realizes has_specified_input role of has role immunoglobulin complex, circulating evaluant role antibody binding detection by fluorescence quenching A binding assay in which affinity is measured by detecting a change in fluorescence (usually quenching) that occurs upon binding of the antibody to the ligand. The fluorescent signal that is affected by binding is either from an exogenous fluorophore attached to the ligand, or is the intrisic fluorescence of aromatic (tryptophan) residues on the binding site of the antibody (no conjugated fluorophore necessary) or, less commonly, on the ligand binding region (epitope). fluorescence quenching binding assay