GO:0004602 glutathione peroxidase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004602 glutathione peroxidase activity catalyzes the reduction of hydrogen peroxide (H2O2) to water using reduced glutathione (GSH) as the electron donor, yielding oxidized glutathione (GSSG).
• The selenoprotein GPX1 is the major cytosolic and plasma isoform, and its activity is influenced by selenium status, physical activity, and gender.
• Glutathione peroxidase activity protects cells from oxidative stress and lipid peroxidation, and is implicated in cancer, cardiovascular disease, neurodegeneration, and kidney transplant outcomes.
• Exercise training stimulates the release of GPX1-enriched extracellular vesicles that promote angiogenesis, linking this enzymatic activity to systemic redox signaling.
• Overexpression of phospholipid hydroperoxide glutathione peroxidase (GPX4) modulates acetyl-CoA and lyso-PAF acetyltransferase activity, connecting glutathione peroxidase activity to lipid mediator synthesis.
• CRISPR-based knockout, knock-in, point-mutation, and overexpression models enable precise dissection of glutathione peroxidase gene function in oxidative stress and disease.
Description
Glutathione peroxidase activity (GO:0004602) is a molecular function defined as the catalysis of the reaction: 2 glutathione + H2O2 = oxidized glutathione + 2 H2O. This enzymatic activity is central to cellular antioxidant defense, converting hydrogen peroxide and organic hydroperoxides to water or alcohols while oxidizing reduced glutathione (GSH) to glutathione disulfide (GSSG). The reaction is catalyzed by a family of selenium-dependent and selenium-independent enzymes, with GPX1 being the most abundant and widely studied isoform in mammalian cells. Researchers study glutathione peroxidase activity to understand redox homeostasis, oxidative stress-related diseases, and the protective effects of selenium and exercise. The activity is measured in plasma, erythrocytes, and tissues, and its levels are influenced by gender, physical activity, and nutritional status. Beyond its classical antioxidant role, glutathione peroxidase activity participates in lipid mediator synthesis and extracellular vesicle-mediated signaling, expanding its biological significance. This article provides a comprehensive overview of the mechanism, key genes, disease associations, and research methods for studying GO:0004602.
glutathione peroxidase activity At A Glance
| GO ID | GO:0004602 |
|---|---|
| GO term | glutathione peroxidase activity |
| Ontology | molecular_function |
| Synonym | glutathione:hydrogen-peroxide oxidoreductase activity; GSH peroxidase activity; non-selenium glutathione peroxidase activity; reduced glutathione peroxidase activity; selenium-glutathione peroxidase activity |
| Definition | Catalysis of the reaction: 2 glutathione + H2O2 = oxidized glutathione + 2 H2O. |
| Major function | Reduction of hydrogen peroxide and organic hydroperoxides using glutathione as an electron donor, protecting cells from oxidative damage. |
| Representative enzymes | GPX1, GPX2, GPX3, GPX4, GPX5, GPX6, GPX7, GPX8. |
| Cofactors | Selenium (as selenocysteine) for selenoprotein isoforms; NADPH via glutathione reductase for recycling GSSG to GSH. |
| Tissue distribution | Ubiquitous; high in erythrocytes, liver, kidney, lung, and plasma (GPX3). |
What Is GO:0004602?
Glutathione peroxidase activity (GO:0004602) is the catalytic activity that reduces hydrogen peroxide (H2O2) to water (H2O) using two molecules of reduced glutathione (GSH) as electron donors, producing one molecule of oxidized glutathione (GSSG). The reaction is: 2 glutathione + H2O2 = oxidized glutathione + 2 H2O. This activity is also known as glutathione:hydrogen-peroxide oxidoreductase activity, GSH peroxidase activity, non-selenium glutathione peroxidase activity, reduced glutathione peroxidase activity, and selenium-glutathione peroxidase activity. It is a molecular_function term in the Gene Ontology, and it is carried out by enzymes such as GPX1, GPX2, GPX3, GPX4, GPX5, GPX6, GPX7, and GPX8 in humans, with varying substrate specificities and tissue distributions.
Why Is glutathione peroxidase activity Important in Cell Biology?
Glutathione peroxidase activity is a cornerstone of cellular antioxidant defense, directly neutralizing hydrogen peroxide and lipid hydroperoxides that would otherwise damage DNA, proteins, and membranes. Its dysregulation is linked to cancer, cardiovascular disease, neurodegeneration, and transplant-related oxidative stress, making it a critical target for understanding redox biology and developing therapeutic strategies. Moreover, the activity is modulated by lifestyle factors such as exercise and diet, and it participates in intercellular signaling via extracellular vesicles, highlighting its broad physiological relevance.
• Protects cells from oxidative stress by reducing H2O2 and lipid peroxides.
• Modulates susceptibility to lipid peroxidation in plasma and low-density lipoprotein, relevant to atherosclerosis.
• Influenced by selenium status, with dietary selenium increasing cellular glutathione peroxidase activity in kidney transplant recipients.
• Affected by physical activity and gender, with plasma glutathione peroxidase levels varying in healthy young adults.
• Exercise training stimulates release of GPX1-enriched extracellular vesicles that promote angiogenesis.
• Overexpression of GPX4 modulates acetyl-CoA and lyso-PAF acetyltransferase activity, linking to lipid mediator synthesis.
• Swim training increases glutathione peroxidase activity in the spinal cord of ALS mice and ameliorates hyperlocomotion.
• Preconditioning exercise inhibits neuronal ferroptosis via skeletal muscle-derived exosomes regulating the miR-484/ACSL4 axis, involving glutathione peroxidase activity.
• Ascorbic acid supplementation affects oxidative stress markers after exercise, with potential interactions with glutathione peroxidase activity.
• Lack of association between physical activity and plasma glutathione peroxidase levels in smokers suggests complex regulation.
What Happens During glutathione peroxidase activity?
Substrate binding and selenocysteine activation
In simple terms: The enzyme grabs hydrogen peroxide and glutathione to start the reaction.
Glutathione peroxidase enzymes contain a catalytic selenocysteine (Sec) residue in selenoprotein isoforms such as GPX1 and GPX4. The selenol group (-SeH) is highly nucleophilic and attacks the peroxide substrate, forming a selenenic acid intermediate. Reduced glutathione (GSH) then serves as the electron donor, reducing the intermediate and releasing water. This step is dependent on selenium availability, as dietary selenium increases cellular glutathione peroxidase activity.
Catalytic cycle and glutathione oxidation
In simple terms: The enzyme turns hydrogen peroxide into water and converts glutathione into its oxidized form.
The catalytic cycle involves two molecules of GSH per H2O2 reduced. The first GSH molecule reduces the selenenic acid to a selenol, releasing water; the second GSH forms a mixed disulfide with the enzyme, which is then resolved to release oxidized glutathione (GSSG). The enzyme returns to its resting state. This ping-pong mechanism is characteristic of glutathione peroxidase activity. The resulting GSSG is recycled back to GSH by glutathione reductase at the expense of NADPH.
Substrate specificity and isoforms
In simple terms: Different versions of the enzyme prefer different targets, like hydrogen peroxide or lipid peroxides.
GPX1 reduces H2O2 and soluble hydroperoxides; GPX4 reduces complex lipid hydroperoxides in membranes, including phospholipid hydroperoxides and cholesterol hydroperoxides. GPX3 is secreted and acts in plasma. GPX2 is found in the gastrointestinal tract. This diversity allows glutathione peroxidase activity to protect various cellular compartments. Overexpression of GPX4 modulates acetyl-CoA and lyso-PAF acetyltransferase activity, indicating a role beyond direct antioxidant defense.
Regulation by selenium and oxidative stress
In simple terms: The amount of selenium you eat and the level of oxidative stress can change how active the enzyme is.
Selenium is incorporated into selenoproteins as selenocysteine, and its availability directly affects glutathione peroxidase activity. In kidney transplant recipients, dietary selenium supplementation increased cellular glutathione peroxidase activity and reduced susceptibility to lipid peroxidation. Physical activity and gender also influence plasma glutathione peroxidase levels, with differences observed between men and women. In smokers, physical activity was not associated with plasma glutathione peroxidase levels, suggesting that smoking may override exercise-induced changes.
Extracellular vesicle-mediated signaling
In simple terms: Exercise can make cells release tiny packages containing the enzyme that help blood vessels grow.
Exercise training stimulates the release of extracellular vesicles enriched in GPX1, which promote angiogenesis. This indicates that glutathione peroxidase activity can act in a paracrine manner to influence vascular biology. Additionally, preconditioning exercise inhibits neuronal ferroptosis via skeletal muscle-derived exosomes regulating the miR-484/ACSL4 axis, a process that may involve glutathione peroxidase activity.
Key Genes Involved in GO:0004602 glutathione peroxidase activity
The following genes encode enzymes that exhibit glutathione peroxidase activity or directly regulate its function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| GPX1 | Cytosolic and mitochondrial glutathione peroxidase; reduces H2O2 and soluble hydroperoxides | Most abundant isoform; linked to cancer, cardiovascular disease, and exercise-induced extracellular vesicles |
| GPX2 | Gastrointestinal glutathione peroxidase; protects intestinal epithelium | Implicated in colorectal cancer and inflammatory bowel disease |
| GPX3 | Plasma glutathione peroxidase; secreted into blood | Biomarker for oxidative stress; influenced by gender and physical activity |
| GPX4 | Phospholipid hydroperoxide glutathione peroxidase; reduces membrane lipid peroxides | Critical for ferroptosis regulation; modulates acetyl-CoA and lyso-PAF acetyltransferase |
| GPX5 | Epididymal glutathione peroxidase; protects sperm | Male fertility and oxidative stress in reproductive tract |
| GPX6 | Olfactory epithelium glutathione peroxidase | Sensory function and antioxidant defense |
| GPX7 | Non-selenium glutathione peroxidase; endoplasmic reticulum | Protein folding and oxidative stress in cancer |
| GPX8 | Membrane-bound glutathione peroxidase; endoplasmic reticulum | Regulates ER redox and calcium signaling |
| GSS | Glutathione synthetase; synthesizes glutathione | Provides substrate for glutathione peroxidase activity |
| GSR | Glutathione reductase; recycles GSSG to GSH | Maintains reduced glutathione pool for peroxidase activity |
| SLC7A11 | Cystine/glutamate antiporter; supplies cysteine for GSH synthesis | Regulates ferroptosis and glutathione peroxidase activity |
| ACSL4 | Acyl-CoA synthetase long-chain family member 4; promotes lipid peroxidation | Target of miR-484; modulates ferroptosis and GPX4 function |
| NFE2L2 | Nrf2 transcription factor; regulates antioxidant response elements | Controls expression of GPX genes and glutathione synthesis |
| SEPHS2 | Selenophosphate synthetase 2; required for selenocysteine synthesis | Essential for selenoprotein GPX activity |
| SELENOP | Selenoprotein P; selenium transport | Delivers selenium for GPX synthesis |
| TXN | Thioredoxin; alternative antioxidant system | Cross-talk with glutathione peroxidase activity |
| PRDX6 | Peroxiredoxin 6; non-selenium peroxidase | Overlaps with non-selenium glutathione peroxidase activity |
How Is glutathione peroxidase activity Regulated?
Glutathione peroxidase activity is regulated at multiple levels. Transcriptional regulation via the Nrf2/ARE pathway controls expression of GPX1, GPX2, GPX4, and genes involved in glutathione synthesis in response to oxidative stress. Selenium availability post-transcriptionally regulates selenoprotein GPX expression through selenocysteine incorporation machinery, with dietary selenium increasing activity. Physical activity and gender influence plasma glutathione peroxidase levels, possibly through hormonal and metabolic factors. In smokers, physical activity did not correlate with plasma glutathione peroxidase levels, suggesting that cigarette smoke-derived oxidants may overwhelm or alter regulatory pathways. Exercise training induces release of GPX1-enriched extracellular vesicles, representing a systemic regulatory mechanism. Additionally, microRNAs such as miR-484 can modulate glutathione peroxidase activity indirectly by targeting ACSL4, affecting ferroptosis sensitivity.
glutathione peroxidase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| GPX1 | Cancer, cardiovascular disease, oxidative stress | GPX1 knockout and overexpression cell lines; exercise-induced extracellular vesicle studies |
| GPX4 | Ferroptosis, neurodegeneration, ischemia-reperfusion injury | GPX4 knockout and point-mutation models; miR-484/ACSL4 axis studies |
| GPX3 | Plasma oxidative stress biomarker; kidney transplant outcomes | GPX3 overexpression in plasma; selenium supplementation models |
| GPX2 | Colorectal cancer, inflammatory bowel disease | GPX2 knockout intestinal epithelial cells |
| ACSL4 | Ferroptosis regulation, brain ischemia | ACSL4 knockout and miR-484 mimic/inhibitor models |
Cancer and oxidative stress
Glutathione peroxidase activity protects cells from oxidative DNA damage and lipid peroxidation, and altered activity has been observed in various cancers. GPX1 and GPX2 polymorphisms have been associated with cancer risk, and GPX3 promoter hypermethylation is common in prostate cancer. In smokers, physical activity was not associated with plasma glutathione peroxidase levels, indicating that smoking-related oxidative stress may override protective effects. Dietary selenium increases cellular glutathione peroxidase activity and reduces lipid peroxidation susceptibility in kidney transplant recipients, a population at elevated cancer risk.
Neurodegeneration and ferroptosis
GPX4 is a key regulator of ferroptosis, an iron-dependent form of cell death characterized by lipid peroxidation. Preconditioning exercise inhibits neuronal ferroptosis and ameliorates brain ischemia damage via skeletal muscle-derived exosomes regulating the miR-484/ACSL4 axis, a pathway that intersects with glutathione peroxidase activity. Swim training increases glutathione peroxidase activity in the spinal cord of ALS mice and ameliorates hyperlocomotion, suggesting a protective role in motor neuron disease.
Cardiovascular and metabolic disease
Glutathione peroxidase activity in plasma and low-density lipoprotein is inversely associated with cardiovascular risk. Dietary selenium supplementation in kidney transplant recipients increased cellular glutathione peroxidase activity and reduced susceptibility of plasma and LDL to lipid peroxidation, a key step in atherogenesis. Exercise training stimulates release of GPX1-enriched extracellular vesicles that promote angiogenesis, linking glutathione peroxidase activity to vascular remodeling.
Kidney transplantation and selenium status
Kidney transplant recipients exhibit enhanced susceptibility to lipid peroxidation, which is reduced by dietary selenium supplementation that increases cellular glutathione peroxidase activity. This highlights the clinical relevance of glutathione peroxidase activity in transplant medicine and the potential for nutritional intervention.
From glutathione peroxidase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does GPX1 protect against oxidative stress-induced cell death? | GPX1 knockout and overexpression cell lines |
| How does GPX4 mutation affect ferroptosis sensitivity? | GPX4 point-mutation knock-in cells |
| What is the role of GPX3 in plasma antioxidant defense? | GPX3 tagged knock-in for secretion studies |
| Can selenium supplementation rescue glutathione peroxidase activity? | Dietary selenium intervention in kidney transplant recipients |
| Does exercise-induced GPX1 extracellular vesicle release promote angiogenesis? | Exercise training models with GPX1-enriched EV isolation |
| How does miR-484 regulate ACSL4 and ferroptosis via glutathione peroxidase activity? | miR-484 knockout and ACSL4 overexpression models |
How to Study the glutathione peroxidase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH-coupled spectrophotometric assay | Glutathione peroxidase enzymatic activity | Plasma and tissue activity quantification |
| RNA-seq / qPCR | GPX gene expression levels | Transcriptional regulation under oxidative stress |
| Western blot / proteomics | GPX protein abundance and modifications | Isoform-specific expression analysis |
| CRISPR knockout screens | Genes required for glutathione peroxidase activity | Functional genomics and ferroptosis regulators |
| Redox biosensors (HyPer, roGFP) | Real-time H2O2 and GSH/GSSG dynamics | Live-cell imaging of redox changes |
| Extracellular vesicle isolation and characterization | GPX1-enriched EV release | Exercise-induced angiogenesis studies |
| Lipid peroxidation assays (MDA, 4-HNE) | Oxidative lipid damage | Susceptibility to lipid peroxidation |
| Selenium status biomarkers | Selenium availability for GPX synthesis | Nutritional intervention studies |
Enzymatic activity assays
Glutathione peroxidase activity is commonly measured spectrophotometrically by coupling the reduction of H2O2 or organic hydroperoxides to the oxidation of NADPH via glutathione reductase. The decrease in NADPH absorbance at 340 nm is monitored. This method is used to quantify activity in plasma, erythrocytes, and tissue homogenates.
Gene expression and proteomics
RNA-seq and qPCR can measure GPX gene expression, while Western blotting and mass spectrometry quantify protein levels. Selenoprotein-specific proteomics can identify GPX isoforms and their post-translational modifications. These approaches are essential for linking glutathione peroxidase activity to disease states.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout screens can identify genes that modulate glutathione peroxidase activity and ferroptosis sensitivity. Focused libraries targeting GPX genes and related pathways enable high-throughput discovery of regulators. Bioinformatics analysis of screening data reveals enriched pathways and networks.
Imaging and redox biosensors
Genetically encoded redox biosensors (e.g., HyPer, roGFP) allow real-time imaging of H2O2 and glutathione redox state in live cells. These tools can visualize the impact of glutathione peroxidase activity on cellular redox dynamics and subcellular localization.
How CRISPR Can Be Used to Study GO:0004602 glutathione peroxidase activity
Knockout
CRISPR knockout of GPX1, GPX4, or other GPX genes eliminates glutathione peroxidase activity, leading to increased oxidative stress and lipid peroxidation. GPX4 knockout is lethal due to ferroptosis, making it a powerful model to study ferroptosis mechanisms and the miR-484/ACSL4 axis. GPX1 knockout cells show enhanced sensitivity to H2O2 and altered extracellular vesicle cargo.
Point Mutation
Point mutations in the catalytic selenocysteine (Sec) residue of GPX enzymes abolish activity, allowing dissection of enzyme-dependent versus independent functions. Knock-in of Sec-to-Cys mutations can reveal substrate specificity changes. Such models are valuable for studying the role of glutathione peroxidase activity in ferroptosis and cancer.
Knock-in
Knock-in of tagged GPX alleles (e.g., HA, FLAG, GFP) enables tracking of protein localization, secretion, and interaction partners. Tagged GPX3 knock-in models can monitor plasma secretion, while tagged GPX4 knock-in reveals membrane localization. These models are essential for understanding isoform-specific functions.
Overexpression
Overexpression of GPX1 or GPX4 increases glutathione peroxidase activity and protects cells from oxidative stress and ferroptosis. GPX4 overexpression modulates acetyl-CoA and lyso-PAF acetyltransferase activity, linking the enzyme to lipid mediator synthesis. Overexpression models are used to test sufficiency of glutathione peroxidase activity in disease rescue.
How EDITGENE Supports glutathione peroxidase activity Research
Researchers studying glutathione peroxidase activity-related genes often need to determine whether a candidate gene is causally involved in oxidative stress resistance, ferroptosis, or disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling functional validation of GPX genes and their regulators.
Contact EDITGENE today to design your custom CRISPR model for glutathione peroxidase activity research.
Frequently Asked Questions About glutathione peroxidase activity
What is glutathione peroxidase activity?
Glutathione peroxidase activity (GO:0004602) is the catalytic activity that reduces hydrogen peroxide to water using reduced glutathione as an electron donor, producing oxidized glutathione.
What genes are involved in glutathione peroxidase activity?
The main genes are GPX1, GPX2, GPX3, GPX4, GPX5, GPX6, GPX7, and GPX8, which encode selenium-dependent and selenium-independent glutathione peroxidase enzymes.
How is glutathione peroxidase activity measured?
It is commonly measured by a coupled spectrophotometric assay monitoring NADPH oxidation at 340 nm in the presence of glutathione reductase, H2O2, and reduced glutathione.
What is the role of GPX4 in ferroptosis?
GPX4 reduces lipid hydroperoxides in membranes; its loss leads to ferroptosis, an iron-dependent cell death. Preconditioning exercise inhibits neuronal ferroptosis via the miR-484/ACSL4 axis, which intersects with GPX4 function.
Does exercise affect glutathione peroxidase activity?
Yes, exercise training stimulates release of GPX1-enriched extracellular vesicles that promote angiogenesis, and swim training increases glutathione peroxidase activity in the spinal cord of ALS mice.
How does selenium influence glutathione peroxidase activity?
Dietary selenium increases cellular glutathione peroxidase activity by supporting selenocysteine incorporation into GPX enzymes, as shown in kidney transplant recipients.
What diseases are linked to glutathione peroxidase activity?
Altered activity is linked to cancer, cardiovascular disease, neurodegeneration, ferroptosis-related ischemia, and kidney transplant oxidative stress.
Can CRISPR be used to study glutathione peroxidase genes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise functional dissection of GPX genes in oxidative stress and disease.
What is the difference between selenium-dependent and non-selenium glutathione peroxidase activity?
Selenium-dependent isoforms (e.g., GPX1, GPX4) contain selenocysteine in their active site, while non-selenium isoforms (e.g., GPX7, PRDX6) use cysteine; both catalyze glutathione-dependent peroxide reduction.
How does physical activity affect plasma glutathione peroxidase levels in smokers?
A study found no association between physical activity and plasma glutathione peroxidase levels in smokers, suggesting smoking-related oxidative stress may mask exercise effects.
Conclusion
Glutathione peroxidase activity (GO:0004602) is a fundamental antioxidant molecular function that protects cells from oxidative damage by reducing hydrogen peroxide and lipid peroxides using glutathione. Its regulation by selenium, exercise, and gender, as well as its involvement in cancer, neurodegeneration, cardiovascular disease, and ferroptosis, underscores its broad biomedical importance. Advances in CRISPR-based models and functional genomics are accelerating the dissection of GPX gene functions and their therapeutic potential. EDITGENE's comprehensive services support researchers in generating precise cell models to study glutathione peroxidase activity and translate findings into clinical applications.
References
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- 2. Yimcharoen M et al.. 2019. Effects of ascorbic acid supplementation on oxidative stress markers in healthy women following a single bout of exercise.. J Int Soc Sports Nutr 16(1):2 PMID: 30665439
- 3. Rush JW et al.. 2003. Plasma glutathione peroxidase in healthy young adults: influence of gender and physical activity.. Clin Biochem 36(5):345-51 PMID: 12849865
- 4. Hussein O et al.. 1997. Dietary selenium increases cellular glutathione peroxidase activity and reduces the enhanced susceptibility to lipid peroxidation of plasma and low-density lipoprotein in kidney transplant recipients.. Transplantation 63(5):679-85 PMID: 9075838
- 5. Fliflet AM et al.. 2026. Exercise Training Stimulates the Release of Glutathione Peroxidase 1 (GPX1)-Enriched Extracellular Vesicles That Promote Angiogenesis.. FASEB J 40(12):e72052 PMID: 42313915
- 6. Sakamoto H et al.. 2002. Overexpression of phospholipid hydroperoxide glutathione peroxidase modulates acetyl-CoA, 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase activity.. J Biol Chem 277(52):50431-8 PMID: 12397078
- 7. Dzik KP et al.. 2021. Swim Training Ameliorates Hyperlocomotion of ALS Mice and Increases Glutathione Peroxidase Activity in the Spinal Cord.. Int J Mol Sci 22(21) PMID: 34769048
- 8. Huang M et al.. 2024. Preconditioning Exercise Inhibits Neuron Ferroptosis and Ameliorates Brain Ischemia Damage by Skeletal Muscle-Derived Exosomes via Regulating miR-484/ACSL4 Axis.. Antioxid Redox Signal 41(13-15):769-792 PMID: 38545792
