GO:0036130 prostaglandin H2 endoperoxidase reductase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0036130 describes the enzymatic activity that catalyzes the NADPH-dependent reduction of prostaglandin H2 (PGH2) to prostaglandin F2alpha (PGF2alpha), with NADP+ and H+ as co-products.
• This activity is a terminal step in the prostaglandin biosynthetic pathway, converting the unstable endoperoxide PGH2 into the stable bioactive prostaglandin PGF2alpha.
• The reaction is distinct from the cyclooxygenase and peroxidase activities of prostaglandin endoperoxide synthase, which can be differentially modified by proteolytic digestion and hydroperoxides.
• Prostaglandin D synthetase, which acts on the same substrate PGH2, has been purified from rat brain, illustrating the branching of PGH2 metabolism.
• Researchers study this activity using enzyme assays, CRISPR knockout and knock-in models, and targeted metabolomics to link genotype to prostaglandin profiles.
• Dysregulation of PGH2 reduction may contribute to diseases where prostaglandin F2alpha levels are altered, though specific disease associations require further experimental validation.
Description
Prostaglandin H2 endoperoxidase reductase activity (GO:0036130) is a molecular function that catalyzes the conversion of prostaglandin H2 (PGH2) to prostaglandin F2alpha (PGF2alpha) in the presence of NADPH, producing NADP+ and a proton. This reaction represents a terminal step in the prostaglandin biosynthetic cascade, where the unstable endoperoxide intermediate PGH2 is reduced to a stable, biologically active prostaglandin. The activity is distinguished from the cyclooxygenase and peroxidase reactions of prostaglandin endoperoxide synthase, which can be differentially affected by proteolytic digestion and hydroperoxides. Understanding this activity is important because prostaglandins regulate diverse physiological processes, including inflammation, smooth muscle contraction, and reproduction. The enzyme prostaglandin D synthetase, which also uses PGH2 as a substrate, has been purified from rat brain, highlighting the multiple metabolic fates of PGH2. Researchers investigating GO:0036130 aim to define its kinetic properties, identify the responsible enzymes, and explore its role in health and disease. This article provides a research-grade overview of the term, its mechanism, associated genes, and experimental approaches.
prostaglandin H2 endoperoxidase reductase activity At A Glance
| GO ID | GO:0036130 |
|---|---|
| GO term | prostaglandin H2 endoperoxidase reductase activity |
| Ontology | molecular_function |
| Synonym | PGH2 9,11-endoperoxidase; PGH2 9-,11-endoperoxide reductase |
| Definition | Catalysis of the reaction: prostaglandin F2alpha + NADP+ = prostaglandin H2 + NADPH + H+ |
| Major function | Reduction of prostaglandin H2 to prostaglandin F2alpha using NADPH |
| Reaction direction | Physiologically favors PGH2 reduction to PGF2alpha |
| Cofactor | NADPH/NADP+ |
| Pathway context | Prostaglandin biosynthesis, terminal step |
What Is GO:0036130?
In simple terms, GO:0036130 is the enzyme activity that turns prostaglandin H2 into prostaglandin F2alpha by adding electrons from NADPH. According to the QuickGO definition, it catalyzes the reaction: prostaglandin F2alpha + NADP+ = prostaglandin H2 + NADPH + H+. This means the reverse reaction reduces PGH2 to PGF2alpha while oxidizing NADPH to NADP+ and releasing a proton. The activity is also known by synonyms such as PGH2 9,11-endoperoxidase and PGH2 9-,11-endoperoxide reductase. It is a molecular function term in the Gene Ontology, distinct from other prostaglandin-metabolizing activities such as prostaglandin D synthase.
Why Is prostaglandin H2 endoperoxidase reductase activity Important in Cell Biology?
GO:0036130 is important because it defines a key enzymatic step that determines the balance between different prostaglandins, particularly the conversion of the unstable endoperoxide PGH2 into the stable and potent mediator PGF2alpha. This activity influences diverse physiological and pathological processes, including inflammation, vascular tone, and reproductive functions. Because the same substrate PGH2 can be channeled into multiple products by distinct enzymes such as prostaglandin D synthetase, understanding the regulation and specificity of PGH2 reduction is critical for interpreting prostaglandin biology. Moreover, the differential sensitivity of cyclooxygenase and peroxidase activities to proteolysis and hydroperoxides suggests that the reductase activity may be independently regulated, offering a potential target for therapeutic intervention. Researchers studying this term can use it to annotate gene products, design experiments, and link molecular function to disease phenotypes.
• Defines a terminal step in prostaglandin biosynthesis, converting PGH2 to PGF2alpha.
• Provides a molecular function annotation for enzymes with PGH2 reductase activity.
• Helps distinguish this activity from cyclooxygenase and peroxidase activities of prostaglandin endoperoxide synthase.
• Enables comparative studies with other PGH2-metabolizing enzymes such as prostaglandin D synthetase.
• Supports research on inflammation and smooth muscle contraction mediated by PGF2alpha.
• Facilitates the design of CRISPR knockout and knock-in models to test gene function.
• Aids in interpreting metabolomic data by linking enzyme activity to prostaglandin profiles.
• May reveal new therapeutic targets in diseases with altered prostaglandin levels.
• Provides a basis for enzyme kinetics and inhibitor studies.
• Connects molecular function to broader physiological and pathological processes.
Molecular Mechanism of prostaglandin H2 endoperoxidase reductase activity
Substrate recognition and binding
In simple terms: The enzyme must first grab prostaglandin H2 (PGH2) from the membrane environment.
PGH2 is an unstable endoperoxide intermediate produced by cyclooxygenase activity. The reductase enzyme binds PGH2, positioning its endoperoxide moiety for reduction. The specificity for PGH2 over other prostaglandins is a key feature, and the enzyme must discriminate among closely related substrates. This step is analogous to other PGH2-utilizing enzymes such as prostaglandin D synthetase, which also binds PGH2 but catalyzes a different reaction.
NADPH-dependent reduction
In simple terms: The enzyme uses NADPH to donate electrons to convert PGH2 into PGF2alpha.
The catalytic mechanism involves hydride transfer from NADPH to the endoperoxide, leading to cleavage of the peroxide bond and formation of the hydroxyl groups characteristic of PGF2alpha. The reaction produces NADP+ and a proton as co-products, as defined by the GO term. This reductive step is distinct from the peroxidase activity of prostaglandin endoperoxide synthase, which can be differentially modified by proteolytic digestion and hydroperoxides.
Product release and isomer specificity
In simple terms: After the reaction, the enzyme releases PGF2alpha, which can then act on its receptors.
The product PGF2alpha is a stable prostaglandin that exerts biological effects through specific receptors. The stereochemistry of the reduction determines whether PGF2alpha or other isomers are formed. The enzyme must release the product efficiently to allow turnover. This step is critical for regulating the local concentration of PGF2alpha. The existence of multiple PGH2-metabolizing enzymes, such as prostaglandin D synthetase, underscores the importance of product specificity in prostaglandin signaling.
Regulation by hydroperoxides and proteolysis
In simple terms: The activity can be turned up or down by cellular conditions like oxidative stress or protein cleavage.
Studies on prostaglandin endoperoxide synthase have shown that its cyclooxygenase and peroxidase activities can be differentially modified by proteolytic digestion and hydroperoxides. This suggests that the reductase activity of GO:0036130 may also be subject to similar regulation. Hydroperoxides can influence the redox state of the enzyme, while proteolysis may remove regulatory domains. Understanding these regulatory mechanisms is essential for predicting how the activity responds to cellular stress.
Key Genes Involved in GO:0036130 prostaglandin H2 endoperoxidase reductase activity
The following genes and proteins are directly or indirectly involved in prostaglandin H2 endoperoxidase reductase activity or related prostaglandin pathways, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PTGS1 | Cyclooxygenase-1, produces PGH2 from arachidonic acid | Upstream of GO:0036130; target for knockout studies |
| PTGS2 | Cyclooxygenase-2, inducible PGH2 production | Inflammation models; CRISPR knockout to assess PGH2 supply |
| PTGFS | Prostaglandin F synthase, catalyzes PGH2 to PGF2alpha | Direct candidate for GO:0036130 activity |
| AKR1B1 | Aldo-keto reductase, may reduce PGH2 | Potential off-target or alternative enzyme |
| AKR1C3 | Aldo-keto reductase, prostaglandin metabolism | Candidate for PGH2 reduction |
| PTGDS | Prostaglandin D synthase, converts PGH2 to PGD2 | Competing enzyme for PGH2 |
| PTGES | Prostaglandin E synthase, converts PGH2 to PGE2 | Competing pathway |
| TBXAS1 | Thromboxane A synthase, converts PGH2 to TXA2 | Competing pathway |
| PGFS | Prostaglandin F synthase (alternative name) | Direct enzyme for GO:0036130 |
| CBR1 | Carbonyl reductase 1, may reduce prostaglandins | Potential reductase activity |
| PTGFR | Prostaglandin F2alpha receptor | Downstream signaling; knockout models |
| NADPH | Cofactor for the reduction | Not a gene but essential cofactor |
| NQO1 | Quinone reductase, possible redox partner | Indirect role in NADPH balance |
| G6PD | Glucose-6-phosphate dehydrogenase, generates NADPH | Supports cofactor supply |
| IDH1 | Isocitrate dehydrogenase, NADPH production | Cofactor supply |
| ME1 | Malic enzyme, NADPH production | Cofactor supply |
| SLC2A1 | Glucose transporter, fuels NADPH production | Metabolic context |
| HMOX1 | Heme oxygenase, oxidative stress response | May influence hydroperoxide levels |
How Is prostaglandin H2 endoperoxidase reductase activity Regulated?
The activity of prostaglandin H2 endoperoxidase reductase (GO:0036130) is likely regulated at multiple levels. The availability of the substrate PGH2 is controlled by upstream cyclooxygenases (PTGS1/PTGS2), which can be differentially modified by proteolytic digestion and hydroperoxides. The redox state of the cell, particularly the NADPH/NADP+ ratio, directly affects the reductase reaction. Hydroperoxides can modulate the activity of prostaglandin endoperoxide synthase, suggesting that oxidative stress may influence PGH2 reduction. Additionally, the expression of the responsible enzyme(s) may be regulated transcriptionally by inflammatory mediators. Competing enzymes such as prostaglandin D synthetase can divert PGH2 to other products, indirectly affecting the flux through GO:0036130. Post-translational modifications, including proteolysis, may also alter activity. Further research is needed to fully elucidate the regulatory mechanisms specific to this activity.
prostaglandin H2 endoperoxidase reductase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PTGFS | Inflammation, reproductive disorders | Knockout mice, cell lines |
| PTGS2 | Inflammation, cancer | Conditional knockout, overexpression |
| PTGDS | Allergic diseases, sleep disorders | Knockout, knock-in |
| PTGFR | Ocular hypertension, preterm labor | Point mutation, knockout |
| AKR1C3 | Cancer, inflammation | CRISPR knockout, inhibitor studies |
Inflammation and pain
Prostaglandin F2alpha, the product of GO:0036130, is a potent mediator of inflammation and pain. Elevated PGF2alpha levels have been associated with inflammatory conditions. The activity of the reductase may therefore contribute to inflammatory diseases. Studies on prostaglandin endoperoxide synthase have shown that its activities can be differentially modified by hydroperoxides, which are elevated in inflammation. Targeting the reductase activity could provide a novel anti-inflammatory strategy.
Reproductive disorders
PGF2alpha plays a critical role in uterine contraction and luteolysis. Dysregulation of its synthesis, including the step catalyzed by GO:0036130, may contribute to reproductive disorders such as dysmenorrhea or preterm labor. The enzyme prostaglandin D synthetase, which also uses PGH2, has been purified from rat brain, indicating the importance of PGH2 metabolism in different tissues. However, direct evidence linking GO:0036130 to reproductive diseases is still limited.
Cardiovascular disease
Prostaglandins regulate vascular tone and platelet aggregation. PGF2alpha can act as a vasoconstrictor. Altered PGH2 reduction may affect cardiovascular homeostasis. The differential modification of cyclooxygenase and peroxidase activities by proteolysis and hydroperoxides suggests that the reductase step could be independently affected in cardiovascular pathology. Further studies are needed to establish a causal role.
From prostaglandin H2 endoperoxidase reductase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PTGFS reduce PGF2alpha levels? | CRISPR knockout cell line |
| Does a point mutation in the active site abolish reductase activity? | Point mutation knock-in |
| Can tagged PTGFS be used to study localization? | Tagged knock-in (e.g., GFP) |
| Does overexpression of PTGFS increase PGF2alpha? | Overexpression stable cell line |
| Which genes regulate PGH2 flux? | CRISPR library screening |
| What is the metabolic impact of PTGFS knockout? | Metabolomics with KO cells |
How to Study the prostaglandin H2 endoperoxidase reductase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme assay (NADPH oxidation) | Reductase activity | Kinetic studies, inhibitor screening |
| LC-MS/MS | PGF2alpha and other prostaglandins | Metabolomic profiling |
| CRISPR knockout screen | Genes affecting PGF2alpha levels | Discovery of novel regulators |
| Western blot | Protein expression | Validation of knockout/overexpression |
| Immunofluorescence | Subcellular localization | Cellular component studies |
| RNA-seq | Transcriptional changes | Pathway analysis |
| Proteomics | Protein interactions | Interactome mapping |
Enzyme activity assays
Direct measurement of GO:0036130 activity can be performed using purified enzyme or cell lysates with PGH2 as substrate and NADPH as cofactor. The reaction can be monitored by following NADPH oxidation spectrophotometrically or by detecting PGF2alpha formation using mass spectrometry. Such assays are essential for kinetic characterization and inhibitor testing. The differential modification of cyclooxygenase and peroxidase activities by proteolysis and hydroperoxides highlights the need for specific assays that distinguish the reductase step.
CRISPR-based genetic screens
CRISPR knockout libraries can be used to identify genes required for PGH2 reduction. Cells are infected with a library of guide RNAs, and those with altered PGF2alpha production are selected. This approach can uncover novel enzymes or regulators of GO:0036130. The method is powerful for unbiased discovery and can be combined with metabolomic readouts.
Targeted metabolomics
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) can quantify prostaglandins including PGF2alpha and PGH2 (though PGH2 is unstable). By comparing wild-type and mutant cells, researchers can infer changes in GO:0036130 flux. This method is highly sensitive and can be used to validate findings from genetic screens.
Proteomics and interactomics
Affinity purification coupled with mass spectrometry can identify proteins that interact with the reductase enzyme. This helps define the cellular component and potential regulatory partners. For example, prostaglandin D synthetase was purified from rat brain using classical biochemical methods; modern proteomics can achieve similar goals more rapidly.
How CRISPR Can Be Used to Study GO:0036130 prostaglandin H2 endoperoxidase reductase activity
Knockout
CRISPR knockout of candidate genes such as PTGFS or AKR1C3 can abolish GO:0036130 activity, leading to reduced PGF2alpha levels. This approach is used to establish causality between a gene and the enzymatic activity. Knockout cell lines can be generated in relevant cell types, such as fibroblasts or macrophages, and validated by sequencing and western blot. The effect on prostaglandin profiles can be measured by metabolomics.
Point Mutation
Introducing specific point mutations in the active site of the candidate enzyme can help identify catalytic residues essential for GO:0036130. For example, mutating a predicted NADPH-binding residue would impair reduction. This approach provides mechanistic insights beyond simple knockout. Point mutant cell lines can be compared to wild-type for activity and product formation.
Knock-in
Knock-in of a tagged version of the enzyme (e.g., GFP or FLAG) allows visualization and affinity purification. This is useful for studying subcellular localization and protein interactions. Knock-in of disease-associated mutations can also model human variants. The tagged enzyme should retain activity, which can be confirmed by enzyme assays.
Overexpression
Overexpression of the candidate enzyme can increase GO:0036130 flux and PGF2alpha production. This is useful for gain-of-function studies and for producing sufficient protein for structural studies. Overexpression models can also be used to test whether increased activity exacerbates disease phenotypes in cell-based assays.
How EDITGENE Supports prostaglandin H2 endoperoxidase reductase activity Research
Researchers studying prostaglandin H2 endoperoxidase reductase activity-related genes often need to determine whether a candidate gene is causally involved in the enzymatic reaction, how mutations affect activity, and what downstream phenotypes result. EDITGENE provides a comprehensive suite of CRISPR services to address these questions, from knockout to precise point mutations, enabling rigorous functional validation.
Contact EDITGENE today to design your custom CRISPR model for prostaglandin H2 endoperoxidase reductase activity research.
Frequently Asked Questions About prostaglandin H2 endoperoxidase reductase activity
What is prostaglandin H2 endoperoxidase reductase activity?
It is an enzymatic activity (GO:0036130) that catalyzes the reduction of prostaglandin H2 to prostaglandin F2alpha using NADPH, producing NADP+ and a proton.
What genes are involved in prostaglandin H2 endoperoxidase reductase activity?
Candidate genes include PTGFS, AKR1C3, and other aldo-keto reductases, though the exact enzyme(s) may vary by tissue. Upstream genes PTGS1 and PTGS2 supply the substrate PGH2.
What is the reaction catalyzed by GO:0036130?
The reaction is: prostaglandin F2alpha + NADP+ = prostaglandin H2 + NADPH + H+. Physiologically, it reduces PGH2 to PGF2alpha.
How is prostaglandin H2 endoperoxidase reductase activity regulated?
It is likely regulated by substrate availability, NADPH/NADP+ ratio, hydroperoxides, and proteolysis, as suggested by studies on prostaglandin endoperoxide synthase.
What diseases are associated with prostaglandin H2 endoperoxidase reductase activity?
Altered activity may contribute to inflammation, reproductive disorders, and cardiovascular disease, but direct evidence is still emerging.
How can I study prostaglandin H2 endoperoxidase reductase activity in the lab?
You can use enzyme assays, LC-MS/MS metabolomics, and CRISPR knockout or knock-in models to manipulate candidate genes and measure effects.
What is the difference between prostaglandin H2 endoperoxidase reductase and prostaglandin D synthetase?
Both use PGH2 as substrate, but prostaglandin D synthetase produces PGD2, while GO:0036130 produces PGF2alpha. Prostaglandin D synthetase has been purified from rat brain.
Can CRISPR be used to study GO:0036130?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be used to test the role of specific genes in this activity.
What cofactors are required for prostaglandin H2 endoperoxidase reductase activity?
NADPH is required as the electron donor, and the reaction produces NADP+ and H+.
Where can I find authoritative information about GO:0036130?
The QuickGO database provides the official definition and synonyms. Primary literature such as Raz et al. (1990) and Shimizu et al. (1979) provide experimental context.
Conclusion
GO:0036130, prostaglandin H2 endoperoxidase reductase activity, defines a critical enzymatic step in prostaglandin biosynthesis that converts PGH2 to PGF2alpha. Despite its importance, the specific enzymes and regulatory mechanisms remain areas of active research. The differential modification of cyclooxygenase and peroxidase activities by proteolysis and hydroperoxides and the existence of competing enzymes like prostaglandin D synthetase highlight the complexity of PGH2 metabolism. Researchers can leverage CRISPR models and metabolomic approaches to uncover the roles of this activity in health and disease. EDITGENE offers comprehensive services to support such investigations.
References
- 1. Raz A et al.. 1990. Differential modification of cyclo-oxygenase and peroxidase activities of prostaglandin endoperoxidase synthase by proteolytic digestion and hydroperoxides.. Biochem J 269(3):603-7 PMID: 2117918
- 2. Shimizu T et al.. 1979. Purification and properties of prostaglandin D synthetase from rat brain.. J Biol Chem 254(12):5222-8 PMID: 109431
