Contaminating Proteins for Fluorescence Polarization Assay

[David Liu]

I am handing over some protein samples to a collaborator to do a fluorescence polarization assay to determine binding affinity as a check for activity of a protein that I'm modifying. Using quantitative Western or Coomassie Blue stain, I can determine the concentration of just the protein of interest in a mixture. My question is whether contaminating proteins (carrier protein, enzyme for modifications, etc) will affect the readout of the fluorescence polarization reading. I will lose a significant amount of modified protein if I purify it from the mixture, so I'm wondering if the "dirty" prep would work for fluorescence polarization if I know the concentration of the protein I'm interested in.

Thanks