Interrogating CD38 & PARG with Transcreener's ADPR Assay

Enzolution™ CD38 Assay System

The Enzolution CD38 Assay System includes CD38 (Cluster of differentiation 38) enzyme, NAD+, assay plates, and buffers required for a CD38 reaction to produce ADPR. The Transcreener ADPR Assay (sold separately) uses coupling enzyme to convert ADPR to AMP, which is detected using a far-red, competitive assay to measure enzymatic activity.

CD38 inhibitors continue to be sought after to combat a plethora of illnesses, including cancer and inflammatory-related diseases. The Enzolution CD38 Assay System, when used with the Transcreener ADPR Assay Kit, provides all reagents required to screen and profile CD38 inhibitors.

The Transcreener ADPR Assay is not included in the Enzolution Assay System but is available for separate purchase through BellBrook Labs. For ADPR assay ordering information, please view Transcreener ADPR Assay.

The Comprehensive Approach to Measure CD38 Enzymatic Activity

Enzolution CD38 Assay System Schematic

Enzolution Assay System includes enzyme, substrate, plates & buffer for the CD38 reaction. Transcreener's ADPR Assay measures ADPR produced.

An Outline of the Complete Protocol

The enzyme reaction is run in the presence of coupling enzyme, so that ADPR is converted to AMP in real time. After the enzyme reaction incubation is complete, AMP detection reagents are added along with EDTA to quench the coupling enzyme. 

Complete Outline of CD38 with ADPR Assay

Robust Assay Yields Quality Data

The Enzolution Assay System used with the Transcreener ADPR assay produces robust results amenable to HTS. Z' measurement using optimized CD38 assay conditions (n=16). Z' = 0.93.

CD38 Assay Produces Robust Data

Detection of CD38 Under Initial Velocity

Conversion of raw data to ADPR formed using a standard curve demonstrates assay linearity. The enzyme buffer included 50 mM Tris (pH 7.5), 10 mM MgCl2, 0.001% BSA, and 0.01% Brij-35. The CD38 enzyme reaction took place for 60 minutes at 30°C. The Detection Mix was added and incubated for 90 minutes at room temperature and read with a CLARIOstar plate reader. At 0.012 nM CD38, about 1.5 μM ADPR was produced, which was 10% substrate conversion from 15 μM NAD+ (approx. Km). 

CD38 Enzyme Titration

Enzyme Titration for CD38 Assay

Linear Response

Linear Response Data with CD38

Screen for Inhibitors & Perform SAR

1280 compounds were screened from the Tocris 2.0 Library set. An interference screen was performed to eliminate compounds interfering with coupling enzyme and/or detection reagents. A total of 5 potential inhibitors were identified with polarization values ≥ 3 standard deviations above the mean. Out of these 5 compounds, one showed no interference with assay detection mixture and was selected for further study. The selected hit from the pilot screen was then tested in dose-response mode. 

CD38 Pilot Screen

CD38 Pilot Screen of 1280 Small Molecules

Inhibitor Dose Response Profiling

Dose Response Curve with CD38 Assay

IC50 = 1.01 µM

Overview of the Transcreener ADPR Assay (Sold Separately)

Transcreener ADPR Assay Schematic Final

The Transcreener ADPR Assay is a biochemical HTS assay for quantitative measurement of ADP-ribose (ADPR) production in enzymatic reactions. The assay uses a coupling enzyme to convert ADPR into AMP, which is then detected using a far-red, competitive fluorescence polarization (FP) assay. 

The assay is designed for high throughput screening (HTS). The sensitivity and selectivity of the assay allows for the ability to obtain robust assay signals (>100 mP) with less than 10 nM of enzyme and a Z' value greater than 0.7. It is available in an easy-to-use, mix-&-read format. 

BellBrook's Recombinant CD38 Enzyme

Active, human Cluster of differentiation 38 enzyme, His-tagged protein expressed & purified. The enzyme is thoroughly validated with the Transcreener ADPR Assay Kit. For specific activity, please refer to the Certificate of Analysis for each individual enzyme lot. Purity is >90% in a 50 mM Tris, 500 mM NaCl, 20% glycerol buffer composition (pH 8.0). Currently used with the Transcreener assay at concentrations between 0.1-1.2 nM.

Graphic CD38 Enzyme

CD38 Assay Services

Interested in moving your program forward with BellBrook's CD38 Assay services? BellBrook scientists will use their extensive biochemistry and enzymology expertise to work with you and accelerate your CD38 discovery program.

Assay Development Services

Lead Discovery Services Include:

  • Inhibitor Screening – To identify or confirm activity with the target.
  • Inhibitor Potency Profiling – Dose-response with target and/or related proteins. Fast IC50 results.
  • Mechanism of Action Studies – Kinetic analysis to define the mode of inhibition.

Contact Us to Learn More

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What's Included

What You Will Need

Enzolution CD38 Assay System

* For custom or bulk orders (over 100,000 wells) please contact us (info@bellbrooklabs.com) for a quote.

Transcreener ADPR Assay Kits

* For custom or bulk orders (over 100,000 wells) please contact us (info@bellbrooklabs.com) for a quote.

Related Resources

Interconnections Between the DNA Damage Response and Innate Immunity

There is extensive crosstalk between the DNA damage response (DDR) pathways and innate immune pathways. Both the individual pathways and the interconnections between them are a focus for exciting new small molecule drug therapeutics that target cancers and debilitating autoimmune disorders. The Transcreener HTS Assay platform accelerates these efforts by providing a robust and easy-to-use biochemical assay to measure activity of key enzymes in the innate immune and DDR pathway.

In this guide, we provide an overview of the DDR and innate immune pathway, and describe Transcreener Assays and Assay Systems for key therapeutic targets. The enzyme targets discussed include:


  • POLQ
  • WRN
  • PARP1
  • PARG
  • DNA PK

Innate Immunity

  • cGAS
  • TREX1
  • TBK1
  • IKKβ
  • IRAK4
  • ENPP1
  • CD38
  • OAS-1
  • RIG-1/MDA5
  • DDX3
  • CD39
  • CD73
DNA Damage Response and Innate Immunity Preview

The Role of CD38 As a Therapeutic Target

CD38 contributes to immune response, cell adhesion, and signal transduction. Furthermore, it plays a vital role in calcium signaling, acting as a second messenger to regulate muscle contraction, cell growth, fertilization, and cellular motility. Because of this role, CD38 is a target for tumor evasion and inflammatory-related diseases.

Calcium levels are increased in patients with multiple myeloma (MM). MM is a type of cancer that affects plasma (white blood) cells, ultimately affecting antibody production. Additionally, asthma can result from calcium levels not being appropriately regulated. Discovering CD38 inhibitors will help combat a plethora of illnesses. Read more in this article from BellBrook Labs.