Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit (Fluorometric) (BN00925)

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  • Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit (Fluorometric) (BN00925)
  • Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit (Fluorometric) (BN00925)
  • Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit (Fluorometric) (BN00925)


ELISA Kit Technical ManualMSDS

Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit (Fluorometric)

Cytochrome P450 3A4 (CYP3A4, EC is a member of the cytochrome P450 monooxidase (CYP) family of microsomal xenobiotic metabolism enzymes. CYPs are membrane-bound hemeproteins responsible for Phase I biotransformation reactions, in which lipophilic drugs and other xenobiotic compounds are transformed to more hydrophilic products to facilitate excretion from the body. CYP3A4 is expressed in high levels in the liver and intestines, where it catalyzes oxidation of an extraordinarily wide variety of structurally distinct ligands. More than half of all small molecule drugs commonly used by humans are metabolized by CYP3A4. Inhibition of CYP3A4-mediated metabolism is a common cause of adverse drug/drug and drug/food interactions and toxicity. In addition, for drugs whose pharmacological activity requires metabolism from a pro-drug form, CYP3A4 inhibition can lead to decreased drug efficacy. Assay Genie's CYP3A4 Activity Assay Kit enables rapid measurement of native or recombinant CYP3A4 activity in biological samples such as liver microsomes. The assay utilizes a non-fluorescent CYP3A4 substrate that is converted into a highly fluorescent metabolite detected in the visible range (Ex/Em = 535/587 nm), ensuring a high signal-to-background ratio with little interference by autofluorescence. CYP3A4 specific activity is calculated by running parallel reactions in the presence and absence of the potent inhibitor Ketoconazole and subtracting any residual activity detected with the inhibitor present. The kit contains a complete set of reagents sufficient for performing 100 sets of paired reactions (in the presence and absence of inhibitor).

Figure: (a) Resorufin standard curve. One mole of resorufin corresponds to the metabolism of one mole of CYP3A4 substrate. (b) Reaction kinetics of fluorogenic substrate metabolism in human liver microsomes (0.05 mg/mL) at 37°C in the presence and absence of the CYP3A4 inhibitor Ketoconazole (the no inhibitor reaction contained a final concentration of 0.6% acetonitrile). (c) Specific activity of CYP3A4 in pooled human liver microsomes (0.05 mg/mL). Assays were performed according to the kit protocol.

Key Information Description

Product SKU



200 assays

Detection Method

Fluorescence (Ex/Em 535/587 nm)

Species Reactivity



  • Rapid assessment of native/recombinant CYP3A4 activity in lysates or microsomal fractions prepared from tissues or cells.
  • Screening of drugs and novel ligands for interaction with native/recombinant CYP3A4.

Features and Benefits

  • Simple, convenient, highly sensitive
  • Fluorescent assay enables determination of CYP3A4, CYP3A5 activity in a variety of biological samples
  • The substrate shows low background and a high signal-to-noise ratio
  • Kit includes CYP3A inhibitor ketoconazole and a stable, recombinant human CYP3A4 co-expressed with NADPH Reductase as a positive control

Kit Components

  • CYP3A4 Assay Buffer
  • Resorufin Standard (5 mM in DMSO)
  • CYP3A4 Inhibitor (Ketoconazole)
  • NADPH Generating System (100X)
  • Beta-NADP+ Stock (100X)
  • CYP3A4 Substrate
  • Recombinant Human CYP3A4

Storage Conditions


Shipping Conditions

Gel Pack


For Research Use Only! Not For Use in Humans.

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