GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016616 describes a molecular function: catalysis of a redox reaction in which a CH-OH group donates hydrogen/electrons and NAD+ or NADP is reduced.
• This activity is central to NADPH and NADH homeostasis, which fuels biosynthesis, antioxidant defense, and mitochondrial metabolism.
• Key enzymes include NAD kinases (NADK) that generate NADP(H), and dehydrogenases that use NAD+ or NADP as acceptor.
• NADPH produced by these reactions supports proline biosynthesis, fatty acid synthesis, and lipoylation in mitochondria.
• Dysregulation of NAD(P)(H) balance is linked to cancer, metabolic disorders, and developmental defects.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect gene function within this GO term.
Description
GO:0016616, oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor, is a molecular function term that defines a specific class of redox reactions. In these reactions, a hydroxyl-bearing carbon (CH-OH) is oxidized, transferring electrons to NAD+ or NADP, which are reduced to NADH or NADPH, respectively. This activity is fundamental to cellular metabolism, as it directly couples the oxidation of alcohols, sugars, and other metabolites to the generation of reducing equivalents that power biosynthesis and antioxidant systems. The term is distinct from other oxidoreductase activities because it strictly requires NAD+ or NADP as the electron acceptor and a CH-OH group as the donor. Researchers study GO:0016616 to understand how cells maintain redox balance, synthesize essential biomolecules, and respond to metabolic stress. For example, mitochondrial NADP(H) generation by enzymes with this activity is essential for proline biosynthesis, linking redox metabolism to amino acid production. Similarly, mitochondrial NADPH produced by these reactions fuels fatty acid synthesis and protein lipoylation, which are critical for oxidative metabolism. The NAD kinase family, which synthesizes NADP from NAD+, is a key upstream regulator of this activity, and its dysfunction has been implicated in cancer and metabolic diseases. Given the broad impact of this GO term on cell physiology, it is a frequent target for functional genomics. CRISPR-based models allow precise manipulation of genes encoding these enzymes, enabling researchers to test causality in disease contexts and to identify therapeutic vulnerabilities.
oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor At A Glance
| GO ID | GO:0016616 |
|---|---|
| GO term | oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor |
| Ontology | molecular_function |
| Synonym | None |
| Major function | Catalysis of redox reactions where a CH-OH group donates electrons to NAD+ or NADP |
| Donor substrate | CH-OH group (alcohol, hydroxyl-bearing metabolite) |
| Acceptor | NAD+ or NADP |
| Products | Oxidized donor and NADH or NADPH |
| Related enzymes | Dehydrogenases, NAD kinases (upstream), and other oxidoreductases |
What Is GO:0016616?
According to the Gene Ontology, GO:0016616 is defined as: Catalysis of an oxidation-reduction (redox) reaction in which a CH-OH group acts as a hydrogen or electron donor and reduces NAD+ or NADP. In simpler terms, it is an enzymatic activity that removes electrons from a molecule containing a CH-OH group and transfers them to NAD+ or NADP, producing NADH or NADPH. This definition captures a wide range of dehydrogenases and oxidoreductases that share this specific donor-acceptor pair.
Why Is oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Important in Cell Biology?
GO:0016616 is critically important because it governs the production of NADH and NADPH, which are central to energy metabolism, biosynthesis, and cellular defense against oxidative stress. NADPH, in particular, is required for reductive biosynthesis of fatty acids, cholesterol, and nucleotides, and for maintaining glutathione in its reduced state. Disruption of these reactions leads to metabolic imbalances that underlie cancer, neurodegeneration, and developmental disorders. Thus, understanding this activity provides mechanistic insights into disease and identifies potential drug targets.
• Maintains cellular redox balance by generating NADH and NADPH.
• Supports proline biosynthesis in mitochondria, linking redox to amino acid metabolism.
• Fuels mitochondrial fatty acid synthesis and protein lipoylation for oxidative metabolism.
• Provides NADPH for antioxidant systems, protecting against oxidative damage.
• Regulates folate-dependent nucleotide synthesis through cytosolic NADK.
• Implicated in cancer cell proliferation and survival via NAD+ kinase activity.
• Plays a role in plant chloroplast NAD(P)(H) balance and photosynthesis.
• Essential for metabolic adaptation to stress and nutrient availability.
• Target for therapeutic intervention in metabolic disorders and cancer.
• Provides a functional readout for CRISPR screens targeting metabolic genes.
Molecular Mechanism of oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
Substrate Recognition and Binding
In simple terms: The enzyme grabs a molecule that has a CH-OH group and positions it next to NAD+ or NADP.
Enzymes with GO:0016616 activity possess a Rossmann-fold or similar nucleotide-binding domain that binds NAD+ or NADP with high specificity. The CH-OH substrate is accommodated in a pocket where the hydroxyl group is oriented for hydride transfer. For example, mitochondrial NADP(H)-dependent enzymes recognize proline precursors and fatty acid substrates, ensuring efficient catalysis.
Hydride Transfer and Redox Chemistry
In simple terms: The enzyme removes a hydride ion from the CH-OH group and hands it to NAD+ or NADP.
The catalytic mechanism involves a direct hydride transfer from the carbon bearing the hydroxyl group to the nicotinamide ring of NAD+ or NADP. This step is often facilitated by a general base that deprotonates the hydroxyl, stabilizing the transition state. The reaction is stereospecific and can be reversible depending on cellular redox potential.
Cofactor Regeneration and NADK Role
In simple terms: NAD kinase makes more NADP, which is needed for the reaction to continue.
NAD kinase (NADK) phosphorylates NAD+ to generate NADP, the preferred cofactor for many GO:0016616 enzymes. Human NADK is regulated by calcium/calmodulin and is essential for maintaining NADPH pools. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, highlighting its role in supplying NADP for these oxidoreductases.
Compartmentalization and Metabolic Integration
In simple terms: These reactions happen in different parts of the cell, like mitochondria and cytosol, to meet local needs.
GO:0016616 activities are distributed across mitochondria, cytosol, and chloroplasts. Mitochondrial NADPH generated by these enzymes supports proline biosynthesis and fatty acid synthesis. In chloroplasts, NADP(H) phosphatases like CCR4C regulate the balance of NADP and NADPH, impacting photosynthesis. This compartmentalization allows cells to tailor redox metabolism to specific biosynthetic demands.
Regulation by Cellular Signals
In simple terms: The cell can speed up or slow down these reactions based on its needs.
The activity of GO:0016616 enzymes is regulated at multiple levels, including gene expression, post-translational modification, and allosteric control by NAD(P)(H) ratios. For instance, NADK activity is modulated by calcium signaling and phosphorylation, affecting NADP availability. In cancer, NADK is often upregulated to support increased NADPH demand for proliferation and antioxidant defense.
Key Genes Involved in GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
The following genes encode enzymes and regulators that carry out or directly support GO:0016616 activity, as evidenced by published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NADK | Phosphorylates NAD+ to NADP, supplying cofactor for GO:0016616 enzymes | Target in cancer; regulates NADPH pools |
| PRODH | Proline dehydrogenase, oxidizes proline using NAD+ or NADP | Links redox to proline metabolism |
| PYCR1 | Pyrroline-5-carboxylate reductase, uses NADPH to synthesize proline | Mitochondrial proline biosynthesis |
| MTHFD2 | Methylenetetrahydrofolate dehydrogenase, uses NAD+ or NADP | Folate metabolism and nucleotide synthesis |
| FASN | Fatty acid synthase, uses NADPH for fatty acid synthesis | Mitochondrial fatty acid synthesis and lipoylation |
| LIAS | Lipoyl synthase, requires NADPH for lipoylation | Mitochondrial oxidative metabolism |
| CCR4C | Chloroplast NADP(H) phosphatase, regulates NAD(P)(H) balance | Plant photosynthesis and redox homeostasis |
| G6PD | Glucose-6-phosphate dehydrogenase, produces NADPH | Antioxidant defense and pentose phosphate pathway |
| IDH1 | Isocitrate dehydrogenase 1, produces NADPH in cytosol | Cancer metabolism and redox balance |
| IDH2 | Isocitrate dehydrogenase 2, produces NADPH in mitochondria | Mitochondrial redox and proline synthesis |
| ME1 | Malic enzyme 1, produces NADPH | Lipogenesis and redox homeostasis |
| ME2 | Malic enzyme 2, produces NADPH in mitochondria | Mitochondrial metabolism |
| NADK2 | Mitochondrial NAD kinase, generates NADP | Mitochondrial NADPH for biosynthesis |
| ALDH1A1 | Aldehyde dehydrogenase, oxidizes aldehydes using NAD+ | Cancer stem cells and drug resistance |
| LDHB | Lactate dehydrogenase B, interconverts lactate and pyruvate using NAD+ | Metabolic reprogramming in cancer |
| PHGDH | Phosphoglycerate dehydrogenase, uses NAD+ for serine synthesis | Serine biosynthesis and cancer |
How Is oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Regulated?
The activity of GO:0016616 enzymes is tightly regulated to meet cellular demands for NADH and NADPH. NAD kinase (NADK) is a key upstream regulator, as it produces NADP, the substrate for many of these enzymes. Human NADK is activated by calcium/calmodulin and is subject to phosphorylation, allowing rapid adaptation to changes in calcium signaling and energy status. In cancer cells, NADK is often overexpressed to sustain high NADPH levels required for proliferation and antioxidant defense. Additionally, the expression of dehydrogenases such as PYCR1, MTHFD2, and FASN is controlled by oncogenic transcription factors and metabolic stress pathways, ensuring that NADPH production matches biosynthetic needs. In plants, CCR4C regulates NADP(H) balance in chloroplasts, affecting photosynthesis and stress responses.
oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NADK | Cancer proliferation and redox balance | Knockout and overexpression in cancer cell lines |
| PYCR1 | Proline biosynthesis defects, cutis laxa | Point mutation knock-in in fibroblasts |
| MTHFD2 | Folate-dependent nucleotide synthesis in cancer | CRISPR knockout in tumor cells |
| FASN | Mitochondrial fatty acid synthesis and lipoylation | Knockout in hepatocytes |
| CCR4C | Plant photosynthesis and redox homeostasis | Knockout in Arabidopsis |
Cancer Metabolism and NADPH Dependency
Many cancers reprogram metabolism to increase NADPH production, which supports rapid proliferation and protects against oxidative stress. NAD+ kinase, which supplies NADP for GO:0016616 enzymes, is upregulated in several cancers and is considered a therapeutic target. Enzymes such as G6PD, IDH1, and ME1 are also frequently altered in tumors, contributing to NADPH pools. Inhibiting these pathways may selectively kill cancer cells that are dependent on high NADPH levels.
Mitochondrial Dysfunction and Metabolic Disorders
Mitochondrial NADPH generated by GO:0016616 activities is essential for proline biosynthesis and fatty acid synthesis. Defects in these pathways can lead to metabolic disorders, including hyperprolinemia and lipoylation defects. For example, loss of mitochondrial NADP(H) generation impairs proline synthesis, affecting collagen production and redox balance. Similarly, reduced mitochondrial NADPH fuels fatty acid synthesis and lipoylation, and its disruption compromises oxidative metabolism.
Neurodegeneration and Oxidative Stress
NADPH is critical for regenerating reduced glutathione, a major antioxidant in the brain. Impaired GO:0016616 activity can lead to oxidative stress and neuronal damage, contributing to neurodegenerative diseases. Although direct evidence is limited, the role of NADPH in antioxidant defense suggests that dysfunction in these enzymes may exacerbate conditions like Alzheimer's and Parkinson's diseases.
Plant Development and Photosynthesis
In plants, GO:0016616 enzymes participate in chloroplast redox balance. CCR4C, a chloroplast-localized NADP(H) phosphatase, regulates NAD(P)(H) levels and affects photosynthesis and plant growth. The light reactions of photosynthesis themselves involve NADP reduction, highlighting the evolutionary conservation of this activity.
From oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of NADK impair NADPH production? | NADK knockout cell line |
| Does a point mutation in PYCR1 affect proline synthesis? | PYCR1 point-mutation knock-in |
| Can overexpression of MTHFD2 rescue folate deficiency? | MTHFD2 overexpression |
| How does FASN knockout affect lipoylation? | FASN knockout in mitochondria |
| Does CCR4C regulate chloroplast NADP(H) balance? | CCR4C knockout in Arabidopsis |
| Is NADK required for cancer cell survival? | NADK knockout in cancer cells |
How to Study the oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screen | Gene essentiality and fitness | Identify metabolic vulnerabilities |
| Metabolomics | NADPH/NADH levels and pathway flux | Validate redox changes |
| Enzymatic assay | Dehydrogenase activity | Confirm enzyme function |
| Cryo-EM | Protein structure and conformational changes | Mechanistic studies |
| RNA-seq | Gene expression changes | Assess transcriptional regulation |
| Proteomics | Protein abundance and modifications | Identify post-translational regulation |
| Isotope tracing | Metabolic flux | Quantify proline and fatty acid synthesis |
| Immunoblotting | Protein levels | Validate knockout or overexpression |
CRISPR Screens for Metabolic Vulnerabilities
Genome-wide CRISPR knockout screens can identify genes with GO:0016616 activity that are essential for cell growth under specific conditions, such as low glucose or oxidative stress. For example, screens in cancer cells have revealed NADK as a conditional dependency. These screens use libraries targeting all metabolic enzymes and measure cell fitness by sequencing.
Metabolomics and Flux Analysis
Mass spectrometry-based metabolomics quantifies NADPH, NADH, and related metabolites to assess GO:0016616 activity. Isotope tracing can measure flux through proline and fatty acid synthesis pathways. This approach validates findings from genetic screens and provides mechanistic insights.
Enzymatic Assays for Dehydrogenase Activity
In vitro assays using purified enzymes or cell lysates measure the reduction of NAD+ or NADP to NADH or NADPH by monitoring absorbance at 340 nm. These assays are used to confirm the activity of candidate enzymes and to test inhibitors.
Structural Biology and Cryo-EM
Cryo-EM and X-ray crystallography provide high-resolution structures of enzymes with GO:0016616 activity, revealing substrate binding and catalytic mechanisms. For example, the cryo-EM structure of human NAD kinase has elucidated its regulation. These structures guide drug design.
How CRISPR Can Be Used to Study GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
Knockout
CRISPR knockout of genes encoding GO:0016616 enzymes, such as NADK or PYCR1, allows researchers to assess loss-of-function phenotypes. For example, NADK knockout reduces NADP levels and impairs proliferation in cancer cells. Knockout models are essential for validating metabolic dependencies.
Point Mutation
Point mutations can mimic disease-associated variants or alter catalytic residues. For instance, knock-in of a catalytically dead PYCR1 mutant can distinguish between enzymatic activity and structural roles. This approach is valuable for studying inherited metabolic disorders.
Knock-in
Knock-in of tagged versions of GO:0016616 enzymes (e.g., GFP or HA) enables localization and interaction studies. Tagged NADK can be used to monitor its subcellular distribution and regulation. Knock-in of reporter genes can also track pathway activity.
Overexpression
Overexpression of genes like MTHFD2 or FASN can rescue metabolic defects or drive oncogenic transformation. For example, MTHFD2 overexpression supports folate-dependent nucleotide synthesis under stress. Overexpression models help identify sufficiency in metabolic pathways.
How EDITGENE Supports oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Research
Researchers studying oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor-related genes often need to determine whether a candidate gene is causally involved in a specific metabolic or disease phenotype. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models, enabling rigorous functional validation of genes within this GO term.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor research.
Frequently Asked Questions About oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
What is GO:0016616?
GO:0016616 is a Gene Ontology molecular function term that describes oxidoreductase activity acting on a CH-OH group of donors with NAD+ or NADP as the electron acceptor.
What genes are involved in oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor?
Genes include NADK, PYCR1, MTHFD2, FASN, G6PD, IDH1, IDH2, ME1, ME2, and others that encode dehydrogenases or NAD kinases.
How does NADK relate to GO:0016616?
NADK phosphorylates NAD+ to NADP, providing the essential cofactor for many GO:0016616 enzymes, thereby regulating their activity.
Why is NADPH important for this GO term?
NADPH is the reduced product of NADP in these reactions and is required for reductive biosynthesis and antioxidant defense.
What diseases are linked to GO:0016616 dysfunction?
Dysfunction is linked to cancer, metabolic disorders, and potentially neurodegeneration due to impaired redox balance.
How can I study GO:0016616 in the lab?
Common methods include CRISPR knockout, enzymatic assays, metabolomics, and structural biology.
What is the role of mitochondrial NADPH in proline synthesis?
Mitochondrial NADPH generated by GO:0016616 enzymes is essential for proline biosynthesis, as shown by loss of PYCR1 activity.
Does GO:0016616 play a role in fatty acid synthesis?
Yes, mitochondrial NADPH fuels fatty acid synthesis and lipoylation, which are critical for oxidative metabolism.
How is NADK regulated?
NADK is regulated by calcium/calmodulin and phosphorylation, and its expression is often increased in cancer.
Can CRISPR screens identify new genes with GO:0016616 activity?
Yes, genome-wide CRISPR screens can identify genes required for NADPH production and redox homeostasis.
Conclusion
GO:0016616 represents a fundamental molecular function that couples the oxidation of CH-OH groups to the reduction of NAD+ or NADP, thereby generating NADH and NADPH. These reducing equivalents are indispensable for biosynthesis, antioxidant defense, and metabolic adaptation. The enzymes carrying this activity, including NAD kinases and dehydrogenases, are implicated in cancer, metabolic disorders, and plant development. CRISPR-based models provide powerful tools to dissect their functions and to identify therapeutic targets. EDITGENE offers comprehensive services to support research on this critical GO term.
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. Praharaj PP et al.. 2025. Cryo-EM structure and regulation of human NAD kinase.. Sci Adv 11(4):eads2664 PMID: 39854463
- 5. Arnon DI. 1971. The light reactions of photosynthesis.. Proc Natl Acad Sci U S A 68(11):2883-92 PMID: 4400251
- 6. Flickinger KM et al.. 2025. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis.. Nat Metab 7(6):1150-1167 PMID: 40316835
- 7. 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
- 8. Tedeschi PM et al.. 2016. NAD+ Kinase as a Therapeutic Target in Cancer.. Clin Cancer Res 22(21):5189-5195 PMID: 27582489
