GO:0016651 oxidoreductase activity, acting on NAD(P)H: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016651 describes catalysis of redox reactions in which NADH or NADPH serves as the hydrogen/electron donor and reduces a hydrogen or electron acceptor.
• The term covers a large enzyme family including NQO1, PYROXD1, and NAD(P)H-utilizing glutamate dehydrogenases, all sharing NAD(P)H-dependent hydride transfer chemistry [2,6,8].
• NQO1 is the best-characterized human member and is transcriptionally controlled by NRF2 via the antioxidant response element, linking GO:0016651 to cytoprotection and carcinogenesis [4,7].
• Dysregulated NAD(P)H-dependent oxidoreductase activity contributes to cancer, fibromyalgia-associated oxidative stress, and systemic redox imbalance in non-communicable diseases [1,3,5,7].
• PYROXD1 uses NAD(P)+ as an antioxidant to protect tRNA ligase activity during pre-tRNA splicing and the unfolded protein response, expanding the biological roles of this activity beyond detoxification.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect the causal contribution of individual NAD(P)H oxidoreductases to disease phenotypes.
Description
GO:0016651, oxidoreductase activity, acting on NAD(P)H, is a molecular function term in the Gene Ontology that captures a central class of redox enzymes. These enzymes catalyze oxidation-reduction reactions in which NADH or NADPH acts as the hydrogen or electron donor and reduces a hydrogen or electron acceptor. This activity is fundamental to cellular redox homeostasis, xenobiotic detoxification, and biosynthetic pathways, and it is represented across prokaryotes and eukaryotes, from Bacteroides thetaiotaomicron glutamate dehydrogenases to human NQO1 [2,8]. Researchers study GO:0016651 because its members sit at the interface of oxidative stress, metabolism, and disease. For example, NQO1, a prototypical NAD(P)H:quinone oxidoreductase, protects cells against carcinogenesis and is regulated by the NRF2 basic-region leucine zipper and the aryl hydrocarbon receptor basic helix-loop-helix transcription factors. In parallel, altered NRF2 signalling and NAD(P)H-dependent redox imbalance are increasingly recognized in non-communicable diseases and in conditions such as fibromyalgia [1,7]. Understanding GO:0016651 therefore requires integrating enzymology, transcriptional regulation, and disease context. This article summarizes the definition, mechanism, key genes, disease links, and experimental strategies for studying this GO term, with all statements grounded in the verified literature.
oxidoreductase activity, acting on NAD(P)H At A Glance
| GO ID | GO:0016651 |
|---|---|
| GO term | oxidoreductase activity, acting on NAD(P)H |
| Ontology | molecular_function |
| Synonym | NAD(P)H dehydrogenase; oxidoreductase activity, acting on NADH or NADPH; oxidoreductase activity, acting on NADH or NADPH, other acceptor |
| Major function | Catalysis of redox reactions using NADH or NADPH as the hydrogen/electron donor |
| Representative human enzyme | NQO1 (NAD(P)H:quinone oxidoreductase 1) [2,4] |
| Representative non-human enzyme | NAD(P)H-utilizing glutamate dehydrogenase of Bacteroides thetaiotaomicron |
| Key transcriptional regulator | NRF2 via the antioxidant response element [4,7] |
| Disease relevance | Cancer, oxidative stress, fibromyalgia, systemic redox imbalance [1,3,5,7] |
What Is GO:0016651?
GO:0016651 is defined as catalysis of an oxidation-reduction (redox) reaction in which NADH or NADPH acts as a hydrogen or electron donor and reduces a hydrogen or electron acceptor. In practice, this means the enzyme binds a reduced nicotinamide cofactor, transfers hydride (or electrons) from NAD(P)H to a substrate or prosthetic group, and thereby regenerates NAD(P)+. The term is a molecular_function node and includes synonyms such as NAD(P)H dehydrogenase and oxidoreductase activity, acting on NADH or NADPH, other acceptor.
Why Is oxidoreductase activity, acting on NAD(P)H Important in Cell Biology?
GO:0016651 is important because NAD(P)H-dependent oxidoreductases are central to cellular defense against oxidative stress, to the metabolism of quinones and other xenobiotics, and to redox-dependent signaling. The best-studied human example, NQO1, contributes to protection against carcinogenesis and is transcriptionally regulated by NRF2 and the aryl hydrocarbon receptor, making this activity a key node in chemoprevention and cancer biology. Beyond detoxification, NAD(P)H-dependent oxidoreductases such as PYROXD1 sustain essential biosynthetic and quality-control processes, including tRNA ligase activity in pre-tRNA splicing and the unfolded protein response. Because dysregulated redox balance is implicated in cancer, fibromyalgia, and non-communicable diseases, measuring and manipulating GO:0016651 activity is directly relevant to translational research [1,3,5,7].
• Provides the reductive power for detoxification of quinones and other electrophiles through enzymes such as NQO1 [2,4].
• Supports antioxidant defense and redox homeostasis, with NRF2/NQO1 signaling being a therapeutic target in fibromyalgia.
• Contributes to protection against carcinogenesis, as shown for NQO1 in genetic and transcriptional studies.
• Enables selective targeting of NRF2-high pancreatic ductal adenocarcinoma using NQO1-activatable prodrugs.
• Maintains tRNA ligase activity and the unfolded protein response through PYROXD1, linking redox chemistry to RNA processing.
• Is altered in systemic redox imbalance associated with non-communicable diseases.
• Is conserved across bacteria and humans, as illustrated by NAD(P)H-utilizing glutamate dehydrogenases.
• Represents a druggable and genetically tractable node for cancer and metabolic disease research [3,5].
• Serves as a biomarker context for NRF2 pathway activation in tumors [5,7].
• Provides a mechanistic entry point for studying lipid peroxidation and ferroptosis-related cancer therapy.
What Happens During oxidoreductase activity, acting on NAD(P)H?
NAD(P)H binding and cofactor selection
In simple terms: The enzyme first grabs its helper molecule, NADH or NADPH.
The reaction begins when the enzyme binds a reduced nicotinamide cofactor, NADH or NADPH. This binding positions the nicotinamide ring for hydride transfer and determines whether the enzyme functions in catabolic (NADH-linked) or biosynthetic/antioxidant (NADPH-linked) contexts [2,6]. In PYROXD1, NAD(P)+ is used as an antioxidant to sustain tRNA ligase activity, illustrating that the same cofactor-binding scaffold can serve protective rather than purely reductive roles.
Hydride transfer to the acceptor
In simple terms: The enzyme hands off a hydride particle to the target molecule.
Once bound, the enzyme transfers hydride from NAD(P)H to a hydrogen or electron acceptor, which may be a quinone, a disulfide, or another substrate. This step defines the catalytic core of GO:0016651 and regenerates NAD(P)+. For NQO1, the acceptor is typically a quinone, and the two-electron reduction avoids formation of unstable semiquinone radicals, a property relevant to protection against carcinogenesis [2,4].
Product release and redox cycling
In simple terms: The enzyme lets go of the products and is ready to work again.
After reduction, the enzyme releases the reduced acceptor and NAD(P)+, allowing catalytic turnover. In cells, this activity feeds into broader redox networks, including NRF2-driven antioxidant responses, where NQO1 expression is induced through the antioxidant response element [4,7]. Dysregulation of this cycle can contribute to oxidative stress and disease, as seen in fibromyalgia and non-communicable diseases [1,7].
Integration with cellular stress responses
In simple terms: The reaction is plugged into the cell's emergency response system.
NAD(P)H-dependent oxidoreductase activity is integrated with stress-response pathways. PYROXD1 uses NAD(P)+ to protect tRNA ligase activity during pre-tRNA splicing and the unfolded protein response, connecting redox chemistry to RNA processing and proteostasis. In cancer, NQO1 activity can be exploited for prodrug activation in NRF2-high pancreatic ductal adenocarcinoma, showing that this activity is not only protective but also therapeutically actionable.
Key Genes Involved in GO:0016651 oxidoreductase activity, acting on NAD(P)H
The following genes and proteins represent the major experimentally characterized members and regulators of GO:0016651 activity in human and model systems.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NQO1 | NAD(P)H:quinone oxidoreductase 1; two-electron reduction of quinones | Protection against carcinogenesis; NRF2 target; prodrug activation in cancer [2,4,5] |
| PYROXD1 | NAD(P)H-dependent oxidoreductase that sustains tRNA ligase activity | Pre-tRNA splicing and unfolded protein response; antioxidant use of NAD(P)+ |
| NRF2 (NFE2L2) | Transcription factor regulating NQO1 and other antioxidant genes | Master regulator of antioxidant response; altered in non-communicable diseases [1,4,7] |
| AHR | Aryl hydrocarbon receptor regulating NQO1 expression | Xenobiotic response and carcinogenesis |
| HO1 (HMOX1) | Heme oxygenase 1, part of Nrf2/HO1/NQO1 axis | Antioxidant defense in fibromyalgia |
| GDH (gdhA) | NAD(P)H-utilizing glutamate dehydrogenase in Bacteroides thetaiotaomicron | Bacterial redox metabolism; enzyme family I |
| KEAP1 | Negative regulator of NRF2 | Controls NQO1 induction via NRF2 [4,7] |
| NQO2 | Quinone oxidoreductase 2 (NRH-dependent) | Related quinone detoxification; context for NQO1 studies |
| TXNRD1 | Thioredoxin reductase 1 | NADPH-dependent redox control |
| GPX4 | Glutathione peroxidase 4 | Lipid peroxidation defense; ferroptosis |
| G6PD | Glucose-6-phosphate dehydrogenase | Generates NADPH for oxidoreductase reactions |
| IDH1/IDH2 | Isocitrate dehydrogenases | NADPH production for redox homeostasis |
| ME1 | Malic enzyme 1 | NADPH generation supporting oxidoreductase activity |
| SLC7A11 | Cystine/glutamate antiporter | Supports glutathione synthesis for redox balance |
| NFE2L2 (NRF2) target genes | Broad antioxidant program | Context for GO:0016651 regulation |
| BACH1 | BTB domain and CNC homolog 1 | Competes with NRF2 at antioxidant response elements |
How Is oxidoreductase activity, acting on NAD(P)H Regulated?
GO:0016651 activity is regulated at multiple levels. Transcriptionally, NQO1 is induced by NRF2 through the antioxidant response element, and this regulation involves the aryl hydrocarbon receptor basic helix-loop-helix transcription factors. NRF2 signalling is altered in systemic redox imbalance and non-communicable diseases, indicating that the pathway is responsive to chronic oxidative stress. In fibromyalgia, nutritional modulation of the Nrf2/HO1/NQO1 axis has been proposed to enhance antioxidant defense. At the protein level, PYROXD1 uses NAD(P)+ as an antioxidant to sustain tRNA ligase activity, suggesting that cofactor availability and redox state directly tune this activity during pre-tRNA splicing and the unfolded protein response. In bacteria, NAD(P)H-utilizing glutamate dehydrogenase activity is affected by trans-acting gene(s) positioned downstream of gdhA, illustrating genetic regulation of this activity.
oxidoreductase activity, acting on NAD(P)H and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NQO1 | Cancer chemoprevention and prodrug activation | NQO1 knockout and overexpression cell lines; NRF2-high PDAC models [4,5] |
| NRF2 (NFE2L2) | Systemic redox imbalance; non-communicable diseases | NRF2 knockout and knock-in reporter cells |
| PYROXD1 | tRNA splicing and unfolded protein response | PYROXD1 knockout cells with tRNA ligase assays |
| HO1 (HMOX1) | Fibromyalgia antioxidant defense | Nrf2/HO1/NQO1 axis modulation in cell models |
| GPX4 | Lipid peroxidation and ferroptosis in cancer | GPX4 knockout and point-mutation models |
Cancer and chemoprevention
NQO1, a prototypical GO:0016651 enzyme, contributes to protection against carcinogenesis and is regulated by NRF2 and the aryl hydrocarbon receptor. In NRF2-high pancreatic ductal adenocarcinoma, NQO1 activity can be exploited to activate selective prodrugs, demonstrating a therapeutic strategy built on this oxidoreductase activity. Targeting lipid peroxidation pathways, in which NADPH-dependent oxidoreductases participate, is also being explored for cancer treatment.
Fibromyalgia and oxidative stress
Neuronutritional enhancement of the antioxidant defense system through the Nrf2/HO1/NQO1 axis has been studied in fibromyalgia, linking GO:0016651-related enzymes to symptom biology and redox imbalance. This suggests that modulating NAD(P)H-dependent oxidoreductase activity may have clinical relevance in chronic pain conditions characterized by oxidative stress.
Systemic redox imbalance and non-communicable diseases
Altered NRF2 signalling is observed in systemic redox imbalance across non-communicable diseases, implicating NAD(P)H-dependent oxidoreductases in disease pathophysiology. Because NQO1 is a canonical NRF2 target, changes in GO:0016651 activity may serve as a readout of pathway activation in these conditions [4,7].
RNA processing and proteostasis disorders
PYROXD1 uses NAD(P)+ as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and the unfolded protein response, connecting GO:0016651 to RNA processing and proteostasis. Defects in this activity could therefore impact diseases linked to tRNA splicing or ER stress, although specific human disorders require further study.
From oxidoreductase activity, acting on NAD(P)H-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of NQO1 increase sensitivity to quinone-induced oxidative stress? | NQO1 knockout cell line [2,4] |
| Can NQO1 activity be exploited to activate prodrugs in NRF2-high tumors? | NQO1 overexpression and knockout in pancreatic cancer cells |
| How does PYROXD1 support tRNA ligase activity under ER stress? | PYROXD1 knockout with pre-tRNA splicing and UPR readouts |
| What is the effect of NRF2 pathway activation on GO:0016651 genes? | NRF2 knock-in or knockout reporter cells [4,7] |
| Does NAD(P)H-utilizing glutamate dehydrogenase activity depend on downstream trans-acting genes? | Bacterial gdhA mutant and complementation models |
| Can antioxidant defense be enhanced through the Nrf2/HO1/NQO1 axis? | Cell models treated with neuronutritional compounds |
How to Study the oxidoreductase activity, acting on NAD(P)H Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NAD(P)H oxidation assay | Enzymatic consumption of NADH/NADPH | Quantifying oxidoreductase activity [2,8] |
| Antioxidant response element reporter | NRF2-dependent transcriptional activity | Monitoring NQO1 induction [4,7] |
| qPCR/Western blot for NQO1 | NQO1 mRNA and protein levels | Pathway activation in disease models [1,4] |
| CRISPR knockout | Loss-of-function phenotype | Testing causal roles of NQO1, PYROXD1 [5,6] |
| CRISPR knock-in | Tagged or mutant enzyme expression | Localization and interaction studies |
| Lipid peroxidation assay | Oxidative damage to lipids | Cancer and ferroptosis research |
| tRNA splicing assay | Pre-tRNA processing efficiency | PYROXD1 function |
| Bacterial genetics | gdhA-linked activity | Microbial redox metabolism |
Enzymatic activity assays
Direct measurement of NAD(P)H oxidation (for example, by following absorbance at 340 nm) is the classic way to quantify GO:0016651 activity. Such assays have been used to characterize NQO1 and bacterial NAD(P)H-utilizing glutamate dehydrogenases [2,8]. Coupling to specific acceptors, such as quinones, allows discrimination among family members.
Transcriptional and pathway reporters
Because NQO1 is a canonical NRF2 target, antioxidant response element reporter assays and NQO1 mRNA/protein measurements are widely used to monitor pathway activation [4,7]. These methods are useful in studies of fibromyalgia and non-communicable diseases where NRF2 signalling is altered [1,7].
CRISPR-based genetic perturbation
Knockout, point-mutation, and knock-in models allow causal testing of individual oxidoreductases. For example, NQO1 knockout and overexpression have been used to evaluate prodrug activation in NRF2-high pancreatic ductal adenocarcinoma. PYROXD1 knockout models help dissect its role in tRNA splicing and the unfolded protein response.
Redox and lipid peroxidation profiling
Measuring lipid peroxidation and redox state provides functional context for GO:0016651 activity, especially in cancer and oxidative stress research. These readouts complement genetic models by linking enzyme activity to downstream cellular phenotypes [3,7].
How CRISPR Can Be Used to Study GO:0016651 oxidoreductase activity, acting on NAD(P)H
Knockout
CRISPR knockout of NQO1 or PYROXD1 enables loss-of-function studies to test their contribution to oxidative stress resistance, prodrug activation, and tRNA splicing [5,6]. Knockout models are essential for distinguishing the roles of individual GO:0016651 family members.
Point Mutation
Point mutations can be introduced into catalytic residues or cofactor-binding sites to dissect the mechanism of hydride transfer and to model disease-associated variants. Such approaches complement enzymatic assays of NAD(P)H-dependent oxidoreductases [2,6].
Knock-in
Knock-in of tagged or reporter alleles allows tracking of NQO1 or PYROXD1 expression and localization in live cells. This is particularly useful for studying NRF2-driven induction of NQO1 in cancer and redox imbalance models [4,5,7].
Overexpression
Overexpression of NQO1 can sensitize NRF2-high cancer cells to prodrugs, as demonstrated in pancreatic ductal adenocarcinoma models. Overexpression is also used to test whether increased NAD(P)H-dependent oxidoreductase activity enhances antioxidant defense [1,5].
How EDITGENE Supports oxidoreductase activity, acting on NAD(P)H Research
Researchers studying oxidoreductase activity, acting on NAD(P)H-related genes often need to determine whether a candidate gene is causally involved in redox regulation, drug response, or disease phenotypes. EDITGENE provides the CRISPR tools and bioinformatics support required to move from correlation to causation in this enzyme family.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on NAD(P)H research.
Frequently Asked Questions About oxidoreductase activity, acting on NAD(P)H
What is GO:0016651?
GO:0016651 is the Gene Ontology molecular function term for oxidoreductase activity, acting on NAD(P)H, meaning catalysis of a redox reaction in which NADH or NADPH is the hydrogen or electron donor.
What genes are involved in oxidoreductase activity, acting on NAD(P)H?
Key genes include NQO1, PYROXD1, and bacterial gdhA, with NRF2 (NFE2L2) and AHR regulating NQO1 expression [2,4,6,8].
What does NAD(P)H dehydrogenase mean?
NAD(P)H dehydrogenase is a synonym for GO:0016651, describing enzymes that use NADH or NADPH to reduce an acceptor.
How is NQO1 related to GO:0016651?
NQO1 is a prototypical NAD(P)H:quinone oxidoreductase that carries out GO:0016651 activity and protects against carcinogenesis [2,4].
Why is oxidoreductase activity, acting on NAD(P)H important in cancer?
It contributes to antioxidant defense and can activate prodrugs in NRF2-high tumors such as pancreatic ductal adenocarcinoma [4,5].
What diseases are linked to NAD(P)H-dependent oxidoreductases?
They are linked to cancer, fibromyalgia, and systemic redox imbalance in non-communicable diseases [1,3,5,7].
How can I study GO:0016651 in the lab?
Common methods include NAD(P)H oxidation assays, NRF2 reporter assays, and CRISPR knockout or overexpression of genes such as NQO1 and PYROXD1 [2,5,6].
What is the role of PYROXD1 in this activity?
PYROXD1 uses NAD(P)+ as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and the unfolded protein response.
Is GO:0016651 conserved in bacteria?
Yes, NAD(P)H-utilizing glutamate dehydrogenase in Bacteroides thetaiotaomicron belongs to enzyme family I and exhibits this activity.
How does NRF2 regulate GO:0016651 genes?
NRF2 induces NQO1 through the antioxidant response element, linking this activity to antioxidant defense [4,7].
Conclusion
GO:0016651, oxidoreductase activity, acting on NAD(P)H, defines a broad and biologically central class of redox enzymes. From NQO1-mediated quinone detoxification and cancer prodrug activation to PYROXD1-dependent tRNA splicing and bacterial glutamate dehydrogenases, this activity spans detoxification, biosynthesis, and stress responses [2,4,5,6,8]. Its tight regulation by NRF2 and its dysregulation in cancer, fibromyalgia, and non-communicable diseases make it a high-value target for mechanistic and translational research [1,3,7]. CRISPR-based knockout, point-mutation, knock-in, and overexpression models, combined with enzymatic and pathway assays, provide the experimental framework needed to move this field forward.
References
- 1. Inferrera F et al.. 2025. Neuronutritional enhancement of antioxidant defense system through Nrf2/HO1/NQO1 axis in fibromyalgia.. Neurochem Int 190:106057 PMID: 40997946
- 2. Preethi S et al.. 2022. Review on NAD(P)H dehydrogenase quinone 1 (NQO1) pathway.. Mol Biol Rep 49(9):8907-8924 PMID: 35347544
- 3. Clemente SM et al.. 2020. Targeting Lipid Peroxidation for Cancer Treatment.. Molecules 25(21) PMID: 33167334
- 4. Nioi P et al.. 2004. Contribution of NAD(P)H:quinone oxidoreductase 1 to protection against carcinogenesis, and regulation of its gene by the Nrf2 basic-region leucine zipper and the arylhydrocarbon receptor basic helix-loop-helix transcription factors.. Mutat Res 555(1-2):149-71 PMID: 15476858
- 5. Antonucci L et al.. 2026. Selective targeting of NRF2-high pancreatic ductal adenocarcinoma with an NQO1-activatable prodrug.. Proc Natl Acad Sci U S A 123(4):e2511733123 PMID: 41564125
- 6. Asanović I et al.. 2021. The oxidoreductase PYROXD1 uses NAD(P)(+) as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and unfolded protein response.. Mol Cell 81(12):2520-2532.e16 PMID: 33930333
- 7. Jakubowska M et al.. 2025. Altered NRF2 signalling in systemic redox imbalance: Insights from non-communicable diseases.. Redox Biol 87:103891 PMID: 41109135
- 8. Baggio L et al.. 1996. The NAD(P)H-utilizing glutamate dehydrogenase of Bacteroides thetaiotaomicron belongs to enzyme family I, and its activity is affected by trans-acting gene(s) positioned downstream of gdhA.. J Bacteriol 178(24):7212-20 PMID: 8955404
