GO:0016728 oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016728 describes a redox reaction in which a CH2 group donates hydrogen or electrons and a disulfide group is reduced.
• Enzymes with this activity often use flavin, molybdenum cofactor, or iron-sulfur clusters to transfer electrons from CH2 substrates to disulfide acceptors.
• Representative enzymes include xanthine oxidoreductase, retinol saturase, and protochlorophyllide oxidoreductase.
• This activity is central to drug metabolism, vitamin A signaling, chlorophyll biosynthesis, and tetrapyrrole reduction.
• Dysregulation of these enzymes is linked to metabolic disorders, cancer, and developmental defects.
• CRISPR knockout, point mutation, knock-in, and overexpression models enable precise dissection of GO:0016728 enzyme function.
Description
GO:0016728, oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor, is a molecular function that catalyzes the oxidation of a CH2 group coupled to the reduction of a disulfide bond. This reaction is essential for diverse biological processes, including purine catabolism, retinol metabolism, and chlorophyll biosynthesis. Understanding this activity provides insight into redox homeostasis and metabolic regulation. Researchers study GO:0016728 to elucidate mechanisms of drug metabolism, vitamin A signaling, and plant photomorphogenesis. The enzymes involved often require complex cofactors such as molybdenum cofactor, flavin adenine dinucleotide (FAD), or iron-sulfur clusters. This article synthesizes authoritative QuickGO data and verified PubMed literature to provide a research-grade overview of GO:0016728, its genes, disease links, and experimental models.
oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor At A Glance
| GO ID | GO:0016728 |
|---|---|
| GO term | oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor |
| Ontology | molecular_function |
| Synonym | oxidoreductase activity, acting on CH or CH2 groups, disulphide as acceptor |
| Major function | Catalyzes oxidation of CH2 groups with reduction of disulfide bonds |
| Cofactors | Often requires FAD, molybdenum cofactor, or iron-sulfur clusters |
| Representative enzymes | Xanthine oxidoreductase, retinol saturase, protochlorophyllide oxidoreductase |
| Biological processes | Purine catabolism, retinol metabolism, chlorophyll biosynthesis, tetrapyrrole reduction |
What Is GO:0016728?
GO:0016728 is defined as catalysis of an oxidation-reduction reaction in which a CH2 group acts as a hydrogen or electron donor and reduces a disulfide group. In other words, the enzyme removes hydrogen from a carbon atom that is part of a CH2 group and transfers the electrons to a disulfide bond, breaking it into two thiol groups. This activity is distinct from other oxidoreductases because it specifically uses a disulfide as the electron acceptor and a CH2 group as the electron donor.
Why Is oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor Important in Cell Biology?
GO:0016728 is important because it governs redox reactions that are critical for cellular metabolism, detoxification, and signaling. Enzymes with this activity are involved in the metabolism of drugs and xenobiotics, the activation of vitamin A, and the biosynthesis of photosynthetic pigments. Dysregulation of these enzymes can lead to metabolic disorders, cancer, and developmental abnormalities. Therefore, studying GO:0016728 provides insights into fundamental biology and potential therapeutic targets.
• Enables purine catabolism and drug metabolism via xanthine oxidoreductase.
• Regulates retinol signaling and lipid metabolism through retinol saturase.
• Essential for chlorophyll biosynthesis and plant photomorphogenesis.
• Contributes to tetrapyrrole reduction in nitrogenase-like systems.
• Involved in polyamine metabolism and autophagy regulation in muscle aging.
• Provides a mechanism for disulfide bond reduction in redox homeostasis.
• Links to cancer through altered drug metabolism and oxidative stress.
• Potential target for metabolic disorders and neurodegenerative diseases.
• Facilitates electron transfer via flavin and molybdenum cofactors.
• Enables biotechnological applications in drug design and crop improvement.
Molecular Mechanism of oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor
Substrate binding and CH2 activation
In simple terms: The enzyme grabs a molecule that has a CH2 group and makes it ready to lose hydrogen.
The enzyme binds a substrate containing a CH2 group, positioning it near the catalytic site. For example, xanthine oxidoreductase binds xanthine or hypoxanthine, while retinol saturase binds retinol. The CH2 group is activated for hydrogen abstraction, often through interaction with a cofactor such as FAD or molybdenum cofactor.
Electron transfer to disulfide acceptor
In simple terms: The hydrogen removed from the CH2 group is passed to a disulfide bond, breaking it into two thiols.
The electrons derived from the CH2 group are transferred to a disulfide group, reducing it to two cysteine thiols. This step may involve intermediate electron carriers such as iron-sulfur clusters or flavin semiquinones. The disulfide acceptor can be part of the same enzyme or a separate protein, as seen in protochlorophyllide oxidoreductase where light-driven electron transfer reduces a disulfide.
Cofactor regeneration and catalytic cycle
In simple terms: The enzyme resets itself so it can perform the reaction again.
After reduction of the disulfide, the enzyme must regenerate its oxidized cofactor. For flavoenzymes, FAD is reoxidized by molecular oxygen or another electron acceptor. Molybdenum cofactor enzymes cycle between Mo(VI) and Mo(IV) states. In light-dependent protochlorophyllide oxidoreductase, the catalytic cycle is driven by photon absorption.
Regulation by light and redox state
In simple terms: Some enzymes in this family are turned on by light or by the cell's redox balance.
Protochlorophyllide oxidoreductase is activated by light, which triggers a conformational change and electron transfer. Other enzymes, such as xanthine oxidoreductase, are regulated by reversible sulfhydryl oxidation or proteolytic cleavage. Retinol saturase activity may be influenced by retinol availability and cellular redox status.
Key Genes Involved in GO:0016728 oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor
The following genes encode enzymes that exhibit GO:0016728 activity or are directly involved in its catalytic mechanism.
| Gene | Major Role | Research Relevance |
|---|---|---|
| XDH | Xanthine oxidoreductase; catalyzes oxidation of xanthine to uric acid with disulfide reduction | Drug metabolism, gout, oxidative stress |
| RETSAT | Retinol saturase; saturates retinol to retinol saturate using a disulfide acceptor | Vitamin A signaling, lipid metabolism, cancer |
| POR | Protochlorophyllide oxidoreductase; light-driven reduction of protochlorophyllide | Chlorophyll biosynthesis, photomorphogenesis |
| NifB | Nitrogenase-like enzyme involved in tetrapyrrole reduction | Tetrapyrrole biosynthesis, nitrogen fixation |
| MOCS1 | Molybdenum cofactor synthesis; required for xanthine oxidoreductase activity | Molybdenum cofactor deficiency, metabolic disorders |
| MOCS2 | Molybdenum cofactor synthesis; required for xanthine oxidoreductase activity | Molybdenum cofactor deficiency |
| GEPHYRIN | Anchor protein for xanthine oxidoreductase in membranes | Enzyme localization, drug metabolism |
| FAD synthase | Provides FAD cofactor for flavoenzymes | Flavoenzyme function, redox biology |
| NFS1 | Iron-sulfur cluster assembly for redox enzymes | Iron-sulfur cluster biogenesis |
| ISCU | Iron-sulfur cluster scaffold protein | Iron-sulfur cluster assembly |
| CIAO1 | Cytosolic iron-sulfur protein assembly | Iron-sulfur cluster maturation |
| PORA | Protochlorophyllide oxidoreductase A isoform | Light-dependent chlorophyll synthesis |
| PORB | Protochlorophyllide oxidoreductase B isoform | Light-dependent chlorophyll synthesis |
| PORC | Protochlorophyllide oxidoreductase C isoform | Light-dependent chlorophyll synthesis |
| RETSATL | Retinol saturase-like protein | Retinoid metabolism |
| XDH variant | Xanthine dehydrogenase isoform | Purine metabolism, drug activation |
| AOX1 | Aldehyde oxidase; related molybdenum enzyme | Drug metabolism, redox reactions |
How Is oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor Regulated?
GO:0016728 activity is regulated at multiple levels. Xanthine oxidoreductase is controlled by reversible sulfhydryl oxidation, proteolytic cleavage, and transcriptional induction during inflammation. Retinol saturase expression is influenced by retinoic acid and lipid status. Protochlorophyllide oxidoreductase is activated by light and regulated by phytochrome signaling. Additionally, cofactor availability, such as molybdenum cofactor or FAD, modulates enzyme activity.
oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| XDH | Hyperuricemia, gout, drug metabolism | Xdh knockout mouse, point mutation knock-in |
| RETSAT | Cancer, lipid metabolism disorders | Retsat knockout and overexpression cell lines |
| MOCS1 | Molybdenum cofactor deficiency | Mocs1 knockout zebrafish or mouse |
| POR | Plant photomorphogenesis defects | Por knockout Arabidopsis, point mutation |
| NifB | Tetrapyrrole biosynthesis defects | NifB knockout bacteria, knock-in |
Metabolic disorders and drug metabolism
Xanthine oxidoreductase (XDH) dysfunction leads to xanthinuria and hyperuricemia, and its activity influences the metabolism of drugs such as 6-mercaptopurine. Molybdenum cofactor deficiency, caused by mutations in MOCS1 or MOCS2, results in loss of xanthine oxidoreductase activity and severe neurological symptoms.
Cancer and oxidative stress
Altered expression of xanthine oxidoreductase and retinol saturase has been observed in various cancers, where they contribute to oxidative stress and retinoid signaling. Targeting these enzymes may modulate tumor growth and drug resistance.
Muscle aging and autophagy
Polyamine metabolism, which intersects with redox enzymes, regulates autophagy and skeletal muscle regeneration during aging. Dysregulation of these pathways may contribute to sarcopenia and age-related muscle loss.
Plant development and photomorphogenesis
Protochlorophyllide oxidoreductase is essential for chlorophyll biosynthesis and light-dependent greening in plants. Mutations in POR genes cause defects in photomorphogenesis and seedling development.
From oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does XDH loss alter drug metabolism? | Xdh knockout mouse or HepG2 knockout cells |
| How does RETSAT mutation affect retinol signaling? | Retsat point mutation knock-in cell lines |
| What is the role of POR in light-dependent greening? | Por knockout Arabidopsis and overexpression lines |
| Can MOCS1 rescue molybdenum cofactor deficiency? | Mocs1 knock-in mouse model |
| Does NifB reduction require specific iron-sulfur clusters? | NifB knockout bacteria with tagged knock-in |
| How does polyamine metabolism regulate autophagy in muscle? | Polyamine enzyme knockout muscle cells |
How to Study the oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Spectrophotometric assay | Substrate oxidation or disulfide reduction | Xanthine oxidoreductase activity |
| HPLC | Retinol consumption | Retinol saturase activity |
| CRISPR knockout screen | Gene essentiality for redox activity | Identify novel GO:0016728 regulators |
| Affinity purification-MS | Protein-protein interactions | Find disulfide acceptors |
| X-ray crystallography | Three-dimensional structure | Active site mechanism |
| Cryo-EM | Structure of large complexes | Molybdenum enzyme complexes |
| Live-cell imaging | Subcellular localization | POR dynamics in chloroplasts |
| RNA-seq | Transcriptional changes | Response to oxidative stress |
Enzymatic activity assays
Direct measurement of GO:0016728 activity can be performed using spectrophotometric assays that monitor disulfide reduction or substrate oxidation. For xanthine oxidoreductase, xanthine oxidation to uric acid is measured at 295 nm. For retinol saturase, retinol consumption is tracked by HPLC.
CRISPR-based genetic screens
Genome-wide CRISPR knockout screens can identify genes required for GO:0016728 activity. Cells are challenged with substrates and disulfide acceptors, and sgRNA enrichment is analyzed by next-generation sequencing.
Proteomics and interactomics
Affinity purification coupled to mass spectrometry can identify proteins that interact with GO:0016728 enzymes, revealing disulfide acceptors and regulatory partners. Proximity labeling can map the redox interactome.
Structural biology and imaging
X-ray crystallography and cryo-EM reveal the active site architecture of enzymes like xanthine oxidoreductase and protochlorophyllide oxidoreductase. Fluorescence imaging of tagged enzymes in live cells shows subcellular localization and dynamics.
How CRISPR Can Be Used to Study GO:0016728 oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor
Knockout
CRISPR knockout of XDH, RETSAT, or POR eliminates GO:0016728 activity, enabling loss-of-function studies in cell lines and animal models. Knockout cells can be used to measure metabolic flux and drug sensitivity.
Point Mutation
Point mutations in catalytic residues of XDH or RETSAT can dissect the role of specific amino acids in CH2 oxidation and disulfide reduction. CRISPR base editing or prime editing introduces precise mutations without indels.
Knock-in
Knock-in of tagged versions of GO:0016728 enzymes (e.g., GFP or HA) allows visualization and immunoprecipitation. Knock-in of disease-associated mutations models human disorders.
Overexpression
Overexpression of XDH, RETSAT, or POR in cell lines increases GO:0016728 activity, useful for studying downstream effects and drug screening. Inducible overexpression systems provide temporal control.
How EDITGENE Supports oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor Research
Researchers studying oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor-related genes often need to determine whether a candidate gene is causally involved in redox metabolism, drug response, or disease. EDITGENE provides end-to-end CRISPR services to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor research.
Frequently Asked Questions About oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor
What is GO:0016728?
GO:0016728 is a molecular function term describing oxidoreductase activity that acts on CH or CH2 groups with a disulfide as the electron acceptor.
What genes are involved in oxidoreductase activity, acting on CH or CH2 groups, disulfide as acceptor?
Key genes include XDH, RETSAT, POR, NifB, and MOCS1/MOCS2, which encode enzymes or cofactor synthesis proteins.
What diseases are linked to GO:0016728?
Diseases include hyperuricemia, gout, molybdenum cofactor deficiency, cancer, and muscle aging.
How is GO:0016728 regulated?
It is regulated by light, redox state, cofactor availability, and transcriptional induction.
What cofactors are required for GO:0016728?
Common cofactors include FAD, molybdenum cofactor, and iron-sulfur clusters.
Can CRISPR knockout be used to study GO:0016728?
Yes, CRISPR knockout of XDH, RETSAT, or POR eliminates activity and enables loss-of-function studies.
What is the role of xanthine oxidoreductase in drug metabolism?
Xanthine oxidoreductase metabolizes drugs like 6-mercaptopurine and contributes to oxidative stress.
How does retinol saturase function?
Retinol saturase catalyzes the saturation of retinol using a disulfide acceptor, affecting vitamin A signaling.
What is protochlorophyllide oxidoreductase?
It is a light-dependent enzyme that reduces protochlorophyllide to chlorophyllide during chlorophyll biosynthesis.
How can I model GO:0016728 mutations?
EDITGENE offers CRISPR knockout, point mutation, knock-in, and overexpression models for precise functional studies.
Conclusion
GO:0016728 represents a critical redox activity that bridges CH2 oxidation and disulfide reduction, impacting metabolism, development, and disease. The enzymes involved, such as xanthine oxidoreductase, retinol saturase, and protochlorophyllide oxidoreductase, are attractive targets for therapeutic and biotechnological applications. CRISPR-based models provide powerful tools to dissect their mechanisms and roles in human health and plant biology.
References
- 1. Battelli MG et al.. 2016. Xanthine Oxidoreductase in Drug Metabolism: Beyond a Role as a Detoxifying Enzyme.. Curr Med Chem 23(35):4027-4036 PMID: 27458036
- 2. Romero E et al.. 2014. Alcohol oxidation by flavoenzymes.. Biomol Concepts 5(4):299-318 PMID: 25372761
- 3. Weber P et al.. 2020. Retinol Saturase: More than the Name Suggests.. Trends Pharmacol Sci 41(6):418-427 PMID: 32345479
- 4. Kisker C et al.. 1997. Molybdenum-cofactor-containing enzymes: structure and mechanism.. Annu Rev Biochem 66:233-67 PMID: 9242907
- 5. Layer G et al.. 2017. Reduction of Chemically Stable Multibonds: Nitrogenase-Like Biosynthesis of Tetrapyrroles.. Adv Exp Med Biol 925:147-161 PMID: 27957709
- 6. Attili L et al.. 2026. Polyamines and autophagy as a dynamic regulatory network in skeletal muscle regeneration and aging.. Mech Ageing Dev 231:112188 PMID: 42086115
- 7. Gabruk M et al.. 2015. Light-Dependent Protochlorophyllide Oxidoreductase: Phylogeny, Regulation, and Catalytic Properties.. Biochemistry 54(34):5255-62 PMID: 26230427
- 8. Heyes DJ et al.. 2021. Photocatalysis as the 'master switch' of photomorphogenesis in early plant development.. Nat Plants 7(3):268-276 PMID: 33686224
