The P450-Glo™ CYP3A4 Assays provide a homogeneous, luminescent method for measuring cytochrome P450 CYP3A4 activity. The assays are designed to measure the activities of P450s from recombinant and native sources and for testing the effects of analytes such as drugs and new chemical entities on P450 activities. These luminescent assays exhibit exquisite sensitivity, low background signals and broad dynamic range.
P450-Glo™ Assays employ luminogenic P450 substrates that are derivatives of beetle luciferin, a substrate for luciferase enzymes. The derivatives are not substrates for luciferase but are converted by P450s to luciferin, which in turn reacts with luciferase to produce light that is directly proportional to the activity of the P450.
The P450-Glo™ Assays generate a "glow-type" luminescent signal, produced using derivatized luciferins as P450 substrates and a recombinant stabilized luciferase (Ultra-Glo™ Luciferase) coupled with a proprietary buffer system. The half-life of the luminescent output is greater than two hours, eliminating the need for luminometers with injectors and allowing batch plate processing. The formulation also minimizes the incidence of false positives due to inhibition of luciferase by analytes when screening for cytochrome P450 inhibitors.
Dimethyl sulfoxide (DMSO), a common solvent used to solubilize chemical compounds, can significantly inhibit the activity of the 3A4 isoform of cytochrome P450, even at low concentrations (<0.1%).The P450-Glo™ CYP3A4 System (Luciferin-PPXE) DMSO-Tolerant Assay is specifically designed to tolerate DMSO in the 3A4 reaction. The assay exhibits little to no change in the signal-to-background ratio in the presence of 0.2% DMSO compared to a no-DMSO control.