA, and 0.05% Tween-20. Europium labeled donor antibody was at a final concentration in well of 2 nM, while the DyLight®650 labeled acceptor antibody was at 25 nM. Plates were read after 1 hour, measuring energy transfer signal at 665nm using a Perkin Elmer Victor³V time-resolved multilabel reader.