Learn More About Transcreener Method Used for This OAS1 Assay

Discover OAS1 Modulators with Transcreener OAS1 Assay Services

The Transcreener OAS1 Assay measures the 2-5A produced by OAS1 (also known as 2'-5'-oligoadenylate synthetase 1). By measuring the production of OAS1 researchers can effectively determine the activity of the OAS1 enzyme. The assay provides a powerful tool to screen compound libraries for OAS1 modulators to help find new therapeutics for a variety of different conditions including autoimmune diseases.

The assay is currently available as a service performed in-house at BellBrook Labs. Please contact us for questions related to acquiring the assay.

The Role of OAS1 In Innate Immunity

Double stranded RNA enters the cell from viral infection. As a first line of defense in the innate immune system, OAS1 is activated by viral double-stranded RNA. Upon activation, OAS1 synthesizes 2-5A from ATP which in turn activates RNase L. The result of this signaling event cleaves both viral and host RNA and in turn inhibition of protein synthesis in the cell, thus ending the replication of invading RNA viruses. Mutation or inadvertent stimulation can produce autoimmune conditions by activating the pathway inconsistently even while not in the presence of viral invaders.

Detection of 2-5A to Measure OAS1 Enzymatic Activity

Transcreener OAS1 Assay Schematic

In the presence of dsRNA OAS1 uses ATP to produce the messenger 2-5A. The assay uses a coupling enzyme which generates AMP from the 2-5A. The AMP is then measured by the proven Transcreener AMP/GMP Assay with an FP readout.


  • Measure Enzymatic Activity of OAS1
  • Screen Compound Libraries for OAS1 Modulators
  • Quantify Inhibitor Potency
  • Inhibitor Selectivity Profiling


  • Designed as in homogenous, one-step format to enable reproducability.
  • Robust Assay Z’ > 0.7 under initial velocity conditions
  • Far-red fluorescent readouts minimize compound interference
  • Available in FP, FI, or TR-FRET readouts depending on your requirements

Mix-and-Read, HTS-Ready Assay, for Robust Screening

The Transcreener OAS1 Assay is in a, HTS-ready, mix-and-read format. We'll run your enzyme reaction, add Transcreener reagents, and read the plates. The assay is compatible with 96, 384, and 1536-well formats.

Enzyme Titration with the Transcreener OAS1 Assay - FP Readout

The assay demonstrates linearity when raw data is converted to the product formed using a standard curve. Linearity is shown under initial velocity conditions when raw data is converted to AMP formed as 2-5A is broken down by the detection reagents.

Human OAS1 Enzyme Titration

OAS1 Assay Enzyme Titration Raw Data

Data Converted to Product Formed

OAS1 Assay Enzyme Titration Converted Data

OAS1 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 OAS1 or innate immunity 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

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