FIG. 1.

Molecular-weight-dependent polarization for a protein-bound fluorophore with fluorescence lifetime (τ) of 4, 50, and 400 ns. The curves are based on Eqs. [1] and [3] assuming $\overline{v}+h=1.9$ for the proteins in aqueous solution at 20°C with a viscosity of 1 cP. The arrows and bars indicate M_rs of the antigen (Ag) and antibodies (Ab) and complexes discussed in the text.