What is the ED50 Range and how is it compared to specific activity in units/mg?
We supply recombinant cytokines in g (or mg) with a specific ED50 range rather than as specific activity in units per vial. The ED50 is defined as the cytokine concentration at which the bioassay activity is 50% of the maximum response. Bioassay is a measurement of biological response, such as cell proliferation assay, functional ELISA or an enzymatic assay, to a specific protein. Due to the variable nature of bioassays, the same cytokine preparation may not give you the same ED50 value at different occasions. In particular, any variation in a bioassay condition such as cell densities, age or even passage numbers may lead to variable results. Humanzyme report typical ED50 range on datasheet for a given cytokine. ED50 is accurate only when the cytokine dose-response curves are sigmoidal shape.
