Fluorescence polarization of green fluorescent protein (GFP). A strategy for improved wavelength discrimination for GFP determinations

The fluorescence of green fluorescent protein (GFP), present both within whole yeast cells and in protein exts. from yeast cells, has been obsd. to be significantly polarized. Fluorescence polarization is proposed as a useful technique to allow some discrimination between GFP fluorescence and that of other interfering species in cell or media matrixes, which have fluorescence bands that overlap those of GFP, which should lead to improved resoln. and limits of detection. The method has been tested by discriminating between the fluorescence of GFP in cell exts. and added fluorescein, both of which fluoresce brightly at the same wavelength. The flow-through instrumentation incorporating an argon-ion laser developed for this work is also described. [on SciFinder (R)]