Human IMPDH, Type II (IMPDH2)

Synonyms: inosine 5'-monophosphate dehydrogenase, type 2, IMP dehydrogenase, type II, IMPDH2.

Inosine 5'-monophosphate dehydrogenase type 2 (IMPDH 2, E.C.1.1.1.205) is the predominant isoform of IMPDH and a validated target to treat a wide range of cancers and infectious diseases and to prevent lymphocytes proliferation.

Catalytic activity
Inosine Monophosphate Dehydrogenase (IMPDH) converts inosine 5'-monophosphate (IMP) to xanthosine 5µ-monophosphate (XMP) using NAD+ as a cofactor.

The oxidation of IMP to XMP is considered as the pivotal step in the biosynthesis of guanine nucleotide, whose pool controls cell proliferation and many other major cellular processes(1). The decrease in guanine nucleotide resulting from IMPDH inhibition interrupts the nucleic acid synthesis in proliferating cells. The involvement of IMPDH in de novo guanine nucleotide biosynthesis makes IMPDH a crucial enzyme in cell proliferation and differentiation(2). IMPDH is recognized as a validated target for several major therapeutic areas. IMPDH inhibitors are exploited as antiviral (e.g. ribavirine), antiparasitic, antimicrobial, antileukemic, and immunosuppressive agents(2). IMPDH Type II is the predominant isoform of the enzyme and is selectively expressed in proliferating cells, including lymphocytes and tumor cells(2).

NOVOCIB's IMPDH 2 has been cloned by RT-PCR amplification of mRNA extracted from human hepatoma cells (NP_000875.2, 100% identity) and expressed in E.coli.

NOVOCIB's purified IMPDH 2 is an active enzyme characterized for its affinity for inosine 5'-monophosphate and NAD substrates, and its sensitivity to enzyme inhibitors such as mycophenolic acid and ribavirine-monophosphate.

Unit Definition: One unit of IMPDH Type II catalyzes the oxydation of 1 µmole of IMP to XMP per minute at pH 8.8 at 37 µC.

High Specific Activity: > 200 mU/mg protein.

Human IMPDH Type 2 enzymatic reaction: IMP + NAD+ → XMP + NADH + H+

Human IMPDH Type 2

Ref. #E-Nov1
#REF SIZE PRICE
#E-Nov1-100 Human IMPDH Type 2
100mU		 295.00 €
295.00 €
Inquiry
#E-Nov1-250 Human IMPDH Type 2
250mU		 550.00 €
550.00 €
Inquiry

Last updated on : October 8th, 2025.

Product Code: E-Nov1

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

You can ask us for a quotation here or write at contact@novocib.com

Download our brochure "NovoCIB's IMPDH Products & Services"

Assay condition: KH2PO4 0.1M, pH8.8, NAD 250µM, DTT 2.5mM, 2.5mU/ml of human recombinant IMPDH II, Incubation at 37µC. Reaction started by adding IMP at 250µM final concentration. NADH formation was followed in an iEMS Reader MF (Labsystems) plate reader at 340nm.

SDS-PAGE analysis of purified Human IMPDH Type 2 showing high purity
Dose-response curve showing IMPDH Type 2 inhibition by mycophenolic acid

Download this Document: "NOVOCIB's Human Recombinant IMPDH"

Download this Document: "NOVOCIB - IMPDH Products & Services"

How to measure the activity of IMPDH 2

  1. Resuspend the content of the tube with lyophilized IMPDH type 2 (50–100 mU) in 200 µL of deionized water.
  2. Prepare fresh reaction buffer: 1 mL of 50 mM KH₂PO₄ pH 8.5, 5 mM DTT*, 1 mM IMP*, 36°C.
  3. Add 20 µL of IMPDH (or 10 µL for 100 µL) per 1 mL of buffer without NAD*.
  4. Add 200 µL of this mixture to 4 wells and preincubate at 36°C for 10 min.
  5. To start the reaction, add 5 µL of 40 mM NAD (1 mM final concentration) to 2 wells, leaving 2 others as a blank.
  6. Follow the reaction at 340 nm and 25–36°C.

*For best results, always use freshly prepared solutions of DTT, IMP, and NAD.

Absorbance at 340 nm (200 µL per well, Corning® 3797 microplate)
Time (min) IMP 1 mM, no NAD IMP 1 mM, no NAD (duplicate) IMP 1 mM + 1 mM NAD IMP 1 mM + 1 mM NAD (duplicate)
0 0.118 0.116 0.167 0.165
1 0.118 0.116 0.205 0.203
2 0.119 0.117 0.244 0.240
3 0.120 0.116 0.283 0.278
4 0.121 0.116 0.322 0.316
5 0.121 0.116 0.362 0.354
6 0.121 0.116 0.401 0.392
7 0.122 0.116 0.440 0.430
Calculated Slopes (AU/min)
  • IMP 1 mM, no NAD: 0.0006
  • IMP 1 mM, no NAD (duplicate): 0
  • IMP 1 mM + 1 mM NAD: 0.0391
  • IMP 1 mM + 1 mM NAD (duplicate): 0.0378
Slope Mean (AU/min)
  • IMP 1 mM, no NAD: 0.0003
  • IMP 1 mM + 1 mM NAD: 0.0385
Slope After Blank Subtraction

AU/min: 0.0382

Enzyme Activity Calculations
  • Activity in well (U/mL): 0.00796
    (divide AU/min by 4.8 which corresponds to absorbance of 1mM NADH in 200µL well of Corning® 3797 microplate)
  • Dilution factor (20 µL per 1 mL): ×50
  • Activity of enzyme solution (U/mL): 0.398
  • Amount of enzyme per tube (Units): 0.080
Kinetics of NADH Formation

IMPDH - A Key Target for Therapeutic Applications

Key Features:

  • High-purity human recombinant IMPDH Type 2
  • Fully characterized enzyme activity
  • Validated for inhibitor screening
  • Suitable for cancer and immunology research
  1. Identify IMPDH2 inhibitors using NOVOCIB’s IMPDH type 2 or PRECISE IMPDH2 assay kit.
  2. Compare against known inhibitors like MPA or ribavirin.
  3. Confirm GTP depletion in inhibitor-treated cells using NOVOCIB’s Cellular Nucleotide Profiling (HPLC-UV).
Cell icon Cellular Nucleotides Analysis

To validate IMPDH2 inhibitors identified in vitro, try our analytical service that measures guanine nucleotide depletion and related metabolic changes. These assays confirm whether compounds active in biochemical screens also suppress nucleotide synthesis in living cells.

  • Quantifies >30 ribo- and deoxyribonucleotides (mono-, di-, triphosphates) in a single run.
  • Used to measure depletion of GTP pools in cells treated with IMPDH inhibitors.
  • Validated reference inhibitors include mycophenolic acid (MPA), hydroxyurea (HU), methotrexate (MTX), and ribavirin.

Therapeutic Applications of IMPDH2

IMPDH in Immunology and Autoimmune Diseases

IMPDH plays a critical role in lymphocyte proliferation and immune response modulation, making it a prime target for:

  • Immunosuppressive Therapies: CellCept® (mycophenolate mofetil), a prodrug of mycophenolic acid, is a well-established IMPDH inhibitor used in organ transplantation and autoimmune conditions.
  • Autoimmune Disease Management: IMPDH inhibitors show significant promise in treating various autoimmune disorders including:
    • • Systemic Lupus Erythematosus (SLE)
    • • Rheumatoid Arthritis (RA)
    • • Psoriasis
    • • Myasthenia Gravis
    • • Lupus Nephritis

IMPDH in Oncology and Cancer Research

IMPDH Type 2 is overexpressed in many cancer cells, making it an attractive target for anticancer therapies:

Key Cancer Targets

  • Acute Myelogenous Leukemia (AML)
  • Chronic Myelogenous Leukemia (CML)
  • Pancreatic cancer
  • Colorectal cancer
  • Bladder cancer

Therapeutic Advantages

  • Overcomes drug resistance in cancer cells
  • Enhances efficacy of other anticancer drugs
  • Targets rapidly dividing cancer cells

Current IMPDH Inhibitors in Development

Approved Drugs

  • CellCept® (mycophenolate mofetil)
  • Ribavirin (antiviral)
  • Mizoribine (immunosuppressant)
  • Tiazofurine (antineoplastic)

Promising Candidates

  • AVN-944 - In trials for hematologic malignancies and solid tumors
  • Benzamide riboside - Phase II/III for leukemia
  • Novel small molecules - Multiple candidates in preclinical development

The continued elucidation of IMPDH's atomic structure and mechanism of action continues to drive the development of more potent and selective inhibitors, opening new possibilities for targeted therapies across multiple disease areas.

AVN-944
AVN-944 Structure
VX-148
VX-148 Structure
VX-497
VX-497 Structure
MPA (mycophenolic acid)
MPA Structure
CellCept®
MMF Structure
BMS-337197
BMS-337197 Structure
Tiazofurin
Tiazofurin Structure
CellCept®
Ribavirine Structure
Mizoribine
Mizoribine Structure
Scientific References citing Novocib's IMPDH2
book logo
  1. S. Puri, Shalini, K. Juvale, S. Kirubakaran
    Design and Development of New Benzopyrazole Derivatives as Selective Inhibitors of Helicobacter pylori IMPDH Asian Journal of Organic Chemistry. 2025, e00584.
  2. Ayoub N, Upadhyay A, Tête A, Pietrancosta N, Munier-Lehmann H, O'Sullivan TP.
    Synthesis, evaluation and mechanistic insights of novel IMPDH inhibitors targeting ESKAPEE bacteria. Eur J Med Chem. 2024 Dec 15;280:116920. doi: 10.1016/j.ejmech.2024.116920. Epub 2024 Sep 27. PMID: 39369481.
  3. Shah CP, Kharkar PS.
    Newer human inosine 5'-monophosphate dehydrogenase 2 (hIMPDH2) inhibitors as potential anticancer agents. J Enzyme Inhib Med Chem. 2018 Dec;33(1):972-977. doi: 10.1080/14756366.2018.1474211. PMID: 29792360; PMCID: PMC6009919.
  4. Johnvesly Basappa, Shengchun Wang, Cosimo Lobello, David Rushmore, Olga Melnikov, Neil Sen, Vinay Mallikarjuna, Priyanka Jain, Pin Lu, Y. Lynn Wang, Kathy Cai, Reza Nejati, Aaron Goldman, Mariusz Wasik
    Inosine Monophosphate Dehydrogenase-2 (IMPDH2) As the Potential Novel Therapeutic Target in Mantle Cell Lymphoma (MCL): The Underlying Tyrosine Phosphorylation-Based Activation Mechanism and Translational Implications. Blood 2024; 144 (Supplement 1): 1602
  5. Chetan P. Shah, Prashant S. Kharkar
    Discovery of novel human inosine 5'-monophosphate dehydrogenase 2 (hIMPDH2) inhibitors as potential anticancer agents, European Journal of Medicinal Chemistry, Volume 158, 2018, Pages 286-301
  6. Matyugina ES, Andreevskaya SN, Smirnova TG, Khandazhinskaya AL.
    Carbocyclic analogues of inosine-5'-monophosphate: synthesis and biological activity. Acta Naturae. 2012 Oct;4(4):73-7. PMID: 23346382; PMCID: PMC3549521.