If you have fluorescein (10-100nM) in your lab, you could measure the effect of varying the amount of glycerol (0 to 100%) on the fluorescence anisotropy of fluorescein in a phosphate buffer. The anisotropy should increase with increasing concentration of glycerol. Fluorescein by itself in a buffer should have very very low anisotropy.
Or you could do a fluorescence quenching experiment by titrating potassium iodide (0 to 500mM KI) into a fluorescein solution. The anisotropy should increase with increasing KI. (because of decrease in fluorescence lifetime) I have never done the above experiments, as I always had a macromolecular binding assay that worked. But you could give the above recipe a try. It should work. From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Huiming Li Sent: Thursday, March 08, 2012 2:21 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] off topic: fluorescence polarization positive control Hi all, Sorry for the off topic question. Could someone suggest a positive control for FP assay? I am developing this assay and would like to use it for trouble shooting an instrument. Thanks, Huiming Li
