AAT Bioquest

What could cause IC50 or EC50 values to differ between biochemical and cell-based assays?

Posted February 13, 2020

There are a couple of explanations for why discrepancies may occur between IC50 and EC50 values derived from biochemical and/or cell based assays. One explanation is that the compound may either be unable to penetrate the cell membrane or the cell may be pumping the compoound out. Another explanation is that compound is targeting other non-specific targets that could affect these values significantly.
Additional resources

IC50 calculator

EC50 calculator