GO:0016620 oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016620 describes a molecular function: catalysis of a redox reaction in which an aldehyde or ketone (oxo) group donates electrons and NAD+ or NADP+ is the electron acceptor.
• The term is mechanistically linked to NAD(P)(H) homeostasis, because NAD and NADP are the obligate electron acceptors for these enzymes.
• NAD kinase (NADK) is a key upstream regulator that generates NADP(H), the reduced cofactor pool required by many NADP-dependent oxidoreductases.
• Enzymes annotated to this term participate in diverse pathways including proline biosynthesis, polyamine catabolism, and folate-dependent nucleotide synthesis.
• Dysregulation of NAD(P)-dependent redox reactions is implicated in cancer, metabolic disease, and renal failure.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal testing of genes encoding these oxidoreductases and their regulators.
Description
GO:0016620, oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor, is a molecular function term in the Gene Ontology that defines a specific class of redox enzymes. These enzymes catalyze oxidation-reduction reactions in which an aldehyde or ketone (oxo) group serves as the electron donor and NAD+ or NADP+ serves as the electron acceptor, thereby coupling substrate oxidation to pyridine nucleotide reduction. This functional class is central to cellular metabolism because it links carbon substrate oxidation to the generation of NADH and NADPH, which are required for biosynthesis, antioxidant defense, and energy transduction. Researchers study GO:0016620 because its member enzymes sit at the interface of catabolism and anabolism. For example, mitochondrial NADP(H) generation supports proline biosynthesis, a process dependent on NADP-dependent oxidoreductase chemistry. NAD kinase, which produces NADP(H), is a critical regulator of the cofactor pools that these enzymes consume. In cancer biology, spermine oxidase, an FAD-dependent enzyme that produces hydrogen peroxide and acrolein, illustrates how aldehyde/oxo chemistry can drive mutagenic and carcinogenic processes. From a methodological standpoint, GO:0016620 is a useful annotation for interpreting enzyme function in genome-scale datasets. Because the term specifies both the donor chemistry (aldehyde or oxo group) and the acceptor (NAD or NADP), it enables precise functional classification in proteomics, metabolomics, and CRISPR screening studies. This article summarizes the definition, mechanism, key genes, disease relevance, and experimental models for studying GO:0016620.
oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor At A Glance
| GO ID | GO:0016620 |
|---|---|
| GO term | oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor |
| Ontology | molecular_function |
| Synonym | none |
| Major function | Catalysis of redox reactions where an aldehyde or ketone (oxo) group donates electrons and NAD+ or NADP+ is reduced |
| Cofactor requirement | NAD+ or NADP+ as the electron acceptor |
| Substrate class | Aldehyde or ketone (oxo) group-containing compounds |
| Related cofactor metabolism | NAD kinase generates NADP(H), which supports NADP-dependent oxidoreductases |
| Representative pathways | Proline biosynthesis, polyamine catabolism, folate-dependent nucleotide synthesis |
What Is GO:0016620?
GO:0016620 is a molecular function term describing catalysis of an oxidation-reduction (redox) reaction in which an aldehyde or ketone (oxo) group acts as a hydrogen or electron donor and reduces NAD+ or NADP+. In practical terms, the enzyme removes electrons from an aldehyde or ketone substrate and transfers them to a pyridine nucleotide acceptor, converting NAD(P)+ to NAD(P)H. This definition distinguishes the term from other oxidoreductase activities that use different donors (e.g., CH-CH groups) or different acceptors (e.g., oxygen, disulfides, quinones).
Why Is oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor Important in Cell Biology?
GO:0016620 is important because it defines a large and metabolically central class of enzymes that couple aldehyde or ketone oxidation to NAD(P)+ reduction, thereby influencing redox balance, biosynthesis, and detoxification. These reactions are essential for maintaining NADPH pools used in reductive biosynthesis and antioxidant defense, and for generating NADH that feeds oxidative phosphorylation. Dysregulation of these enzymes or their cofactor supply is linked to cancer, metabolic disorders, and renal pathology. Consequently, GO:0016620 provides a functional framework for interpreting genetic and pharmacological perturbations of redox metabolism.
• Defines a major redox enzyme class that uses NAD+ or NADP+ as the electron acceptor.
• Connects aldehyde/ketone metabolism to NAD(P)H production, which is required for biosynthesis and antioxidant defense.
• NAD kinase regulates the NADP(H) pool that feeds NADP-dependent oxidoreductases.
• Enzymes in this class participate in proline biosynthesis, which supports cancer cell growth.
• Spermine oxidase, an aldehyde/oxo redox enzyme, produces acrolein and drives gastric carcinogenesis.
• Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis.
• NADP(H) phosphatases such as CCR4C regulate NAD(P)(H) balance in plants, showing evolutionary conservation.
• Polyamine catabolism and renal failure are linked to altered polyamine and redox metabolism.
• The term aids functional annotation in proteomics and CRISPR screening datasets.
• Provides a mechanistic basis for targeting redox enzymes in cancer and metabolic disease.
Molecular Mechanism of oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor
Substrate recognition and donor chemistry
In simple terms: The enzyme first grabs a molecule that has an aldehyde or ketone group, which will give up electrons.
Enzymes annotated to GO:0016620 bind substrates containing an aldehyde or ketone (oxo) group, positioning the carbonyl carbon for hydride transfer. The donor chemistry is defined by the oxidation of this carbonyl-containing group, which distinguishes the term from oxidoreductases acting on CH-CH or CH-NH2 donors. Structural and kinetic studies of multi-specific enzymes show that active sites can accommodate related aldehyde/oxo substrates with differential inhibition profiles.
Hydride transfer to NAD+ or NADP+
In simple terms: The enzyme removes a hydride from the substrate and hands it to NAD+ or NADP+, turning it into NADH or NADPH.
The catalytic step involves transfer of a hydride equivalent from the aldehyde or oxo donor to the nicotinamide ring of NAD+ or NADP+, reducing it to NADH or NADPH. This reaction is stereospecific and depends on the enzyme's ability to stabilize the transition state. The choice between NAD+ and NADP+ is determined by the enzyme's active-site architecture and is a key annotation criterion for GO:0016620.
Cofactor supply and NAD(P)(H) homeostasis
In simple terms: The reaction needs a steady supply of NAD+ or NADP+, which is maintained by other enzymes like NAD kinase.
NAD kinase phosphorylates NAD+ to generate NADP+, the precursor of NADPH, which is the reduced cofactor required by many NADP-dependent oxidoreductases. Human NAD kinase is regulated at the structural level, and its cryo-EM structure reveals mechanisms of regulation. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, linking cofactor supply to one-carbon metabolism. In plants, CCR4C is a chloroplast-localized NADP(H) phosphatase that regulates NAD(P)(H) balance, demonstrating conservation of cofactor control.
Physiological context: proline biosynthesis and polyamine catabolism
In simple terms: These redox reactions are part of larger pathways, such as making proline or breaking down polyamines.
Mitochondrial NADP(H) generation is essential for proline biosynthesis, a pathway that depends on NADP-dependent oxidoreductase chemistry. Spermine oxidase, which oxidizes spermine to produce hydrogen peroxide and acrolein, is an example of an aldehyde/oxo redox enzyme linked to gastric carcinogenesis. Polyamine metabolism is also altered in renal failure, where polyamine catabolism contributes to pathology.
Regulation by substrate availability and inhibitors
In simple terms: The speed of these reactions can be tuned by how much substrate is available and by molecules that block the enzyme.
Intra-site differential inhibition of multi-specific enzymes shows that active sites can be selectively inhibited, providing a mechanism for fine-tuning aldehyde/oxo oxidoreductase activity. Cofactor availability, especially NADP(H) levels controlled by NAD kinase and NADP(H) phosphatases, further regulates flux through these reactions. In disease contexts, altered expression of enzymes such as spermine oxidase can change flux and produce toxic aldehydes like acrolein.
Key Genes Involved in GO:0016620 oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor
The following genes encode enzymes or regulators directly relevant to GO:0016620, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NADK | NAD kinase generates NADP+ from NAD+, supplying cofactor for NADP-dependent oxidoreductases | Cryo-EM structure and regulation; conditional essentiality in folate-dependent nucleotide synthesis |
| SMOX | Spermine oxidase oxidizes spermine, producing hydrogen peroxide and acrolein | Promotes Helicobacter pylori-mediated gastric carcinogenesis |
| CCR4C | Chloroplast-localized NADP(H) phosphatase regulating NAD(P)(H) balance | Plant model for NAD(P)(H) homeostasis |
| PRODH | Proline dehydrogenase involved in proline catabolism, linked to mitochondrial NADP(H) generation | Proline biosynthesis and cancer metabolism |
| PYCR1 | Pyrroline-5-carboxylate reductase, NADP-dependent enzyme in proline biosynthesis | Mitochondrial NADP(H) dependence |
| ALDH1A1 | Aldehyde dehydrogenase, NAD-dependent oxidation of aldehydes | Cancer stem cell and drug resistance studies |
| ALDH2 | Mitochondrial aldehyde dehydrogenase, NAD-dependent | Alcohol metabolism and cardiovascular disease |
| ALDH3A1 | Aldehyde dehydrogenase, NADP-dependent | Corneal and cancer biology |
| AKR1A1 | Aldo-keto reductase, NADP-dependent | Detoxification and metabolic studies |
| AKR1B1 | Aldo-keto reductase, NADP-dependent | Diabetic complications and cancer |
| AKR1C1 | Aldo-keto reductase, NADP-dependent | Steroid metabolism and cancer |
| GAPDH | Glyceraldehyde-3-phosphate dehydrogenase, NAD-dependent | Glycolysis and redox regulation |
| HSD17B10 | Hydroxysteroid dehydrogenase, NAD-dependent | Neurodegeneration and steroid metabolism |
| DCXR | Dicarbonyl/L-xylulose reductase, NADP-dependent | Metabolic and detoxification studies |
| NADSYN1 | NAD synthetase, NAD biosynthesis | NAD pool regulation |
| NMNAT1 | Nicotinamide mononucleotide adenylyltransferase, NAD biosynthesis | NAD homeostasis and neuroprotection |
| NAMPT | Nicotinamide phosphoribosyltransferase, NAD salvage | Metabolic disease and cancer |
How Is oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor Regulated?
The activity of enzymes in GO:0016620 is regulated at multiple levels. Cofactor availability is a primary control point: NAD kinase (NADK) generates NADP+, and its regulation directly affects NADP-dependent oxidoreductases. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, linking cofactor supply to one-carbon metabolism. In plants, CCR4C regulates NAD(P)(H) balance by dephosphorylating NADP(H). Substrate availability and enzyme expression also modulate flux; for example, spermine oxidase expression influences acrolein production in gastric carcinogenesis. Additionally, multi-specific enzymes can be differentially inhibited at their active sites, providing another layer of regulation.
oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SMOX | Gastric carcinogenesis via acrolein production | SMOX knockout gastric organoids or cell lines |
| NADK | Folate-dependent nucleotide synthesis; metabolic regulation | NADK knockout or point-mutation cell lines |
| PYCR1 | Proline biosynthesis in cancer | PYCR1 knockout cancer cells |
| CCR4C | NAD(P)(H) balance in plants | CCR4C knockout Arabidopsis |
| ALDH2 | Alcohol metabolism and cardiovascular disease | ALDH2 point-mutation knock-in mice or cells |
Cancer
Spermine oxidase (SMOX) promotes Helicobacter pylori-mediated gastric carcinogenesis through production of acrolein, a toxic aldehyde generated during polyamine oxidation. Mitochondrial NADP(H) generation is essential for proline biosynthesis, which supports cancer cell proliferation. Cytosolic NADK is conditionally essential for folate-dependent nucleotide synthesis, a pathway required for cancer cell growth.
Metabolic and renal disorders
Polyamine metabolism is altered in renal failure, where polyamine catabolism contributes to pathology. NAD kinase and NAD(P)(H) balance are central to metabolic regulation, and their dysfunction can affect nucleotide synthesis and redox homeostasis.
Neurodegeneration and oxidative stress
Aldehyde/oxo oxidoreductases such as aldehyde dehydrogenases and aldo-keto reductases detoxify reactive aldehydes produced during oxidative stress. While specific disease links are beyond the cited literature, the general role of these enzymes in maintaining redox balance is supported by their cofactor dependence on NAD(P).
From oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate oxidoreductase affect NAD(P)H levels? | CRISPR knockout cell line |
| Does a specific catalytic residue mediate hydride transfer? | Point-mutation knock-in |
| Does tagging the endogenous enzyme alter localization? | Tagged knock-in |
| Does overexpression of NADK increase NADP(H) and proline synthesis? | Overexpression cell line |
| Does SMOX knockout reduce acrolein and gastric carcinogenesis? | SMOX knockout organoids |
| Does NADK loss impair folate-dependent nucleotide synthesis? | NADK knockout cells |
How to Study the oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Transcript levels of oxidoreductase genes | Expression profiling after knockout or treatment |
| CRISPR knockout screening | Gene essentiality and fitness | Identifying NAD(P)-related metabolic dependencies |
| LC-MS metabolomics | NAD(P)(H), proline, polyamines | Quantifying pathway flux |
| Cryo-EM | Protein structure and cofactor binding | Mechanistic studies of NADK |
| Enzyme kinetics | Catalytic rate and inhibition | Characterizing multi-specific enzymes |
| Redox biosensors | Live-cell NAD(P)H levels | Monitoring metabolic state |
| Western blot | Protein expression and modification | Validating knockout or overexpression |
| Immunofluorescence | Subcellular localization | Determining organelle-specific function |
Genomic and transcriptomic profiling
RNA-seq and CRISPR screening can identify genes required for NAD(P)(H) homeostasis and aldehyde/oxo metabolism. Functional annotation with GO:0016620 helps prioritize candidate oxidoreductases.
Metabolomics and cofactor measurement
LC-MS-based metabolomics quantifies NAD+, NADP+, NADH, and NADPH, providing direct readouts of GO:0016620 activity. Proline and polyamine levels can be measured to assess pathway flux.
Structural and biochemical assays
Cryo-EM and X-ray crystallography reveal active-site architecture and cofactor binding. Enzyme kinetics with NAD+ or NADP+ as acceptor measure catalytic efficiency and inhibition.
Imaging and redox sensors
Genetically encoded NAD(P)H sensors and fluorescent probes can monitor redox state in live cells, linking enzyme activity to cellular physiology.
How CRISPR Can Be Used to Study GO:0016620 oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor
Knockout
CRISPR knockout of genes encoding GO:0016620 enzymes or their regulators (e.g., NADK, SMOX) can reveal loss-of-function phenotypes in metabolism, proliferation, and redox balance. Knockout cell lines are useful for measuring changes in NAD(P)(H) and pathway flux.
Point Mutation
Point-mutation knock-in can test the role of specific catalytic residues in hydride transfer or cofactor specificity. For example, mutating NADK active-site residues can alter NADP+ production.
Knock-in
Tagged knock-in of endogenous oxidoreductase genes enables localization and interaction studies without overexpression artifacts. This is valuable for determining organelle-specific functions such as chloroplast NADP(H) regulation.
Overexpression
Overexpression of NADK or other oxidoreductases can increase NADP(H) pools and drive biosynthetic pathways such as proline synthesis. Overexpression models help establish sufficiency in pathway activation.
How EDITGENE Supports oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor Research
Researchers studying oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor-related genes often need to determine whether a candidate gene is causally involved in redox metabolism, cofactor homeostasis, or disease phenotypes. EDITGENE provides publication-ready CRISPR models and screening services to accelerate this causal validation.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor research.
Frequently Asked Questions About oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor
What is GO:0016620?
GO:0016620 is a Gene Ontology molecular function term for oxidoreductase activity acting on aldehyde or oxo group donors with NAD or NADP as the electron acceptor.
What genes are involved in oxidoreductase activity, acting on the aldehyde or oxo group of donors, NAD or NADP as acceptor?
Genes include NADK, SMOX, PYCR1, ALDH family members, AKR family members, and others encoding NAD(P)-dependent oxidoreductases.
What does NAD kinase do in this context?
NAD kinase generates NADP+ from NAD+, supplying the cofactor required by NADP-dependent oxidoreductases.
How is GO:0016620 related to cancer?
Spermine oxidase produces acrolein and promotes gastric carcinogenesis, and NADP(H)-dependent proline biosynthesis supports cancer growth.
What experimental models are used to study GO:0016620?
CRISPR knockout, point-mutation, knock-in, overexpression cell lines, and metabolomics are commonly used.
What is the role of NADP(H) in these reactions?
NADP(H) is the reduced cofactor produced when NADP+ accepts electrons from aldehyde or oxo donors.
Which diseases are linked to aldehyde/oxo oxidoreductases?
Cancer, metabolic disorders, and renal failure have been linked to altered activity of these enzymes.
How can I study NAD(P)(H) balance?
LC-MS metabolomics and genetically encoded redox sensors can measure NAD(P)(H) levels.
What is the difference between NAD+ and NADP+ in these reactions?
Both can act as electron acceptors, but NADP+ is typically used in reductive biosynthesis while NAD+ is used in catabolism.
Can CRISPR screens identify new regulators of GO:0016620?
Yes, genome-wide CRISPR screens can identify genes required for NAD(P)(H) homeostasis and oxidoreductase function.
Conclusion
GO:0016620 defines a fundamental class of redox enzymes that couple aldehyde or ketone oxidation to NAD(P)+ reduction, impacting biosynthesis, detoxification, and disease. Key genes such as NADK, SMOX, and PYCR1 illustrate the diverse physiological roles of this activity. Understanding these enzymes requires integrated approaches including CRISPR models, metabolomics, and structural biology. EDITGENE offers comprehensive services to support causal studies of GO:0016620-related genes.
References
- 1. Zhu J et al.. 2021. Mitochondrial NADP(H) generation is essential for proline biosynthesis.. Science 372(6545):968-972 PMID: 33888598
- 2. McGuinness ET et al.. 1985. NAD+ kinase--a review.. Int J Biochem 17(1):1-11 PMID: 2987053
- 3. McNamara KM et al.. 2025. Spermine oxidase promotes Helicobacter pylori-mediated gastric carcinogenesis through acrolein production.. Oncogene 44(5):296-306 PMID: 39523394
- 4. Praharaj PP et al.. 2025. Cryo-EM structure and regulation of human NAD kinase.. Sci Adv 11(4):eads2664 PMID: 39854463
- 5. Cappiello M et al.. 2020. Intra-site differential inhibition of multi-specific enzymes.. J Enzyme Inhib Med Chem 35(1):840-846 PMID: 32208768
- 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. Igarashi K et al.. 2006. Polyamines in renal failure.. Amino Acids 31(4):477-83 PMID: 16554974
