PRECICE® HPRT Assay Kit

Spectrophotometric microplate assay for precise measurement of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity in research and clinical diagnostics

Includes active human HPRT enzyme Non-radioactive method 96-well microplate format

Developed by our R&D team, the PRECICE® HPRT Assay Kit represents a breakthrough in HPRT enzyme analysis. As the first non-radioactive solution for measuring HPRT activity, this innovative kit was specifically designed for user-friendly application in a 96-well plate format, eliminating the need for hazardous radioactive materials while maintaining exceptional sensitivity and accuracy. ResarchGate

HPRT (EC 2.4.2.8) is a pivotal enzyme in the purine salvage pathway, encoded by the highly polymorphic HPRT1 gene. Over 300 pathogenic variants have been documented, with mutations linked to partial or complete enzymatic deficiency. Complete HPRT deficiency results in Lesch-Nyhan syndrome, a rare X-linked genetic disorder. In other cases, HPRT deficiency may contribute to secondary forms of gout—one of the most prevalent purine metabolism disorders (Ceballos-Picot I. et al., 2010). Due to the extensive variability of the HPRT1 gene, genetic diagnosis can be challenging. Traditional functional assays rely on red blood cell lysates and chromatographic detection with radiolabeled ¹⁴C-hypoxanthine (Cartier P. et al., 1968).

Assay Principle:
HPRT activity is determined by measuring the enzymatic conversion of hypoxanthine to inosine monophosphate (IMP). IMP is then oxidized to xanthosine monophosphate (XMP) by recombinant IMP dehydrogenase (IMPDH), reducing NAD⁺ to NADH in the process. The accumulation of NADH is continuously monitored by absorbance at 340 nm, enabling real-time kinetic analysis of HPRT activity.

HPRT Assay Kit Composition
HPRT enzyme Molecular Structure

PRECICE® HPRT Assay Kit

#K0709-01-2
#REF SIZE PRICE
#K0709-01-2 PRECICE® HPRT Assay Kit
10 mL, 24 analyses (8 samples in triplicate)		 420.00 €
420.00 €
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Updated on October 9th, 2025.

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

Download HPRT assay Protocol (User manual)

Download Application Notes

Download Material Safety Data Sheet (MSDS)

🔎 Wide Detection Range

Detect HPRT activity from 6.75 to 340 nmol/hour/ml, capturing both complete and partial deficiencies.

🎯 Accurate

Low variability: 1.5% (within-run), 5% (between-day), and 6.5% (total imprecision).

⚡ Fast

Analyze up to 15 samples in triplicate in just 2 hours.

🧪 Convenient

Skip sample prep: use untreated cell lysates without inactivating 5'-nucleotidase.

✅ Validated

Results consistent with radiochemical protocols across erythrocytes, PBMCs, and cultured cells.

📦 Ready-to-Use

Supplied in a stable lyophilized form and shipped without dry ice—easy to store and prepare on demand.

HPRT Enzyme Activity Measurements

Cell Type PRECICE® HPRT Assay Kit
(nmol/h/mg or per 10⁶ cells)		 Published Data
(nmol/h/mg or per 10⁶ cells)		 Ref*
RBC specimen 1 (n=4) 76.94 ± 2.5 80-120 (per mg Hgb) 4
RBC specimen 2 (n=12) 78.03 ± 5.52
RBC specimen 3 (n=4) 88.7 ± 3.41
PBMC specimen 1 (n=4) 159.91 ± 3.60 (per mg protein)
19.7 ± 0.6 (per 10⁶ PBMC) 		343 ± 18 (per mg protein)
10.2-18.0 (per 10⁶ PBMC) 		4
PBMC specimen 2 (n=4) 152.30 ± 4.94 (per mg protein)
21.3 ± 0.42 (per 10⁶ PBMC) 		5
Human Dermal Fibroblasts (Invitrogen) 70.91 ± 2.67 81-127 (per mg protein) 6
W20-17 cells (ATCC) 91.95 ± 4.49
HPRT Assay Kit Calibration Graph
Calibration curve of IMPDH-based PRECICE® HPRT Assay

The rate of the increase in absorbance at 340nm per hour as a function of the concentration of human recombinant HPRT enzyme (NovoCIB, ref. E-Nov-9). The changes in absorbance corresponding to 3 different control hemolysates diluted in complete reaction mixture to final hemoglobin concentration 1mg/ml (n=4) are shown by filled squares, filled triangles and filled circles. The insert shows a linear correlation observed in whole range of 21ng/ml up to 1.5µg/ml of recombinant HPRT; the units are the same.

🔬 Advantages of IMP-Dehydrogenase in the HPRT Assay

🎯 Targeted Specificity

IMPDH is highly selective for IMP, ensuring accurate downstream detection.

💊 Drug-Compatible

Allopurinol-insensitive—ideal for analyzing patient samples under treatment.

🔁 Reaction Directionality

Ensures irreversible forward flow from IMP to XMP, avoiding reverse HPRT activity.

🧪 Nucleotidase-Resistant

Excess IMPDH outcompetes endogenous 5'-nucleotidase, preserving assay accuracy.

📈 Real-Time Monitoring

Direct NADH readout at 340 nm enables continuous kinetic measurements.

💡 Research & Clinical Applications

  • 🧬 Enzyme deficiency diagnosis — e.g., Lesch-Nyhan syndrome
  • 🧬 HPRT mutation screening for functional studies and diagnostics
  • 🧬 Drug screening targeting HPRTs of protozoan parasites (e.g., Plasmodium, Leishmania)
  • 🧬 Toxicology assays using HPRT as a genotoxicity biomarker

Scientific Research & Publications

The PRECICE® HPRT Assay Kit has been cited in numerous peer-reviewed publications, demonstrating its reliability and effectiveness in HPRT research:

  1. CRISPR/Cas9-mediated generation of human embryonic stem cell sub-lines with HPRT1 gene knockout to model Lesch Nyhan disease
  2. The Applicable Use of the HPRT Gene Mutation Assay as a Practical Tool in Mutagenesis and DNA Repair Studies
  3. Ablation of Atp5if1 impairs metabolic reprogramming and proliferation of T lymphocytes and compromises mouse survival
    I. Romero-Carraminana, S. Dominguez-Zorita, P.B. Esparza-Molto, J. M. Cuezva (2024) iScience 27, 109863
  4. Electron transport chain inhibition increases cellular dependence on purine transport and salvage
    Z. Wu, D. Bezwada, F. Cai, J. Garcia-Bermudez, M. Ni, R.J. DeBerardinis, Cell Metab. 2024 Jun 7:S1550-4131(24)00190-6
  5. Therapeutic gene correction for Lesch-Nyhan syndrome using CRISPR-mediated base and prime editing (2023)
    G. Jang , H. Rim Shin, H.-S. Do , J. Kweon , S. Hwang , S. Kim, S. Hee Heo, Y. Kim, B. Lee Molecular Therapy - Nucleic Acids ; 31: 586-595.
  6. Rescuing compounds for Lesch-Nyhan disease identified using stem cell-based phenotypic screening (2020)
    V. Ruillier, J. Tournois, C. Boissart, M. Lasbareilles, G. Mahé, L. Chatrousse, M. Cailleret, M. Peschanski, A. Benchoua JCI Insight 5(4): e132094.
  7. Hypoxanthine-guanine phosphoribosyltransferase and inosine 5'-monophosphate dehydrogenase activities in three mammalian species: aquatic (Mirounga angustirostris), semi-aquatic (Lontra longicaudis annectens) and terrestrial (2015)
    M. Barjau Pérez-Milicua, T. Zenteno-Savín, D.E. Crocker, J.P. Gallo-Reynoso Front Physiol.; 6: 212.
  8. Prolonged fasting increases purine recycling in post-weaned northern elephant seals
    José Guadalupe Soñanez-Organis, José Pablo Vázquez-Medina, Tania Zenteno-Savín, Andres Aguilar, Daniel E. Crocker, Rudy M. Ortiz J Exp Biol (2012) 215 (9): 1448-1455.
  9. IF1 ablation prevents ATP synthase oligomerization, enhances mitochondrial ATP turnover and promotes an adenosine-mediated pro-inflammatory phenotype (2023)
    Joe Carroll, Ian N. Watt, Charlotte J. Wright, Shujing Ding, Ian M. Fearnley, John E. Walker Cell Death Dis. 14(7):413.
  10. Purine metabolism in response to hypoxic conditions associated with breath-hold diving and exercise in erythrocytes and plasma from bottlenose dolphins (Tursiops truncatus) (2016)
    Iris del Castillo Velasco-Martínez, Claudia J. Hernández-Camacho, Lía C. Méndez-Rodríguez, Tania Zenteno-Savín Comp Biochem Physiol A Mol Integr Physiol 191:196–201.
  11. Comparison of human erythrocyte purine nucleotide metabolism and blood purine and pyrimidine degradation product concentrations before and after acute exercise in trained and sedentary subjects (2018)
    Wioleta Dudzinska, M. Suska, A. Lubkowska, K. Jakubowska, M. Olszewska, K. Safranow, D. Chlubek J Physiol Sci 68(3):293–305.
  12. NUDT5 regulates purine metabolism and thiopurine sensitivity by interacting with PPAT (2025)
    Zheng Wu, Phong T Nguyen, Varun Sondhi, Run-Wen Yao, Tao Dai, Jui-Chung Chiang, Zengfu Shang, Feng Cai, Ling Cai, Jing Zhang, et al. bioRxiv.