STUDY ON POLARIZED FLUORESCENCE DECAY OF RABBIT GAMMA-GLOBULIN CONJUGATED WITH FLUORESCEIN ISOTHIOCYANATE

The decay of the polarized components, I∥ and I⊥, of the fluorescence of rabbit γ-globulin conjugated with fluorescein isothiocyanate was studied. The decay of the difference I∥-I⊥ changed with the average number, υ, of fluorophores per protein molecule. This result was attributed to energy transfers between fluorophore attached to the same molecule. The extrapolated value for ν = o gives a relaxation time ρ{variant}h = 57 nsec in agreement with the value previously obtained with a 5-dimethylaminonaphthalene-1-sulfonyl conjugate. The presence of free internal rotation in the molecule was confirmed. © 1969.