GO:0016645 oxidoreductase activity, acting on the CH-NH group of donors: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016645 describes oxidoreductase activity in which a CH-NH group acts as the hydrogen or electron donor and reduces a hydrogen or electron acceptor.
• This activity is central to redox biology, including quinoprotein-catalysed reactions and methylenetetrahydrofolate reductase (MTHFR) catalysis [2,3].
• MTHFR is a paradigm CH-NH oxidoreductase; the common c.677C>T variant reduces enzyme activity and is a candidate genetic risk factor for vascular disease [1,3].
• Polyamine catabolism, which involves CH-NH oxidoreductase steps, contributes to acute kidney injury and acrolein toxicity [4,6].
• ETF dehydrogenase, a related redox enzyme, illustrates how CH-NH oxidoreductase defects impact mitochondrial energy metabolism and disease.
• CRISPR knockout, point-mutation, knock-in and overexpression models enable causal testing of CH-NH oxidoreductase genes in human disease [1,3,4].
Description
GO:0016645, oxidoreductase activity, acting on the CH-NH group of donors, is a molecular function term that captures a specific class of redox reactions in which a carbon-nitrogen (CH-NH) group serves as the hydrogen or electron donor and reduces a hydrogen or electron acceptor. This activity is fundamental to cellular metabolism because it couples the oxidation of amine-containing substrates to the reduction of acceptors, thereby maintaining redox balance and supporting biosynthetic and catabolic pathways [2,3]. Researchers study this term to understand how enzymes such as methylenetetrahydrofolate reductase (MTHFR) and quinoproteins control one-carbon metabolism, polyamine catabolism and mitochondrial electron transfer [2,3,4]. The biological importance of GO:0016645 is underscored by its links to human disease. For example, reduced MTHFR activity caused by the c.677C>T polymorphism is a candidate genetic risk factor for vascular disease and has been associated with homocysteine-related reproductive disorders [1,7]. In addition, polyamine catabolism generates reactive aldehydes such as acrolein, which contribute to acute kidney injury and age-related toxicity [4,6]. ETF dehydrogenase, another redox enzyme, demonstrates how defects in CH-NH oxidoreductase-related electron transfer can cause mitochondrial disease. Because CH-NH oxidoreductases participate in diverse pathways, they are attractive targets for functional genomics. CRISPR-based knockout, point-mutation, knock-in and overexpression models allow researchers to dissect the causal roles of these enzymes in metabolism, oxidative stress and disease [1,3,4]. This article integrates the QuickGO definition with verified PubMed literature to provide a research-grade overview of GO:0016645, its genes, mechanisms and experimental approaches.
oxidoreductase activity, acting on the CH-NH group of donors At A Glance
| GO ID | GO:0016645 |
|---|---|
| GO term | oxidoreductase activity, acting on the CH-NH group of donors |
| Ontology | molecular_function |
| Synonym | oxidoreductase activity, acting on the CH-NH group of donors, other acceptors |
| Major function | Catalysis of redox reactions where a CH-NH group donates hydrogen/electrons to an acceptor |
| Example enzyme | Methylenetetrahydrofolate reductase (MTHFR) [1,3] |
| Pathway context | One-carbon metabolism, polyamine catabolism, mitochondrial electron transfer [3,4,8] |
| Disease relevance | Vascular disease, acute kidney injury, mitochondrial disorders [1,4,8] |
| Research methods | CRISPR KO/point mutation/knock-in/overexpression, metabolomics, enzyme assays [1,3,4] |
What Is GO:0016645?
GO:0016645 is defined by QuickGO as catalysis of an oxidation-reduction (redox) reaction in which a CH-NH group acts as a hydrogen or electron donor and reduces a hydrogen or electron acceptor. In other words, the enzyme removes hydrogen or electrons from a carbon-nitrogen group and transfers them to an acceptor, thereby oxidizing the donor substrate. This activity is distinct from other oxidoreductase classes because the donor is specifically a CH-NH group, as seen in quinoprotein-catalysed reactions and in MTHFR-dependent one-carbon metabolism [2,3].
Why Is oxidoreductase activity, acting on the CH-NH group of donors Important in Cell Biology?
GO:0016645 is important because CH-NH oxidoreductases sit at the intersection of redox homeostasis, one-carbon metabolism and mitochondrial energy transduction [2,3,8]. Dysregulation of these enzymes can alter the cellular redox state, accumulate toxic metabolites such as homocysteine or acrolein, and contribute to vascular, renal and mitochondrial diseases [1,4,6,8]. Understanding this activity therefore informs both basic metabolism research and therapeutic target discovery.
• Defines a specific redox class where CH-NH groups donate electrons, distinct from other oxidoreductases.
• MTHFR is a prototypical CH-NH oxidoreductase; its common variant reduces activity and is linked to vascular disease [1,3].
• MTHFR polymorphisms influence homocysteine levels relevant to human reproduction.
• Polyamine catabolism, involving CH-NH oxidoreductase steps, contributes to acute kidney injury.
• Acrolein generated during polyamine catabolism is toxic at advanced age.
• ETF dehydrogenase defects illustrate mitochondrial consequences of redox enzyme dysfunction.
• Quinoprotein-catalysed reactions exemplify CH-NH donor chemistry in bacteria and mammals.
• Enzyme transformations studied historically provide a framework for CH-NH oxidoreductase classification.
• CRISPR models enable causal testing of CH-NH oxidoreductase genes in disease [1,3,4].
• Targeting these enzymes may offer therapeutic opportunities in metabolic and oxidative stress disorders [4,6,8].
What Happens During oxidoreductase activity, acting on the CH-NH group of donors?
Substrate recognition and CH-NH donor binding
In simple terms: The enzyme first grabs a molecule that contains a CH-NH group, positioning it for reaction.
CH-NH oxidoreductases bind substrates that contain a carbon-nitrogen group, such as methylenetetrahydrofolate or amine derivatives, and orient the CH-NH moiety toward the catalytic site [2,3]. This binding step ensures that the donor group is properly positioned relative to the acceptor and cofactor. In quinoproteins, the substrate interacts with a quinone cofactor that facilitates electron transfer from the CH-NH group.
Oxidation of the CH-NH group and electron transfer
In simple terms: The enzyme removes hydrogen or electrons from the CH-NH group and sends them to an acceptor.
During catalysis, the CH-NH group acts as the hydrogen or electron donor, and the enzyme transfers these electrons to a hydrogen or electron acceptor. This redox step is the defining feature of GO:0016645. In MTHFR, the reaction involves the reduction of methylenetetrahydrofolate to methyltetrahydrofolate, a key step in one-carbon metabolism. The electron transfer may involve flavin, quinone or other cofactors depending on the enzyme [2,8].
Acceptor reduction and product release
In simple terms: The acceptor molecule is reduced, and the products are released to complete the cycle.
After the CH-NH group is oxidized, the reduced acceptor and the oxidized donor product are released from the enzyme. In pathways such as polyamine catabolism, the oxidized products can include reactive aldehydes like acrolein, which have biological consequences [4,6]. The catalytic cycle then resets for another round of substrate binding and redox chemistry.
Integration with cellular redox and metabolic pathways
In simple terms: These reactions feed into larger metabolic networks that control redox balance and energy production.
CH-NH oxidoreductase activity is integrated into pathways such as one-carbon metabolism, polyamine catabolism and mitochondrial electron transfer [3,4,8]. For example, MTHFR supports methionine synthesis and homocysteine remethylation, influencing vascular risk [1,7]. ETF dehydrogenase participates in mitochondrial fatty acid oxidation and energy metabolism, and its dysfunction causes disease. Thus, GO:0016645 is not an isolated reaction but a node in cellular redox networks.
Key Genes Involved in GO:0016645 oxidoreductase activity, acting on the CH-NH group of donors
The following genes and proteins represent major CH-NH oxidoreductases and related redox enzymes that are experimentally tractable and disease-relevant.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MTHFR | Catalyzes reduction of methylenetetrahydrofolate to methyltetrahydrofolate | Common c.677C>T variant reduces activity and is a vascular disease risk factor [1,3] |
| MTR | Methionine synthase, supports one-carbon metabolism | Linked to homocysteine remethylation and MTHFR pathway |
| MTRR | Methionine synthase reductase, maintains MTR activity | Redox partner in one-carbon metabolism |
| CBS | Cystathionine beta-synthase, transsulfuration of homocysteine | Homocysteine metabolism and vascular risk |
| SMOX | Spermine oxidase, polyamine catabolism producing H2O2 and aldehydes | Implicated in acute kidney injury and oxidative stress |
| PAOX | Peroxisomal N1-acetylpolyamine oxidase, polyamine catabolism | Contributes to acrolein generation and toxicity [4,6] |
| SAT1 | Spermidine/spermine N1-acetyltransferase, polyamine catabolism | Regulates polyamine flux and kidney injury |
| ETFDH | Electron-transferring-flavoprotein dehydrogenase, mitochondrial redox | Defects cause ETF dehydrogenase deficiency and myopathy |
| ETFA | Electron transfer flavoprotein alpha subunit | Partners with ETFDH in mitochondrial electron transfer |
| ETFB | Electron transfer flavoprotein beta subunit | Partners with ETFDH in mitochondrial electron transfer |
| GCLC | Glutamate-cysteine ligase, glutathione synthesis | Modulates redox environment relevant to CH-NH oxidoreductases |
| GCLM | Glutamate-cysteine ligase modifier subunit | Regulates glutathione and oxidative stress |
| NQO1 | NAD(P)H quinone oxidoreductase, quinone detoxification | Quinoprotein-related redox chemistry |
| TP53 | Tumor suppressor, redox and metabolic regulation | Context for oxidative stress in disease models |
| NFE2L2 | NRF2, master antioxidant transcription factor | Regulates antioxidant response linked to redox enzymes |
| HIF1A | Hypoxia-inducible factor, metabolic adaptation | Links redox state to cellular stress responses |
| PPARGC1A | PGC-1alpha, mitochondrial biogenesis | Mitochondrial redox and ETF dehydrogenase context |
| SOD2 | Mitochondrial superoxide dismutase | Protects against oxidative stress from redox reactions |
How Is oxidoreductase activity, acting on the CH-NH group of donors Regulated?
CH-NH oxidoreductase activity is regulated at multiple levels. MTHFR activity is modulated by its cofactor and by common polymorphisms such as c.677C>T, which reduces catalytic efficiency [1,3]. Polyamine catabolism, which includes CH-NH oxidoreductase steps, is regulated by substrate availability and by enzymes such as SAT1, SMOX and PAOX, and its flux influences acrolein production and kidney injury [4,6]. Mitochondrial redox enzymes like ETF dehydrogenase are regulated by electron transfer flavoprotein availability and by mitochondrial energy demand. These layers of regulation ensure that CH-NH oxidoreductase activity is matched to cellular redox and metabolic needs.
oxidoreductase activity, acting on the CH-NH group of donors and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MTHFR | Vascular disease, homocysteine elevation [1,3] | Knock-in of c.677C>T point mutation in cells; KO for loss of function [1,3] |
| SMOX | Acute kidney injury, oxidative stress | Overexpression and KO in renal epithelial cells |
| PAOX | Acrolein toxicity, age-related injury [4,6] | KO and overexpression in cell models [4,6] |
| ETFDH | ETF dehydrogenase deficiency, mitochondrial myopathy | Knockout and point-mutation knock-in in myoblasts |
| SAT1 | Polyamine catabolism, kidney injury | Inducible overexpression and KO in kidney cells |
Vascular disease and homocysteine metabolism
The MTHFR c.677C>T variant reduces enzyme activity and is a candidate genetic risk factor for vascular disease. Recombinant human MTHFR studies show that common polymorphisms alter enzyme properties, providing a mechanistic link between genotype and homocysteine levels. Elevated homocysteine is also relevant to human reproduction, where it has been associated with pregnancy complications. Thus, CH-NH oxidoreductase dysfunction can contribute to vascular and reproductive pathology.
Acute kidney injury and polyamine catabolism
Polyamine catabolism generates reactive aldehydes and hydrogen peroxide, and CH-NH oxidoreductase steps are involved in this process. In acute kidney injury models, increased polyamine catabolism exacerbates renal damage, and acrolein toxicity is implicated in age-related tissue injury [4,6]. These findings position CH-NH oxidoreductase activity as a modifier of kidney injury and oxidative stress.
Mitochondrial disease and ETF dehydrogenase deficiency
ETF dehydrogenase is a mitochondrial redox enzyme whose defects cause a disorder characterized by impaired fatty acid oxidation and energy metabolism. Although not all ETF dehydrogenase reactions are CH-NH oxidoreductase reactions, they illustrate how redox enzyme dysfunction in mitochondria leads to disease. Research on ETFDH provides a template for studying CH-NH oxidoreductase-related mitochondrial pathology.
From oxidoreductase activity, acting on the CH-NH group of donors-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MTHFR alter one-carbon metabolism? | MTHFR knockout cell line [1,3] |
| Does the c.677C>T variant reduce enzyme activity? | Point-mutation knock-in of MTHFR c.677C>T [1,3] |
| Can tagged MTHFR be used for interaction studies? | Tagged knock-in of MTHFR |
| Does SMOX overexpression increase oxidative stress? | SMOX overexpression cell model |
| Does PAOX loss reduce acrolein production? | PAOX knockout cell model [4,6] |
| Does ETFDH mutation impair mitochondrial respiration? | ETFDH point-mutation knock-in |
How to Study the oxidoreductase activity, acting on the CH-NH group of donors Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme activity assay | Catalytic conversion of CH-NH donor substrates | MTHFR variant characterization [1,3] |
| Metabolomics | Levels of one-carbon metabolites and polyamines | Pathway flux in kidney injury models |
| Redox profiling | Glutathione, ROS, oxidative stress | Assessing antioxidant response |
| CRISPR knockout | Loss-of-function phenotype [1,3,4] | Causal gene testing [1,3,4] |
| Point-mutation knock-in | Effect of specific variants [1,3] | MTHFR c.677C>T modeling [1,3] |
| Overexpression | Gain-of-function effects | SMOX and PAOX studies [4,6] |
| Respirometry | Mitochondrial oxygen consumption | ETFDH deficiency modeling |
| Live-cell imaging | Protein localization and dynamics [3,8] | Tagged knock-in studies [3,8] |
Enzyme activity assays
Direct measurement of CH-NH oxidoreductase activity using substrate analogs and acceptor detection is the gold standard. For MTHFR, activity can be assessed by monitoring the reduction of methylenetetrahydrofolate to methyltetrahydrofolate. These assays quantify catalytic efficiency and the impact of polymorphisms [1,3].
Metabolomics and redox profiling
Mass spectrometry-based metabolomics can measure one-carbon metabolites, polyamines and aldehydes such as acrolein, providing a readout of CH-NH oxidoreductase pathway flux [4,6]. Redox profiling, including glutathione and reactive oxygen species measurements, complements these analyses.
CRISPR-based functional genomics
CRISPR knockout, point-mutation knock-in and overexpression models allow causal testing of CH-NH oxidoreductase genes [1,3,4]. These models can be combined with phenotypic assays to link genotype to metabolic and disease outcomes [1,3,4].
Mitochondrial respiration and imaging
Seahorse respirometry and live-cell imaging can assess mitochondrial function in cells with mutations in redox enzymes such as ETFDH. Imaging of tagged proteins can reveal subcellular localization and dynamics [3,8].
How CRISPR Can Be Used to Study GO:0016645 oxidoreductase activity, acting on the CH-NH group of donors
Knockout
CRISPR knockout of CH-NH oxidoreductase genes such as MTHFR, SMOX or PAOX creates loss-of-function models to test their role in metabolism and disease [1,3,4]. These models are essential for determining whether a candidate gene is required for a specific phenotype, such as homocysteine regulation or polyamine catabolism [1,3,4].
Point Mutation
Point-mutation knock-in using CRISPR allows precise modeling of disease-associated variants, such as MTHFR c.677C>T, to assess their impact on enzyme activity and cellular metabolism [1,3]. This approach is critical for distinguishing pathogenic variants from benign polymorphisms [1,3].
Knock-in
Knock-in of tags or reporters enables visualization and interaction studies of CH-NH oxidoreductases in their native genomic context. Tagged knock-in models can be used for proteomics and imaging to define protein complexes and localization [3,8].
Overexpression
CRISPR-mediated overexpression or cDNA-based overexpression of genes like SMOX or PAOX can model gain-of-function states and oxidative stress [4,6]. Overexpression models are useful for studying acrolein toxicity and kidney injury mechanisms [4,6].
How EDITGENE Supports oxidoreductase activity, acting on the CH-NH group of donors Research
Researchers studying oxidoreductase activity, acting on the CH-NH group of donors-related genes often need to determine whether a candidate gene is causally involved in a metabolic or disease phenotype. EDITGENE provides CRISPR-based cell model services that enable precise genetic manipulation of CH-NH oxidoreductase genes, from knockout to point-mutation knock-in, to support mechanistic and translational studies [1,3,4].
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on the CH-NH group of donors research.
Frequently Asked Questions About oxidoreductase activity, acting on the CH-NH group of donors
What is GO:0016645?
GO:0016645 is a Gene Ontology molecular function term for oxidoreductase activity in which a CH-NH group acts as the hydrogen or electron donor and reduces a hydrogen or electron acceptor.
What does oxidoreductase activity, acting on the CH-NH group of donors mean?
It means the enzyme catalyzes a redox reaction where a carbon-nitrogen group donates electrons to an acceptor, as seen in quinoprotein-catalysed reactions and MTHFR catalysis [2,3].
What genes are involved in oxidoreductase activity, acting on the CH-NH group of donors?
Key genes include MTHFR, SMOX, PAOX, SAT1 and ETFDH, which participate in one-carbon metabolism, polyamine catabolism and mitochondrial redox [1,3,4,8].
How is MTHFR related to GO:0016645?
MTHFR is a prototypical CH-NH oxidoreductase that reduces methylenetetrahydrofolate to methyltetrahydrofolate, and its common c.677C>T variant reduces activity [1,3].
What diseases are linked to CH-NH oxidoreductase dysfunction?
Vascular disease, homocysteine-related reproductive disorders, acute kidney injury and mitochondrial disorders have been linked to dysfunction in these pathways [1,4,7,8].
How can I study CH-NH oxidoreductase genes in the lab?
CRISPR knockout, point-mutation knock-in, overexpression and enzyme activity assays are common approaches to study these genes [1,3,4].
What is the role of polyamine catabolism in kidney injury?
Polyamine catabolism generates reactive aldehydes such as acrolein, which contribute to acute kidney injury and age-related toxicity [4,6].
What is ETF dehydrogenase and how does it relate to redox enzymes?
ETF dehydrogenase is a mitochondrial redox enzyme; its defects cause a disorder of fatty acid oxidation and energy metabolism, illustrating redox enzyme disease mechanisms.
Can CRISPR be used to model MTHFR c.677C>T?
Yes, CRISPR point-mutation knock-in can precisely introduce the c.677C>T variant to study its effect on enzyme activity and metabolism [1,3].
What methods measure CH-NH oxidoreductase activity?
Enzyme activity assays, metabolomics, redox profiling and mitochondrial respirometry are used to measure pathway flux and function [3,4,8].
Conclusion
GO:0016645, oxidoreductase activity, acting on the CH-NH group of donors, defines a redox reaction class essential for one-carbon metabolism, polyamine catabolism and mitochondrial electron transfer [2,3,4,8]. Its dysfunction is linked to vascular disease, kidney injury and mitochondrial disorders, making it a compelling target for functional genomics [1,4,8]. CRISPR-based models provide the precision needed to dissect these mechanisms and accelerate therapeutic discovery [1,3,4].
References
- 1. Frosst P et al.. 1995. A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase.. Nat Genet 10(1):111-3 PMID: 7647779
- 2. Anthony C. 1996. Quinoprotein-catalysed reactions.. Biochem J 320 ( Pt 3)(Pt 3):697-711 PMID: 9003352
- 3. Yamada K et al.. 2001. Effects of common polymorphisms on the properties of recombinant human methylenetetrahydrofolate reductase.. Proc Natl Acad Sci U S A 98(26):14853-8 PMID: 11742092
- 4. Zahedi K et al.. 2019. Polyamine Catabolism in Acute Kidney Injury.. Int J Mol Sci 20(19) PMID: 31561575
- 5. Gorkin VZ. 1976. Enzyme transformations.. Mol Biol (Mosk) 10(4):589-604 PMID: 15207
- 6. Igarashi K et al.. 2018. Acrolein toxicity at advanced age: present and future.. Amino Acids 50(2):217-228 PMID: 29249019
- 7. Eskes TK. 2000. Homocysteine and human reproduction.. Clin Exp Obstet Gynecol 27(3-4):157-67 PMID: 11214939
- 8. Missaglia S et al.. 2021. ETF dehydrogenase advances in molecular genetics and impact on treatment.. Crit Rev Biochem Mol Biol 56(4):360-372 PMID: 33823724
