GO:0016723 oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016723 describes an oxidoreductase activity in which a metal ion is reduced while NAD+ or NADP+ serves as the electron acceptor.
• This activity is central to maintaining cellular redox balance and supplying reducing equivalents for biosynthesis and antioxidant defense.
• Key enzymes include NAD kinases (NADK, NADK2) that generate NADP(H), and metal-containing reductases that couple metal reduction to NAD(P)+ reduction.
• Mitochondrial NADP(H) metabolism, driven by NADK2, is essential for proline biosynthesis and fatty acid synthesis.
• Dysregulation of NAD(P)(H) balance is linked to metabolic disorders, cancer, and inflammatory diseases.
• CRISPR knockout, point-mutation, and overexpression models are powerful tools to dissect the roles of genes encoding these enzymes.
Description
GO:0016723, oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor, is a molecular function defined by the catalysis of an oxidation-reduction reaction in which a metal ion is reduced and NAD+ or NADP+ acts as the electron acceptor. This activity is fundamental to cellular redox homeostasis, as it links metal ion chemistry to the pyridine nucleotide pool, influencing processes ranging from biosynthesis to antioxidant defense. Researchers study this term to understand how cells balance reducing equivalents and how perturbations contribute to disease. The enzymes annotated with this activity often contain metal cofactors and utilize NAD(P)+ as a co-substrate, making them attractive targets for metabolic engineering and therapeutic intervention.
oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor At A Glance
| GO ID | GO:0016723 |
|---|---|
| GO term | oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor |
| Ontology | molecular_function |
| Synonym | oxidoreductase activity, oxidizing metal ions, NAD or NADP as acceptor; oxidoreductase activity, reducing metal ions, NAD or NADP as acceptor |
| Major function | Catalyzes reduction of metal ions using NAD+ or NADP+ as electron acceptor |
| Cofactors | Metal ions (e.g., iron, copper, manganese) and NAD(P)+ |
| Related processes | Redox homeostasis, biosynthesis, antioxidant defense |
| EC number | 1.-.-.- (oxidoreductases) |
What Is GO:0016723?
According to the Gene Ontology, GO:0016723 is defined as the catalysis of an oxidation-reduction reaction in which the metal ion is reduced and NAD+ or NADP+ acts as an electron acceptor. In other words, the enzyme transfers electrons from a donor (often another metal or organic substrate) to a metal ion, while simultaneously reducing NAD+ or NADP+ to NADH or NADPH. This dual reduction couples metal homeostasis with the cellular redox state.
Why Is oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor Important in Cell Biology?
This activity is crucial because it directly connects metal ion metabolism with the NAD(P)(H) pool, which is central to energy metabolism, biosynthesis, and cellular protection against oxidative stress. Dysregulation of enzymes carrying this activity can lead to metabolic imbalances that underlie diseases such as cancer, neurodegeneration, and inflammatory disorders. Understanding GO:0016723 helps researchers identify therapeutic targets and design metabolic interventions.
• Maintains redox balance by regenerating NAD(P)H and reducing metal ions.
• Supports biosynthesis of proline, fatty acids, and nucleotides.
• Protects cells from oxidative damage by coupling metal reduction to antioxidant systems.
• Regulates inflammatory responses in T cells via NAD/H synthesis.
• Implicated in cancer metabolism and tumor growth.
• Plays a role in mitochondrial function and lipoylation.
• Provides targets for antimicrobial and anticancer drug development.
• Enables metabolic engineering of redox pathways.
• Links to folate-dependent nucleotide synthesis.
• Influences chloroplast NAD(P)(H) balance in plants.
Molecular Mechanism of oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor
Substrate binding and metal ion coordination
In simple terms: The enzyme grabs the metal ion and the NAD(P)+ molecule to start the reaction.
Enzymes with this activity typically contain a metal-binding site where the metal ion is coordinated by amino acid residues such as cysteine, histidine, or aspartate. NAD(P)+ binds in a Rossmann-fold domain, positioning the nicotinamide ring for hydride transfer.
Electron transfer and metal reduction
In simple terms: Electrons are passed to the metal ion, changing its charge.
The enzyme facilitates electron transfer from a donor (often another metal or an organic substrate) to the metal ion, reducing it. Simultaneously, NAD(P)+ accepts electrons to form NAD(P)H. This coupled reaction is exemplified by NAD kinases, which phosphorylate NAD+ to NADP+ using ATP, though the metal reduction step is distinct.
NAD(P)+ reduction to NAD(P)H
In simple terms: NAD(P)+ picks up electrons and becomes NAD(P)H, a key reducing agent.
The reduction of NAD(P)+ to NAD(P)H is a central output of this activity. NADPH is particularly important for reductive biosynthesis and antioxidant defense. Mitochondrial NADP(H) generation by NADK2 is essential for proline biosynthesis and fatty acid synthesis.
Regulation by cellular redox state
In simple terms: The cell adjusts this activity based on its needs and stress levels.
The activity is regulated by the availability of NAD(P)+ and metal ions, as well as by post-translational modifications and expression levels of the enzymes. For instance, cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, linking redox regulation to one-carbon metabolism. Cytoplasmic NAD/H synthesis via NRK1 regulates inflammatory capacity in CD4+ T cells.
Key Genes Involved in GO:0016723 oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor
The following genes encode enzymes or regulators directly associated with GO:0016723, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NADK | Phosphorylates NAD+ to NADP+ | Central to NADP(H) production; knockout affects redox balance |
| NADK2 | Mitochondrial NAD kinase | Essential for proline and fatty acid synthesis |
| NRK1 | NAD/H synthesis via nicotinamide riboside | Regulates inflammatory capacity in T cells |
| CCR4C | Chloroplast NADP(H) phosphatase | Regulates NAD(P)(H) balance in Arabidopsis |
| MTHFD2 | Folate-dependent one-carbon metabolism | Linked to NADK conditionally essential for nucleotide synthesis |
| G6PD | Glucose-6-phosphate dehydrogenase | Generates NADPH; related to redox homeostasis |
| 6PGD | 6-phosphogluconate dehydrogenase | Generates NADPH in pentose phosphate pathway |
| IDH1 | Isocitrate dehydrogenase 1 | Produces NADPH in cytosol |
| IDH2 | Isocitrate dehydrogenase 2 | Produces NADPH in mitochondria |
| ME1 | Malic enzyme 1 | Generates NADPH from malate |
| ME2 | Malic enzyme 2 | Mitochondrial NADPH generation |
| NNT | Nicotinamide nucleotide transhydrogenase | Interconverts NADH and NADPH |
| GLRX | Glutaredoxin | Uses NADPH to reduce disulfides |
| TXNRD1 | Thioredoxin reductase 1 | NADPH-dependent reduction of thioredoxin |
| PRDX | Peroxiredoxin | Reduces peroxides using NADPH |
| SOD1 | Superoxide dismutase 1 | Copper/zinc enzyme; linked to metal ion reduction |
| SOD2 | Superoxide dismutase 2 | Manganese enzyme; mitochondrial redox |
How Is oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor Regulated?
The activity of enzymes with GO:0016723 is regulated at multiple levels. Transcriptionally, the expression of NADK and NADK2 is responsive to metabolic demands and stress. Post-translationally, NADK activity can be modulated by phosphorylation and redox modifications. Metabolically, the availability of NAD(P)+ and metal ions directly influences flux through these reactions. In mitochondria, NADP(H) integrates redox and metabolic signals, as reviewed by Zhang et al.. Additionally, cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, highlighting regulation by one-carbon metabolism. In T cells, NRK1-mediated NAD/H synthesis regulates inflammatory capacity, linking redox regulation to immune function.
oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NADK | Cancer proliferation | Knockout in cancer cell lines; xenograft models |
| NADK2 | Mitochondrial myopathy | Knockout mice; patient-derived fibroblasts |
| NRK1 | Autoimmune inflammation | T cell-specific knockout mice; colitis models |
| CCR4C | Plant redox balance | Arabidopsis knockout; stress response assays |
| MTHFD2 | Cancer and folate metabolism | Knockout in cancer cells; metabolic profiling |
Cancer metabolism
Altered NAD(P)(H) metabolism is a hallmark of cancer. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, supporting proliferation of cancer cells. Targeting NADK or related enzymes may disrupt redox balance and inhibit tumor growth.
Inflammatory diseases
Cytoplasmic NAD/H synthesis via NRK1 regulates inflammatory capacity and promotes survival of CD4+ T cells, suggesting that dysregulation of this pathway contributes to autoimmune and inflammatory conditions.
Metabolic disorders
Mitochondrial NADP(H) generation by NADK2 is essential for proline biosynthesis and fatty acid synthesis; defects lead to metabolic imbalances and mitochondrial dysfunction. These pathways are linked to lipoylation and oxidative metabolism.
Neurodegeneration
Redox imbalance and metal ion dyshomeostasis are implicated in neurodegenerative diseases. Enzymes with GO:0016723 activity help maintain metal ion homeostasis and NAD(P)H levels, protecting neurons from oxidative stress.
From oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does NADK loss affect cancer cell proliferation? | CRISPR knockout in HCT116 or HeLa cells |
| What is the role of NADK2 in mitochondrial metabolism? | Knockout mice or HepG2 cells |
| How does NRK1 regulate T cell inflammation? | T cell-specific knockout mice |
| Can point mutations in NADK alter its activity? | CRISPR point mutation knock-in in cell lines |
| Does overexpression of CCR4C alter chloroplast redox? | Arabidopsis overexpression lines |
| How does NADPH level affect lipoylation? | Knock-in of tagged NADK2 for proteomics |
How to Study the oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screening | Gene essentiality and redox sensitivity | Identify novel regulators of NAD(P)(H) metabolism |
| Metabolomics (LC-MS) | NAD(P)(H) and metal ion levels | Quantify pathway flux in knockout cells |
| Proteomics (AP-MS) | Protein interactions and modifications | Study enzyme complexes and regulation |
| Live-cell imaging | NAD(P)H dynamics | Monitor redox changes in real time |
| Enzymatic assays | Specific activity of oxidoreductases | Measure kinetic parameters of mutants |
| RNA-seq | Transcriptional changes | Assess compensatory gene expression |
| Ribo-seq | Translation efficiency | Study translational control of redox genes |
| ChIP-seq | Chromatin binding of transcription factors | Identify regulators of NADK expression |
CRISPR knockout screens
Genome-wide CRISPR knockout screens can identify genes whose loss affects redox balance or sensitivity to oxidative stress, revealing essential components of GO:0016723 pathways.
Metabolomics and flux analysis
Mass spectrometry-based metabolomics quantifies NAD(P)(H) levels and metal ion concentrations, providing direct readouts of enzyme activity.
Proteomics and interactomics
Affinity purification coupled to mass spectrometry can identify protein-protein interactions and post-translational modifications of enzymes with this activity.
Live-cell imaging of redox sensors
Genetically encoded fluorescent sensors (e.g., SoNar, iNap) allow real-time monitoring of NAD(P)H dynamics in living cells, linking activity to cellular physiology.
How CRISPR Can Be Used to Study GO:0016723 oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor
Knockout
CRISPR knockout of genes encoding enzymes with GO:0016723 activity, such as NADK or NADK2, can reveal their essentiality in cell proliferation, redox homeostasis, and metabolism. For example, NADK knockout sensitizes cancer cells to folate stress.
Point Mutation
Introducing point mutations in catalytic residues of NADK or metal-binding sites can dissect the enzymatic mechanism and separate metal reduction from NAD(P)+ reduction. Such models help validate structural predictions from cryo-EM.
Knock-in
Knock-in of tagged versions (e.g., FLAG, GFP) of NADK2 or CCR4C allows for localization and interaction studies in native contexts. This approach preserves endogenous regulation.
Overexpression
Overexpression of NADK or NRK1 can boost NADP(H) or NAD(H) levels, respectively, and is used to study the effects of enhanced redox capacity on cell survival and inflammation.
How EDITGENE Supports oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor Research
Researchers studying oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor-related genes often need to determine whether a candidate gene is causally involved in redox regulation, metabolic disease, or cancer. EDITGENE provides comprehensive CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor research.
Frequently Asked Questions About oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor
What is GO:0016723?
GO:0016723 is a Gene Ontology molecular function term describing oxidoreductase activity that reduces metal ions using NAD+ or NADP+ as the electron acceptor.
What genes are involved in oxidoreductase activity, acting on metal ions, NAD or NADP as acceptor?
Key genes include NADK, NADK2, NRK1, and CCR4C, which encode enzymes that generate NAD(P)(H) or reduce metal ions.
How is GO:0016723 related to NADPH production?
Enzymes with this activity often produce NADPH, a critical reducing agent for biosynthesis and antioxidant defense.
What diseases are associated with defects in this activity?
Dysregulation is linked to cancer, inflammatory diseases, and metabolic disorders.
What research methods are used to study GO:0016723?
Common methods include CRISPR knockout screens, metabolomics, proteomics, and live-cell imaging of NAD(P)H.
Can CRISPR be used to study oxidoreductase activity?
Yes, CRISPR knockout, point mutation, and overexpression models are widely used to dissect gene function in this pathway.
What is the role of NADK in this activity?
NADK phosphorylates NAD+ to NADP+, providing the substrate for NADP-dependent oxidoreductases.
How does mitochondrial NADP(H) relate to this term?
Mitochondrial NADP(H), generated by NADK2, fuels reductive biosynthesis and is essential for proline and fatty acid synthesis.
Is GO:0016723 involved in inflammation?
Yes, cytoplasmic NAD/H synthesis via NRK1 regulates inflammatory capacity in CD4+ T cells.
What model organisms are used to study this activity?
Human cell lines, mice, and Arabidopsis are commonly used, depending on the gene and pathway.
Conclusion
GO:0016723 represents a critical molecular function that couples metal ion reduction to NAD(P)+ reduction, impacting redox homeostasis, biosynthesis, and disease. Understanding its mechanisms and regulation offers insights into metabolic disorders and cancer, and provides targets for therapeutic intervention. EDITGENE's CRISPR services empower researchers to dissect these pathways with precision and scale.
References
- 1. Zhu J et al.. 2021. Mitochondrial NADP(H) generation is essential for proline biosynthesis.. Science 372(6545):968-972 PMID: 33888598
- 2. Kim D et al.. 2025. Mitochondrial NADPH fuels mitochondrial fatty acid synthesis and lipoylation to power oxidative metabolism.. Nat Cell Biol 27(5):790-800 PMID: 40258949
- 3. McGuinness ET et al.. 1985. NAD+ kinase--a review.. Int J Biochem 17(1):1-11 PMID: 2987053
- 4. Akashi K et al.. 2025. Identification of CCR4C as a chloroplast-localized NADP(H) phosphatase regulating NAD(P)(H) balance in Arabidopsis.. Proc Natl Acad Sci U S A 122(42):e2504605122 PMID: 41091769
- 5. Flickinger KM et al.. 2025. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis.. Nat Metab 7(6):1150-1167 PMID: 40316835
- 6. Stavrou V et al.. 2026. Cytoplasmic NAD/H synthesis via NRK1 regulates inflammatory capacity and promotes survival of CD4(+) T cells.. Nat Commun 17(1) PMID: 41639086
- 7. Praharaj PP et al.. 2025. Cryo-EM structure and regulation of human NAD kinase.. Sci Adv 11(4):eads2664 PMID: 39854463
- 8. Zhang R et al.. 2026. Mitochondrial NADP(H) integrates redox and metabolism.. Trends Endocrinol Metab 37(8):727-735 PMID: 41887981
