ADK Assay Kit - Human Adenosine Kinase Activity Assay

PRECICE® ADK Assay Kit is a convenient, non-radioactive, high-throughput-compatible assay for measuring human adenosine kinase (ADK) activity in vitro. It is designed for drug discovery programs screening for novel ADK inhibitors, and includes ready-to-use human recombinant ADK enzyme.

Assay Principle

Adenosine kinase (ADK) transfers the terminal phosphate group of ATP to a substrate, generating ADP as a by-product. This kit uses inosine as a surrogate ADK substrate, coupled to a highly active IMP dehydrogenase (IMPDH) reaction that directly reports the inosine monophosphate (IMP) formed by ADK. In the presence of inosine and ATP, ADK phosphorylates inosine into IMP; IMPDH then immediately oxidizes IMP to XMP in the presence of NAD, producing NADH2. Because IMPDH is provided in excess, ADK activity is the rate-limiting step, so NADH2 formation — monitored continuously by absorbance at 340 nm — directly and stoichiometrically reflects ADK activity.

Reaction scheme of the PRECICE ADK Assay Kit: ADK phosphorylates inosine to IMP, coupled to IMPDH oxidation of IMP to XMP with NADH2 formation, monitored at 340 nm

PRECICE® ADK Assay Kit

Ref. #K0507-01

PRECICE ADK Assay Kit contents: lyophilized cofactor and enzyme tubes (DTT, NAD, ATP, IMPDH, human ADK enzyme, inosine substrate, A-134974 inhibitor), 5x reaction buffer tube, and 96-well microplate
#REF SIZE PRICE
#K0507-01 PRECICE® Adenosine Kinase Assay Kit
Includes active human Adenosine kinase enzyme		 530.00 €
530.00 €
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Updated on July 30th, 2026.

Kit is provided in stable lyophilized form and shipped without dry ice

Download In vitro ADK assay protocol (User manual, ref. K0507-01)

Key Features of the ADK Assay Kit

Convenient

  • Non-radioactive, add-and-measure format
  • Homogeneous assay, no wash or separation steps
  • Continuous absorbance monitoring at 340 nm

Quantitative

  • IMP converted to NADH₂ in a stoichiometric, quantitative manner
  • Enables accurate kinetic analysis (Km, Vmax, IC50)

High-Throughput Format

  • Standard 96-well microplate format
  • Compatible with plate readers fitted with a 340 nm filter
  • Meets HTS assay standards (Z'-factor 0.68)

Validated & Reliable

  • Validated with reference ADK inhibitor A-134974
  • Confirmed activity on ribavirin, a known ADK substrate
  • Includes human recombinant ADK enzyme (20 nmol)

For rapid in vitro screening of nucleoside analog phosphorylation by human adenosine kinase, see our PRECICE® ADK Phosphorylation Assay Kit

Why Adenosine Kinase Is a Drug Discovery Target

Adenosine kinase (ADK) is a ubiquitous enzyme that regulates intra- and extracellular concentrations of adenosine, an important modulator of central nervous system function and a signaling molecule involved in hypoxia, inflammation, and nociception. Together with adenosine deaminase, ADK controls cellular adenosine levels. Inhibiting ADK selectively raises local adenosine concentrations, which has been shown to reduce seizure susceptibility and nociception in vivo. ADK dysfunction is implicated in several pathologies, including diabetes, epilepsy, and cancer, making it a rational therapeutic target. Adenosine-regulating drugs have been investigated as analgesic and anti-inflammatory agents, and for the treatment of schizophrenia and ischemic brain injury.

Kit Contents

Each PRECICE® ADK Assay Kit (one 96-well plate, 96 assays) includes:

  • Cofactor 1 (DTT, lyophilized)
  • Cofactor 2 (NAD, lyophilized)
  • Cofactor 3 (ATP, lyophilized)
  • Highly active IMPDH (lyophilized)
  • Human recombinant ADK enzyme (lyophilized, 20 nmol)
  • Inosine substrate solution (50 mM)
  • ADK inhibitor reference compound, A-134974 (50 µM solution)
  • Reaction Buffer 5x (4 mL, in a 50 mL tube)
  • Round-bottom 96-well microplate (Corning® Costar®, ref. 3797)

Full step-by-step preparation and plate-layout instructions are provided in the user manual.

Validation Data

PRECICE® ADK Assay Kit was validated for ADK inhibitor screening and IC50 determination using the reference compound A-134974 (Sigma-Aldrich, under license from Abbott Laboratories). The Z'-factor was calculated from 44 negative (no ADK inhibition) and 44 positive (500 nM A-134974) control wells and measured at 0.68 — an excellent level of performance for a screening assay.

Dose-response inhibition curve of human adenosine kinase by A-134974, showing IC50 determination across 12 concentrations
ADK inhibition curve with compound A-134974 at 12 different concentrations.
All data points represent the mean (± SD) of 8 wells (2 wells in duplicate, on 4 independent plates). IC50 was determined by fitting a 4-parameter non-linear curve to the data using the least-squares method. IMPDH activity assays confirmed that IMPDH itself is not inhibited by A-134974 (data not shown).

Frequently Asked Questions

The enzymatic activity of human adenosine kinase in vitro. ADK phosphorylates inosine to IMP, which is immediately oxidized by a coupled IMPDH reaction to produce NADH2, monitored continuously by absorbance at 340 nm.

Yes. The kit is validated for high-throughput screening (HTS) of ADK inhibitors and IC50 determination, with a Z'-factor of 0.68. It was benchmarked using the reference inhibitor A-134974.

No. It is a non-radioactive, homogeneous, add-and-measure assay based on continuous spectrophotometric monitoring, with no separation or wash steps required.

A plate agitator and a microplate reader fitted with a 340 nm absorbance filter (for example, Labsystems iEMS Reader MF, BioTek Epoch, or PerkinElmer readers).

Reagents are provided in stable lyophilized form and shipped without dry ice. Store at -20°C upon receipt.

One 96-well plate kit (96 assays) contains lyophilized cofactors (DTT, NAD, ATP), lyophilized highly active IMPDH, lyophilized human recombinant ADK enzyme (20 nmol), an inosine substrate solution, an A-134974 ADK inhibitor reference solution, 5x reaction buffer, and a round-bottom 96-well microplate.
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Scientific Works citing NOVOCIB Adenosine Kinase and PRECICE® ADK Assay kits

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  1. M. Orlicka-Płocka, A. Fedoruk-Wyszomirska, D. Gurda-Wozna, P. Pawelczak , P. Krawczyk, M. Giel-Pietraszuk, G. Framski, T. Ostrowski, E. Wyszko. Implications of Oxidative Stress in Glioblastoma Multiforme Following Treatment with Purine Derivatives. Antioxidants 2021, 10, 950.
  2. L.M. Johnson, O.J. Smith, D.A. Hahn, C.F. Baer. Short-term heritable variation overwhelms 200 generations of mutational variance for metabolic traits in Caenorhabditis elegans. Evolution. 2020 Nov;74(11):2451-2464.
  3. S. Asada, E. Ohta, Y. Akimoto, N. Abolhassani, D. Tsuchimoto, Y. Nakabeppu. 2‑Oxoadenosine induces cytotoxicity through intracellular accumulation of 2‑oxo‑ATP and depletion of ATP but not via the p38 MAPK pathway. Scientific Reports. 2017;7:6528.
  4. U. Nayar, J. Sadek, J. Reichel, D. Hernandez-Hopkins, G. Akar, P.J. Barelli, M.A. Sahai, H. Zhou, J. Totonchy, D. Jayabalan, R. Niesvizky, I. Guasparri, D. Hassane, Y. Liu, S. Sei, R.H. Shoemaker, J. D. Warren, O. Elemento, K.M. Kaye, E. Cesarman. Identification of a nucleoside analog active against adenosine kinase-expressing plasma cell malignancies. J Clin Invest. 2017 Jun 1;127(6):2066-2080.
  5. K.S. Toti, D. Osborne, A. Ciancetta, D. Boison, K.A. Jacobson. South (S)- and North (N)-Methanocarba-7-Deazaadenosine Analogues as Inhibitors of Human Adenosine Kinase. J. Med. Chem. 2016, 59, 14, 6860-6877.
  6. K. DANIELYAN, R. D. VARDANYAN, A. SIMONYAN, A. S. SAGYAN. The sole role of PRPS-1 in the regenerative processes after experimental stroke. Poster#: 459.07/A7. 2017 Neuroscience Meeting Planner.
    Washington, DC: Society for Neuroscience, 2017.
  7. M.K. Bjursell, H.J. Blom, J.A. Cayuela, M.L. Engvall, N. Lesko, S. Balasubramaniam, G. Brandberg, M. Halldin, M. Falkenberg, C. Jakobs, D. Smith, E. Struys, U. von Döbeln, C. M. Gustafsson, J. Lundeberg, A. Wedell. Adenosine Kinase Deficiency Disrupts the Methionine Cycle and Causes Hypermethioninemia, Encephalopathy, and Abnormal Liver Function. Am J Hum Genet. 2011 Oct 7; 89(4): 507-515.
  8. E. CESARMAN, U. NAYAR, J.D. WARREN, J. SADEK. US20190225643A1 Novel nucleoside analogs and use thereof in therapeutic treatment. Patent application filed by Cornell University.