GO:0016712 oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016712 describes a molecular function: a redox reaction that uses reduced flavin or flavoprotein as one electron donor, a second donor substrate, and incorporates one atom of molecular oxygen into the product.
• This activity is classically associated with cytochrome P450 monooxygenases and flavoprotein-linked monooxygenases, which hydroxylate or epoxidize substrates using NAD(P)H-derived reducing equivalents.
• Flavin-dependent monooxygenases are widely distributed across bacteria, fungi, plants, and animals, where they participate in metabolism, detoxification, and biosynthesis.
• The catalytic cycle requires a reduced flavin cofactor, molecular oxygen, and a second donor; uncoupling can generate reactive oxygen species.
• Dysregulation of these enzymes is linked to metabolic disorders, cancer, and altered drug metabolism, making them important pharmacological targets.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models enable causal dissection of GO:0016712 enzyme function in disease and metabolism.
Description
GO:0016712, oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen, is a molecular function term that captures a large and diverse class of monooxygenase reactions. These enzymes use reduced flavin or a flavoprotein as one electron donor and a second substrate as the other donor, while incorporating a single oxygen atom from molecular oxygen into the product. This chemistry is central to oxidative metabolism, including hydroxylation, epoxidation, and xenobiotic detoxification. The term is often associated with cytochrome P450 activity and flavoprotein-linked monooxygenase activity, reflecting its historical annotation to microsomal and bacterial systems. Understanding this activity is essential for researchers studying drug metabolism, hormone biosynthesis, and redox signaling. Flavin-dependent monooxygenases are found across all domains of life and often function as part of larger electron transfer chains involving NAD(P)H, flavin reductases, and terminal oxygenases. Because these enzymes can generate reactive oxygen species when uncoupled, their regulation is critical for cellular redox homeostasis. This article summarizes the definition, mechanism, key genes, disease links, and research methods for GO:0016712, with a focus on how CRISPR models can be used to study its function.
oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen At A Glance
| GO ID | GO:0016712 |
|---|---|
| GO term | oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen |
| Ontology | molecular_function |
| Synonym | aryl-4-monooxygenase activity; aryl hydrocarbon hydroxylase activity; cytochrome p450 activity; flavoprotein-linked monooxygenase activity; flavoprotein monooxygenase activity; microsomal monooxygenase activity; unspecific monooxygenase activity; xenobiotic monooxygenase activity |
| Major function | Catalyzes monooxygenation using reduced flavin/flavoprotein and a second donor, incorporating one atom of oxygen into the substrate. |
| Cofactors | Reduced flavin (FADH2/FMNH2) or flavoprotein, molecular oxygen, and often NAD(P)H as ultimate electron source. |
| Typical reactions | Hydroxylation, epoxidation, and oxidative demethylation of endogenous and xenobiotic substrates. |
| Representative enzymes | Cytochrome P450 monooxygenases, flavin-containing monooxygenases, and bacterial flavoprotein hydroxylases. |
| Subcellular context | Often microsomal or membrane-associated, but also found in soluble bacterial and mitochondrial systems. |
What Is GO:0016712?
GO:0016712 is defined as catalysis of an oxidation-reduction reaction in which hydrogen or electrons are transferred from reduced flavin or flavoprotein and one other donor, and one atom of oxygen is incorporated into one donor. In other words, the enzyme uses a reduced flavin cofactor to activate molecular oxygen, then inserts one oxygen atom into a substrate while the other oxygen atom is reduced to water. This definition covers a wide range of monooxygenases, including cytochrome P450 enzymes and flavoprotein monooxygenases, and is distinct from dioxygenases that incorporate both oxygen atoms.
Why Is oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen Important in Cell Biology?
GO:0016712 is important because it defines a fundamental redox chemistry that underpins drug metabolism, hormone synthesis, and detoxification of environmental chemicals. Enzymes with this activity are major determinants of pharmacokinetics and can activate or inactivate therapeutic compounds. They also contribute to oxidative stress when uncoupled, linking them to inflammation and degenerative diseases. Because flavin-dependent monooxygenases are widespread and often essential, they are attractive targets for antimicrobial and anticancer drug development.
• GO:0016712 enzymes catalyze key steps in steroid hormone biosynthesis and vitamin D metabolism.
• They are central to phase I drug metabolism, affecting the half-life and activity of many pharmaceuticals.
• Flavin-dependent monooxygenases participate in bacterial antibiotic resistance and virulence.
• Uncoupled turnover can produce reactive oxygen species, contributing to oxidative stress.
• Mutations in these enzymes are associated with metabolic disorders and altered drug responses.
• They are involved in the biosynthesis of natural products and secondary metabolites.
• GO:0016712 activity is important for detoxification of xenobiotics and environmental pollutants.
• These enzymes are targets for mechanism-based inhibitors in cancer and infectious disease.
• Flavoprotein monooxygenases are used in biocatalysis for selective hydroxylation.
• Understanding their regulation can inform personalized medicine and drug development.
Mechanism, Genes and Research Methods of GO:0016712
What Happens During oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen?
In simple terms: The enzyme uses a reduced flavin to split oxygen and insert one oxygen atom into a target molecule.
The reaction begins with reduction of the flavin cofactor by NAD(P)H or another electron donor, generating reduced flavin or flavoprotein. Molecular oxygen then binds and is activated, leading to the formation of a flavin hydroperoxide intermediate. This intermediate transfers one oxygen atom to the second donor substrate, while the other oxygen atom is reduced to water. The overall outcome is monooxygenation of the substrate, such as hydroxylation or epoxidation.
Electron Transfer and Flavin Reduction
In simple terms: Electrons are delivered to the flavin so it can activate oxygen.
In many systems, a flavin reductase or a reductase domain supplies electrons from NAD(P)H to the flavin cofactor. The reduced flavin can be free or bound within a flavoprotein, depending on the enzyme class. This step is essential for priming the enzyme for oxygen activation.
Oxygen Activation and Substrate Oxygenation
In simple terms: Oxygen is split, and one atom is inserted into the substrate.
The reduced flavin reacts with molecular oxygen to form a hydroperoxyflavin intermediate, which is the key oxygenating species. The second donor substrate then undergoes hydroxylation or epoxidation, incorporating one oxygen atom. The remaining oxygen atom is reduced to water, completing the catalytic cycle.
Uncoupling and Reactive Oxygen Species
In simple terms: Sometimes the enzyme leaks reactive oxygen instead of making product.
When substrate availability is low or electron transfer is inefficient, the hydroperoxyflavin can decompose to hydrogen peroxide or other reactive oxygen species. This uncoupling is a source of oxidative stress and can contribute to toxicity. Regulation of electron supply and substrate binding helps minimize uncoupling.
Structural and Cellular Context
In simple terms: These enzymes are often attached to membranes or part of larger complexes.
Many GO:0016712 enzymes are microsomal or membrane-bound, such as cytochrome P450 monooxygenases in the endoplasmic reticulum. Others are soluble bacterial enzymes that use free flavin or flavoprotein partners. The cellular context influences substrate access and electron transfer efficiency.
Key Genes Involved in GO:0016712 oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
The following genes and proteins are representative of enzymes and electron transfer partners associated with GO:0016712 activity, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CYP1A1 | Cytochrome P450 monooxygenase that hydroxylates aryl hydrocarbons | Model for xenobiotic metabolism and cancer susceptibility |
| CYP1A2 | Cytochrome P450 monooxygenase involved in drug and carcinogen activation | Studied for drug metabolism and toxicity |
| CYP2D6 | Cytochrome P450 monooxygenase metabolizing many drugs | Pharmacogenetics and personalized medicine |
| CYP3A4 | Major drug-metabolizing cytochrome P450 | Central to pharmacokinetics and drug-drug interactions |
| CYP19A1 | Aromatase, a cytochrome P450 that converts androgens to estrogens | Target in breast cancer and hormone therapy |
| FMO1 | Flavin-containing monooxygenase that oxidizes xenobiotics | Detoxification and drug metabolism |
| FMO3 | Flavin-containing monooxygenase that metabolizes trimethylamine | Linked to trimethylaminuria and drug responses |
| FMO5 | Flavin-containing monooxygenase with roles in metabolism | Emerging target in metabolic research |
| NDOR1 | NADPH-dependent diflavin oxidoreductase that supplies electrons | Electron transfer partner for monooxygenases |
| POR | Cytochrome P450 oxidoreductase, a flavoprotein that transfers electrons | Essential for microsomal P450 activity |
| FDXR | Ferredoxin reductase, a flavoprotein involved in electron transfer | Supports mitochondrial P450 and redox balance |
| MICAL1 | Flavin-dependent monooxygenase acting on actin | Redox regulation of cytoskeleton |
| MICAL2 | Flavin-dependent monooxygenase involved in actin oxidation | Roles in cell motility and cancer |
| SQLE | Squalene monooxygenase, a flavoprotein monooxygenase in sterol biosynthesis | Cholesterol metabolism and cancer |
| BHA1 | Bacterial flavin-dependent monooxygenase | Model for biocatalysis and antibiotic resistance |
| HpaB | Flavoprotein monooxygenase in aromatic compound degradation | Bioremediation and enzymology |
| RebH | Flavin-dependent halogenase related to monooxygenases | Natural product biosynthesis |
How Is oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen Regulated?
GO:0016712 activity is regulated at multiple levels, including transcriptional control of the enzyme genes, availability of NAD(P)H, and the redox state of the flavin cofactor. Electron transfer from reductase partners such as POR or NDOR1 is a key determinant of catalytic efficiency. In some systems, substrate availability and product inhibition modulate flux through the monooxygenase reaction. Post-translational modifications and protein-protein interactions can also influence enzyme activity.
oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CYP1A1 | Cancer susceptibility and xenobiotic activation | Knockout and overexpression in cancer cell lines |
| FMO3 | Trimethylaminuria and drug metabolism | Point mutation knock-in in hepatocyte models |
| CYP19A1 | Breast cancer and estrogen biosynthesis | Knockout in breast cancer cells and xenografts |
| MICAL1 | Cytoskeletal redox regulation and cancer | Knockout and tagged knock-in in mammalian cells |
| SQLE | Cholesterol metabolism and cancer | Overexpression and knockout in metabolic cell models |
Cancer and Xenobiotic Metabolism
Cytochrome P450 enzymes with GO:0016712 activity can activate procarcinogens and influence cancer risk. Altered expression of these enzymes in tumors can affect drug sensitivity and resistance. Targeting these activities is a strategy in anticancer drug development.
Metabolic and Endocrine Disorders
Mutations in flavin-dependent monooxygenases can cause metabolic disorders, such as trimethylaminuria due to FMO3 deficiency. Aromatase (CYP19A1) dysfunction affects estrogen biosynthesis and is linked to endocrine disorders.
Neurodegeneration and Oxidative Stress
Uncoupled GO:0016712 activity can generate reactive oxygen species, contributing to oxidative stress in neurodegenerative diseases. Regulated methionine oxidation by monooxygenases is implicated in redox signaling and neuronal function.
Infectious Disease and Antimicrobial Resistance
Bacterial flavin-dependent monooxygenases can contribute to antibiotic resistance and virulence. Inhibitors of these enzymes are being explored as antimicrobial agents.
From oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate monooxygenase affect drug metabolism? | CRISPR knockout in hepatocyte-like cells |
| Does a specific point mutation alter catalytic activity? | Point mutation knock-in in isogenic cell lines |
| How does a disease-associated variant affect enzyme function? | Knock-in of the variant allele in cell models |
| Where is the enzyme localized in cells? | Tagged knock-in with fluorescent or affinity tags |
| Does overexpression of the enzyme increase oxidative stress? | Overexpression in mammalian cells |
| Can a bacterial monooxygenase be repurposed for biocatalysis? | Heterologous expression in E. coli |
How to Study the oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NAD(P)H oxidation assay | Enzyme turnover and kinetics | Screening inhibitors of monooxygenases |
| LC-MS metabolomics | Substrate and product levels | Detecting hydroxylated metabolites |
| RNA-seq | Gene expression changes | Profiling monooxygenase genes in disease models |
| Proteomics | Protein abundance and modifications | Quantifying enzyme and partner proteins |
| Cryo-EM | Three-dimensional structure | Understanding catalytic mechanism |
| Site-directed mutagenesis | Residue-specific function | Mapping active site residues |
| CRISPR knockout | Loss-of-function phenotype | Causal gene validation |
| Overexpression | Gain-of-function phenotype | Testing sufficiency in cells |
Enzymatic Activity Assays
Monooxygenase activity can be measured using substrate conversion assays, often coupled to NAD(P)H oxidation. These assays determine kinetic parameters and inhibitor sensitivity.
Gene Expression and Proteomics
RNA-seq and quantitative proteomics can quantify expression of GO:0016712 enzymes and their electron transfer partners. These methods help link expression changes to metabolic phenotypes.
Metabolomics and Flux Analysis
Metabolomics can detect products of monooxygenase reactions, such as hydroxylated metabolites. Stable isotope tracing can reveal flux through these pathways.
Structural and Biophysical Methods
X-ray crystallography and cryo-EM can reveal the architecture of flavin-dependent monooxygenases and their complexes. These methods inform inhibitor design and mechanism.
How CRISPR Can Be Used to Study GO:0016712 oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
Knockout
CRISPR knockout of a GO:0016712 enzyme gene can abolish its activity, allowing researchers to test its role in drug metabolism, oxidative stress, and disease phenotypes. Knockout cell lines are valuable for identifying compensatory pathways and for drug sensitivity screens.
Point Mutation
Point mutation knock-in can model naturally occurring variants or catalytic dead mutants, revealing how specific residues affect monooxygenase activity. This approach is useful for studying disease-associated polymorphisms.
Knock-in
Knock-in of tags or reporter sequences enables visualization and purification of the enzyme in its native context. Knock-in of disease alleles can create isogenic models for functional studies.
Overexpression
Overexpression of a GO:0016712 enzyme can increase metabolic flux and reactive oxygen species production, helping to establish sufficiency in cellular phenotypes. It is also used for biotransformation studies.
How EDITGENE Supports oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen Research
Researchers studying oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen-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 to enable such causal studies.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen research.
Frequently Asked Questions About oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
What is GO:0016712?
GO:0016712 is a Gene Ontology molecular function term for oxidoreductase activity that uses reduced flavin or flavoprotein as one donor, incorporates one atom of oxygen into a substrate, and reduces the other oxygen atom to water.
What genes are involved in GO:0016712?
Genes encoding cytochrome P450 enzymes (e.g., CYP1A1, CYP3A4, CYP19A1), flavin-containing monooxygenases (e.g., FMO3), and electron transfer partners such as POR and NDOR1 are associated with this activity.
What is the function of oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen?
It catalyzes monooxygenation reactions, such as hydroxylation and epoxidation, using reduced flavin and a second donor substrate.
Which diseases are linked to GO:0016712?
Altered activity is linked to cancer, metabolic disorders like trimethylaminuria, endocrine disorders, and oxidative stress-related neurodegeneration.
How can CRISPR be used to study GO:0016712?
CRISPR knockout, point mutation, knock-in, and overexpression models can test the causal role of specific monooxygenase genes in metabolism and disease.
What are the synonyms for GO:0016712?
Synonyms include cytochrome P450 activity, flavoprotein monooxygenase activity, microsomal monooxygenase activity, and xenobiotic monooxygenase activity.
What cofactors are required for GO:0016712?
Reduced flavin (FADH2 or FMNH2) or a flavoprotein, molecular oxygen, and often NAD(P)H as the ultimate electron donor are required.
How is GO:0016712 activity regulated?
It is regulated by electron supply from reductase partners, substrate availability, transcriptional control, and the redox state of the flavin cofactor.
What methods are used to measure GO:0016712 activity?
Enzymatic assays, metabolomics, RNA-seq, proteomics, and structural methods are commonly used.
Why is GO:0016712 important for drug development?
Many drugs are metabolized by enzymes with this activity, so understanding it helps predict drug efficacy, toxicity, and interactions.
Conclusion
GO:0016712 defines a versatile and biologically important monooxygenase activity that uses reduced flavin to insert one oxygen atom into diverse substrates. Its enzymes are central to drug metabolism, hormone biosynthesis, detoxification, and redox signaling, and their dysfunction is linked to cancer, metabolic disorders, and oxidative stress. CRISPR-based cell models provide powerful tools to dissect the causal roles of these enzymes and to develop targeted therapies.
References
- 2. Deller S et al.. 2008. Flavin-dependent quinone reductases.. Cell Mol Life Sci 65(1):141-60 PMID: 17938860
- 5. Manta B et al.. 2017. Regulated methionine oxidation by monooxygenases.. Free Radic Biol Med 109:141-155 PMID: 28229915
- 6. Buey RM et al.. 2021. Unexpected diversity of ferredoxin-dependent thioredoxin reductases in cyanobacteria.. Plant Physiol 186(1):285-296 PMID: 33599267
