Predictor™ hERG Fluorescence Polarization Assay Kit - FAQs

No, the Predictor hERG Membranes are not suitable for radioligand binding.
These membranes contain extremely high levels of hERG channel protein. Radioligand binding assays on these membranes would require either abnormally high concentrations of radioligand or severe dilutions of the membrane preparation, which tend to have a deleterious effect on hERG channel conformation and stability.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

-No assay window: Check that your instrument is designed to do FP experiments.
-Poor discrimination between the minimum and maximum mP Control (both include the receptor): This may be an indication of the quality of the receptor. Do not make single use aliquots of the receptor or store diluted.
-The type of microplate is critical: Please see if the protocol specifies untreated polystyrene or NBS-coated plates. If the plate binds the fluorescent substrate, it cannot freely rotate and the mP reading will always be high. White plates cannot be used for FP assays. Avoid the use of silanized pipette tips and vials.
-The “No Receptor Control' (free Fluormone/Tracer) should have much higher RFU values compared to buffer alone. If not, there is a problem with the instrument setup or less commonly with the Fluormone/Tracer.
-If the free Fluormone/Tracer mP value is greater than 100 mP or negative, please refer to the user manual for your instrument and reset the G factor.

Find additional tips, troubleshooting help, and resources within our Drug Discovery & Development Support Center.

For FP assays, plate readers must specifically have FP built in. Please see our instrument compatibility portal (http://www.thermofisher.com/us/en/home/industrial/pharma-biopharma/drug-discovery-development/dd-misc/instrument-compatibility-portal.html).

Find additional tips, troubleshooting help, and resources within our Drug Discovery & Development Support Center.

We offer a FP One-Step Reference Kit (https://www.thermofisher.com/order/catalog/product/P3088) to detect in green (Ex/Em = 488/535 nm) and red (Ex/Em = 525/590 nm) emission ranges, suitable for the PolarScreen Green and Red Assays. The alternative is to perform the Controls in the respective assay kit prior to performing the actual assay using test compounds.

Find additional tips, troubleshooting help, and resources within our Drug Discovery & Development Support Center.