Learn More About Transcreener Method Used for This NSP13 Assay

Discover NSP13 Modulators with the Transcreener ADP2 NSP13 Assay

The Transcreener ADP² Assay directly measures the ADP produced by NSP13 (also known as nonstructural protein 13 or SARS-CoV-2 NSP13 Helicase). These ADP measurements allow researchers to effectively determine the activity of the NSP13 enzyme. The assay provides a powerful tool to screen compound libraries for NSP13 modulators to help find new therapeutic antivirals for SARS-CoV-2.

The kit comes complete with all the detection reagents required to measure activity. NSP13 enzyme is not included in the inhibitor screening assay kit. Please contact us for questions related to acquiring the enzyme.

The Role of NSP13 As Therapeutic Target

The COVID-19 outbreak has led to intense research to find new therapeutics to help treat the disease. As a result, a variety of different targets are currently being explored to help fight the pandemic. As an antiviral target, NSP13 is critical for SARS-CoV-2 replication, thus making it an area of extreme interest to battle the disease.

As one of the 16 known coronavirus nonstructural proteins, NSP13 is the most similar to other forms of the virus, such as MERS-CoV and SARS-CoV, making it an exciting target not only for the current pandemic but for future outbreaks as well (White et al. 2020). 

Direct Detection of ADP to Measure NSP13 Enzymatic Activity

NSP13 Assay Schematic

The workhorse. Used in many large screens. Best deck and signal stability.

ADP FI Kinase Assay

Positive FI signal. Compatible with simple fluorescence plate readers. Faster read time than FP or TR-FRET.


For customers who prefer TR-FRET detection. Uses the same filter set as HTRF®.


  • Measure Enzymatic Activity of NSP13
  • Screen Compound Libraries for NSP13 Modulators
  • Quantify Inhibitor Potency
  • Inhibitor Selectivity Profiling
  • Measure Drug-Target Residence Time


  • Direct detection of unlabeled ADP
  • Easy to use, homogenous, one-step format
  • Robust Assay Z’ > 0.7 under initial velocity conditions
  • Far-red fluorescent readouts minimize compound interference
  • A safe, non-radioactive method
  • Available in FP, FI, or TR-FRET readouts

Easy-to-Use, Mix-and-Read, HTS-Ready Assay

The Transcreener ADP² NSP13 Assay is in a simple, HTS-ready, mix-and-read format. Run your enzyme reaction, add Transcreener reagents, and read your plates. The assay is compatible with 96, 384, and 1536-well formats.

Detection of ADP Under NSP13 Initial Velocity - FP Readout

The assay demonstrates linearity when raw data is converted to ADP using a standard curve. Here we use 500 µM ATP with 20 µM dsRNA substrate. Linearity is shown here under initial velocity conditions when raw data is converted to ADP formed. The buffer includes 20 mM Tris pH 7.5, 1 mM MgCl2, 2.5 mM NaCl, 0.005% Brij, 0.005% BSA, 225 μg/mL ADP2 antibody, and 2 nM ADP Alexa 633 tracer. The NSP13 enzyme reaction took place for 60 minutes at 37ºC in kinetic mode.

NSP13 Enzyme Titration

Linear Response

Screen for Inhibitors & Perform SAR

Transcreener Assays are designed for screening compound libraries in a high throughput format. Follow-up SAR can also be performed using the assay to determine inhibitor potency with ease. Assay conditions include 125 pM NSP13, 500 µM ATP, and 20 µM dsRNA for 60 minutes at 37ºC in kinetic mode.

Dose-Response - Suramin

NSP13 Assay Suramin Dose Response

IC50 = 0.91 µM

Robust Assay Yields Quality Data

Z’ measurements using optimized NSP13 reaction conditions indicate a robust assay.  Robust data like this is vital for sizeable high throughput screens that are difficult to complete due to massive sample quantity. Both reactions have 0.5 mM ATP, 20 µM dsRNA, and 125 pM NSP13 for an enzyme reaction of 30 minutes at 37°C. Z' shown here = 0.75.

NSP13 Assay Z Prime

NSP13 Assay Services

Interested in moving your program forward, but don't want to bring an assay in-house? Our scientists can help! BellBrook scientists will use their extensive biochemistry and enzymology expertise to work with you and accelerate your NSP13 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.
  • Residence Time Measurements – Determination of koff using ‘jump dilution’ enzymatic assay method.
  • Mechanism of Action Studies – Kinetic analysis to define the mode of inhibition.

Contact Us to Learn More

Please fill out the form below. We will respond quickly to get the conversation moving and learn how we can help. We keep things discrete, confidential, and professional.

Far-Red FP, FI & TR-FRET Readouts Validated on Major Multimode Readers

Supplier Instrument FP Assays
FI Assays
TR-FRET Assays
berthold logo TriStar²S LB 942 in review validated validated
Mithras² LB 943 in review validated validated
bioteklogo Cytation™ 5 validated validated validated
Cytation™ 3 validated validated validated
Cytation™ 1 validated validated validated
Synergy™ H1 validated validated validated
Synergy™ 2/H4/4 validated validated validated
Synergy™ HTX not capable validated not capable
Synergy™ Neo 2 validated validated validated
BMGLABTECH Logo POLARstar® Omega validated validated validated
FLUOstar® Omega not capable validated validated
PHERAstar® FSX validated validated validated
PHERAstar® Plus/FS validated validated validated
CLARIOstar® /Plus validated validated validated
VANTAstar validated validated validated
hidex logo Sense in review validated in review
MDS AT logo Analyst® GT/HT validated validated validated
Gemini® XPS/EM not capable validated not capable
SpectraMax® M2/M2e not capable validated not capable
SpectraMax® M5/M5e/FlexStation® 3 not capable validated validated
SpectraMax® Paradigm validated contact us contact us
SpectraMax® iD3/iD5 in review validated validated
perkinElmerLogo EnVision®/EnVision® Xcite validated validated validated
tecanLogo Infinite® M1000/M1000Pro/Safire2™ validated validated validated
Infinite® M200 not capable validated not capable
Infinite® F500 validated validated validated
Infinite® F200/Ultraevolution contact us validated contact us
Spark™ 10M validated validated validated

What's Included

What You Will Need