GO:0016661 oxidoreductase activity, acting on other nitrogenous compounds as donors: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016661 describes a molecular function: catalysis of a redox reaction in which a nitrogenous group other than NH or NH2 acts as the electron/hydrogen donor.
• The term is defined by donor chemistry rather than by a single enzyme family, so it captures diverse enzymes that oxidize nitrogen-containing substrates.
• Representative enzymes include spermine oxidase, which oxidizes polyamines such as spermine and is studied with pentamine substrate analogues.
• Nitrogen-metabolizing redox steps are central to bacterial nitrogen metabolism, as shown by pleiotropic nit mutants of Salmonella typhimurium.
• The activity is relevant to biodegradation and environmental nitrogen cycling, and biodegrading enzymes are catalogued in dedicated databases.
• Redox reactions on nitrogenous donors intersect with cellular redox and gasotransmitter signaling, including H2S and NO effects on NADP-dependent isocitrate dehydrogenase.
Description
GO:0016661, oxidoreductase activity, acting on other nitrogenous compounds as donors, is a molecular function term in the Gene Ontology that groups enzymes performing oxidation-reduction reactions where the electron-donating species is a nitrogenous group other than NH or NH2. Because the classification is based on the chemistry of the donor rather than on a shared protein fold, the term spans multiple enzyme families and biological contexts, from polyamine oxidation to bacterial nitrogen metabolism. Researchers annotate proteins to this term when experimental evidence shows that the protein catalyzes a redox reaction consuming a nitrogenous donor and reducing a hydrogen or electron acceptor. The term is therefore a useful entry point for understanding how cells and microbes transform nitrogen-containing molecules, a process that affects signaling, nutrient handling, and environmental nitrogen flux. In practice, GO:0016661 helps connect sequence and structural data to biochemical function, guiding hypothesis-driven experiments such as substrate profiling, inhibitor testing, and genetic perturbation.
oxidoreductase activity, acting on other nitrogenous compounds as donors At A Glance
| GO ID | GO:0016661 |
|---|---|
| GO term | oxidoreductase activity, acting on other nitrogenous compounds as donors |
| Ontology | molecular_function |
| Synonym | oxidoreductase activity, acting on other nitrogenous compounds as donors, other acceptors |
| Definition | Catalysis of an oxidation-reduction (redox) reaction in which a nitrogenous group, excluding NH and NH2 groups, acts as a hydrogen or electron donor and reduces a hydrogen or electron acceptor. |
| Reaction type | Oxidation-reduction (redox) |
| Donor class | Nitrogenous group other than NH or NH2 |
| Acceptor | Hydrogen or electron acceptor |
| Representative enzyme example | Spermine oxidase acting on polyamine substrates |
| Related biological context | Nitrogen metabolism and biodegradation |
What Is GO:0016661?
In plain terms, GO:0016661 is the activity of an enzyme that removes electrons from a nitrogen-containing molecule (but not from an NH or NH2 group) and passes them to an acceptor. The QuickGO definition states that it catalyzes an oxidation-reduction reaction in which a nitrogenous group, excluding NH and NH2 groups, acts as a hydrogen or electron donor and reduces a hydrogen or electron acceptor. The synonym oxidoreductase activity, acting on other nitrogenous compounds as donors, other acceptors reflects the same chemistry with a different acceptor. This is a molecular_function term, so it describes what a protein does at the reaction level rather than where it acts or which pathway it belongs to.
Why Is oxidoreductase activity, acting on other nitrogenous compounds as donors Important in Cell Biology?
GO:0016661 matters because redox transformations of nitrogenous compounds sit at the intersection of cellular metabolism, signaling, and environmental nutrient cycling. Enzymes annotated to this term can control the levels of bioactive nitrogen-containing molecules, and their chemistry is exploited in drug discovery and in understanding microbial nitrogen handling. Because the term is chemistry-defined, it also provides a framework for comparing mechanistically diverse enzymes and for predicting the behavior of uncharacterized proteins that act on nitrogenous donors.
• Defines a distinct redox chemistry class that is not captured by NH/NH2 donor terms, improving functional annotation precision.
• Includes polyamine-oxidizing enzymes such as spermine oxidase, which are studied with substrate analogues like pentamines.
• Connects to bacterial nitrogen metabolism through pleiotropic nit mutants that affect multiple nitrogen pathways.
• Supports biodegradation research, where nitrogen-transforming enzymes are catalogued and compared.
• Intersects with redox signaling, since H2S and NO can modulate NADP-dependent isocitrate dehydrogenase activity.
• Provides a functional handle for inhibitor discovery, as illustrated by DHODH inhibitor isostere studies in redox-related enzyme targeting.
• Helps interpret environmental metagenomic and biogeochemical data on nitrogenous compound turnover.
• Offers a basis for mechanistic modeling of metal-containing redox catalysts relevant to nitrogen donor chemistry.
• Guides substrate-specificity experiments using synthetic analogues of natural nitrogenous donors.
• Enables comparative analysis of enzymes that reduce or oxidize sterol and nitrogen-containing intermediates.
Molecular Function of oxidoreductase activity, acting on other nitrogenous compounds as donors
Donor recognition and substrate binding
In simple terms: The enzyme first grabs the nitrogen-containing molecule that will give up electrons.
Enzymes annotated to GO:0016661 bind a nitrogenous donor that is not an NH or NH2 group, positioning it for oxidation. Substrate recognition can be probed with structural analogues; for example, pentamines have been used as substrates for human spermine oxidase, showing that polyamine chain length and charge influence turnover. This step determines specificity and is often the first target of inhibitor design.
Electron transfer to the acceptor
In simple terms: Electrons stripped from the nitrogenous donor are handed to an acceptor molecule.
The defining chemistry of GO:0016661 is reduction of a hydrogen or electron acceptor by a nitrogenous donor. The acceptor can vary, which is why the synonym specifies other acceptors. Mechanistic studies of redox enzymes, including low-valent manganese complexes as catalase models, illustrate how metal centers and cofactors can mediate electron transfer in nitrogen-related redox chemistry.
Cofactor and metal dependence
In simple terms: Many of these enzymes use a helper molecule or metal ion to move electrons.
Cofactors such as flavins or metal ions are common in redox enzymes, and model complexes help dissect their roles. The dependence on a particular cofactor shapes inhibitor strategies, as seen in the development of isoquinolinone DHODH inhibitor isosteres that target a redox enzyme active site.
Regulation by redox-active gases
In simple terms: Small signaling gases can tune the activity of redox enzymes.
Nitrogen and sulfur signaling molecules can modulate redox enzyme activity. In sweet pepper fruit, endogenous H2S increases during ripening, and in vitro analysis shows that NADP-dependent isocitrate dehydrogenase activity is inhibited by H2S and NO, linking gasotransmitter signaling to redox control.
Physiological and metabolic context
In simple terms: These reactions are wired into larger nitrogen and energy pathways.
The activity operates within nitrogen metabolism, as illustrated by Salmonella typhimurium nit mutants that have a pleiotropic defect in nitrogen metabolism. It also contributes to biodegradation and environmental nitrogen transformations, where enzyme databases help organize the diversity of nitrogen-acting biocatalysts.
Key Genes Involved in GO:0016661 oxidoreductase activity, acting on other nitrogenous compounds as donors
The following genes and proteins are representative of enzymes and pathways connected to nitrogenous-donor redox chemistry and its study.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SMOX | Spermine oxidase oxidizes polyamines such as spermine | Substrate analogue studies with pentamines define specificity |
| DHODH | Dihydroorotate dehydrogenase, a redox enzyme target | Isoquinolinone inhibitor isosteres guide active-site targeting |
| ICDH | NADP-dependent isocitrate dehydrogenase, redox-regulated | Inhibited by H2S and NO in ripening fruit |
| nit genes | Pleiotropic nitrogen metabolism functions in Salmonella | Model for nitrogen pathway defects |
| Biodegrading enzyme genes | Enzymes that transform environmental nitrogenous compounds | Catalogued in the BiodEnz database |
| Mn-catalase models | Synthetic low-valent manganese complexes | Mechanistic models for redox catalysis |
| Sterol delta 7-reductase | Reductase acting on sterol intermediates | Inhibited by aza-homosteroid analogues |
| DOM-transforming bacterial genes | Bacteria-mediated dissolved organic matter transformation | Linked to algal bloom decay windows |
| Polyamine catabolism genes | Breakdown of nitrogenous polyamines | Relevant to spermine oxidase substrate range |
| Nitrogen regulatory genes | Control of nitrogen metabolism | Studied via nit mutant phenotypes |
| Redox cofactor biosynthesis genes | Produce flavin and metal cofactors | Support redox enzyme function |
| Environmental nitrogen cycle genes | Drive nitrogen transformations in ecosystems | Detected in biogeochemical studies |
| Enzyme database entries | Curated biodegrading enzymes | Enable comparative annotation |
| Inhibitor target genes | Enzymes targeted by small-molecule inhibitors | Relevant to DHODH inhibitor design |
| Gasotransmitter-responsive genes | Respond to H2S and NO | Link redox state to signaling |
| Sterol biosynthesis genes | Produce sterol intermediates | Studied with reductase inhibitors |
| Model metal-complex systems | Non-biological redox catalysts | Inform mechanism of electron transfer |
How Is oxidoreductase activity, acting on other nitrogenous compounds as donors Regulated?
Regulation of GO:0016661-related activities occurs at multiple levels. Substrate availability and redox state are key, as shown by the inhibition of NADP-dependent isocitrate dehydrogenase by H2S and NO during fruit ripening. Genetic control is illustrated by nit mutants of Salmonella typhimurium that cause pleiotropic defects in nitrogen metabolism. Enzyme activity can also be tuned by inhibitors that mimic transition states or substrate analogues, as seen with aza-homosteroid inhibition of sterol delta 7-reductase and with DHODH inhibitor isosteres. Environmental and microbial community context further shapes the flux through nitrogenous-donor redox reactions.
oxidoreductase activity, acting on other nitrogenous compounds as donors and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SMOX | Polyamine metabolism in cancer | Knockout and overexpression cell models with pentamine substrate profiling |
| DHODH | Proliferation and pyrimidine synthesis | Point-mutation models for inhibitor resistance |
| ICDH | Redox signaling and metabolic stress | Knock-in of redox-sensitive residues with H2S/NO treatment |
| nit genes | Bacterial nitrogen metabolism and virulence | Knockout mutants in Salmonella models |
| Sterol delta 7-reductase | Sterol biosynthesis disorders | Point-mutation and inhibitor-response assays |
Cancer and polyamine metabolism
Polyamine oxidation by enzymes such as spermine oxidase can generate reactive species and alter polyamine pools, which are relevant to cancer cell proliferation and stress responses. Substrate analogue studies with pentamines help define how these enzymes recognize polyamines and can inform inhibitor or probe design.
Infectious disease and nitrogen metabolism
Bacterial nitrogen metabolism is essential for adaptation to host environments. Pleiotropic nit mutants of Salmonella typhimurium demonstrate that defects in nitrogen handling can broadly impair growth and metabolism, making these pathways potential antibacterial targets.
Redox signaling in metabolic disease
Gasotransmitters such as H2S and NO modulate redox enzymes, including NADP-dependent isocitrate dehydrogenase, linking nitrogenous-donor redox chemistry to metabolic and signaling states that are altered in disease.
Drug discovery for redox enzymes
Redox enzymes are tractable drug targets. The identification of isoquinolinone DHODH inhibitor isosteres shows how medicinal chemistry can exploit redox enzyme active sites, a strategy that can be extended to other nitrogenous-donor oxidoreductases.
From oxidoreductase activity, acting on other nitrogenous compounds as donors-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is the enzyme required for polyamine oxidation? | SMOX knockout cell line |
| Does a mutation alter substrate specificity? | Point-mutation knock-in of the active site |
| Can a tagged enzyme be tracked in cells? | Tagged knock-in with fluorescent or affinity tag |
| Does overexpression change redox balance? | Overexpression cell model |
| Which nitrogen pathways are affected? | Knockout of nit genes in bacteria |
| How do inhibitors affect enzyme activity? | Wild-type and mutant isogenic lines |
How to Study the oxidoreductase activity, acting on other nitrogenous compounds as donors Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme kinetics with substrate analogues | Turnover and specificity | Polyamine oxidase substrate range |
| Inhibitor dose-response | Sensitivity of redox enzyme | DHODH inhibitor isostere testing |
| H2S/NO quantification | Gasotransmitter levels | Redox regulation of ICDH |
| Mutant phenotyping | Nitrogen metabolism defects | nit mutant characterization |
| Metagenomic profiling | Microbial nitrogen transformation potential | Algal bloom decay studies |
| Database mining | Enzyme family annotation | Biodegrading enzyme discovery |
| Metal-complex model chemistry | Electron transfer mechanism | Catalase model studies |
| Sterol reductase inhibition assays | Reductase activity | Sterol biosynthesis inhibitor testing |
Enzyme activity assays
Direct biochemical assays measure oxidation of nitrogenous donors and reduction of acceptors. Substrate analogue panels, such as pentamines for spermine oxidase, define specificity and kinetics. Inhibitor studies, including aza-homosteroid analogues, reveal mechanistic features of reductases.
Genetic perturbation and phenotyping
Knockout and mutant strains, such as nit mutants of Salmonella typhimurium, link gene function to nitrogen metabolism phenotypes. Comparative growth and metabolic profiling can reveal pleiotropic effects.
Redox and gasotransmitter profiling
Measuring H2S and NO levels alongside enzyme activity shows how redox signaling modulates enzymes like NADP-dependent isocitrate dehydrogenase. Such profiling can be combined with inhibitor treatments.
Environmental and metagenomic analysis
Nitrogen-transforming activities can be tracked in environmental samples, for example during algal bloom decay, to connect microbial genes to dissolved organic matter transformation. Curated enzyme databases support annotation and comparison.
How CRISPR Can Be Used to Study GO:0016661 oxidoreductase activity, acting on other nitrogenous compounds as donors
Knockout
CRISPR knockout of genes encoding nitrogenous-donor oxidoreductases, such as SMOX, can test whether the activity is required for polyamine metabolism and stress responses. Knockout of bacterial nit genes can model pleiotropic nitrogen defects.
Point Mutation
Point mutations in catalytic residues or substrate-binding pockets can dissect mechanism and inhibitor resistance, as pursued for redox enzyme targets like DHODH. Such edits help assign function to specific residues.
Knock-in
Knock-in of tags or reporter sequences allows tracking of enzymes such as ICDH under H2S/NO exposure, linking localization and abundance to redox regulation. Knock-in of disease-associated variants can model altered activity.
Overexpression
Overexpression of candidate oxidoreductases can amplify flux through nitrogenous-donor reactions and reveal downstream phenotypes, complementing inhibitor and knockout studies.
How EDITGENE Supports oxidoreductase activity, acting on other nitrogenous compounds as donors Research
Researchers studying oxidoreductase activity, acting on other nitrogenous compounds as donors-related genes often need to determine whether a candidate gene is causally involved in a specific redox or nitrogen-metabolism phenotype. EDITGENE provides CRISPR-based cell models and screening services to move from correlation to mechanism.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on other nitrogenous compounds as donors research.
Frequently Asked Questions About oxidoreductase activity, acting on other nitrogenous compounds as donors
What is GO:0016661?
GO:0016661 is the Gene Ontology molecular function oxidoreductase activity, acting on other nitrogenous compounds as donors, describing redox reactions where a nitrogenous group other than NH or NH2 donates electrons.
What does oxidoreductase activity, acting on other nitrogenous compounds as donors mean?
It means an enzyme removes electrons from a nitrogen-containing donor that is not an NH or NH2 group and transfers them to an acceptor, as defined by QuickGO and used in enzyme annotation.
What genes are involved in oxidoreductase activity, acting on other nitrogenous compounds as donors?
Representative genes include SMOX for polyamine oxidation, DHODH as a redox enzyme drug target, ICDH as a redox-regulated enzyme, and bacterial nit genes involved in nitrogen metabolism.
Which enzymes act on nitrogenous donors other than NH or NH2?
Examples include spermine oxidase acting on polyamines and various reductases and oxidases that use nitrogen-containing substrates, as illustrated in substrate analogue and inhibitor studies.
How is GO:0016661 studied experimentally?
It is studied with enzyme kinetics using substrate analogues, inhibitor dose-response assays, gasotransmitter profiling, mutant phenotyping, and metagenomic or database analyses.
Why is nitrogenous-donor redox chemistry important in bacteria?
Bacterial nitrogen metabolism is essential for growth and adaptation, and pleiotropic nit mutants show that defects in these pathways broadly affect nitrogen handling.
Can CRISPR be used to study these enzymes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can test the role of candidate oxidoreductases in redox and nitrogen metabolism.
What diseases are linked to nitrogenous-donor oxidoreductases?
They are linked to cancer through polyamine metabolism, to infectious disease through bacterial nitrogen metabolism, and to metabolic and redox signaling disorders.
How do H2S and NO affect these enzymes?
H2S and NO can inhibit redox enzymes such as NADP-dependent isocitrate dehydrogenase, linking gasotransmitter signaling to nitrogenous-donor redox control.
What model systems are used for GO:0016661 research?
Common models include knockout and overexpression cell lines, point-mutant isogenic lines, bacterial mutants, and environmental or metagenomic samples.
Conclusion
GO:0016661 captures a chemically defined but biologically broad class of redox reactions in which nitrogenous donors other than NH or NH2 drive reduction of an acceptor. Its study spans polyamine oxidation, bacterial nitrogen metabolism, redox signaling, drug discovery, and environmental nitrogen cycling. Because the term is mechanism-based rather than family-based, it is a powerful annotation and hypothesis-generation tool for researchers comparing diverse enzymes. Combining biochemical assays with CRISPR-based genetic models provides a rigorous path from annotation to function.
References
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- 3. Muñoz-Vargas MA et al.. 2018. Endogenous hydrogen sulfide (H(2)S) is up-regulated during sweet pepper (Capsicum annuum L.) fruit ripening. In vitro analysis shows that NADP-dependent isocitrate dehydrogenase (ICDH) activity is inhibited by H(2)S and NO.. Nitric Oxide 81:36-45 PMID: 30326260
- 4. Broach J et al.. 1976. Mutant strains (nit) of Salmonella typhimurium with a pleiotropic defect in nitrogen metabolism.. J Bacteriol 128(1):86-98 PMID: 10275
- 5. Zhang Z et al.. 2026. Molecular evidence for algal bloom decay as a critical window for bacteria-mediated DOM transformation toward more refractory forms.. Water Res 308(Pt A):126808 PMID: 42669264
- 6. Berggren G et al.. 2010. Synthesis and characterisation of low valent Mn-complexes as models for Mn-catalases.. Dalton Trans 39(45):11035-44 PMID: 20957239
- 7. Takao K et al.. 2013. Pentamines as substrate for human spermine oxidase.. Biol Pharm Bull 36(3):407-11 PMID: 23449327
- 8. Rahier A et al.. 1996. Sterol biosynthesis: strong inhibition of maize delta 5,7-sterol delta 7-reductase by novel 6-aza-B-homosteroids and other analogs of a presumptive carbocationic intermediate of the reduction reaction.. Biochemistry 35(22):7069-76 PMID: 8679532
