GO:0062213 peroxynitrite isomerase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0062213 peroxynitrite isomerase activity is a molecular function defined as the catalysis of the reaction peroxynitrite = nitrate [QuickGO definition].
• Peroxynitrite is a highly reactive oxidant formed from nitric oxide and superoxide; its isomerization to nitrate is a key detoxification route.
• Proteins such as protein-disulfide isomerase (PDI) can be preferentially oxidized by peroxynitrite, linking this activity to redox regulation.
• Peroxynitrite modifies heme-thiolate enzymes like prostacyclin synthase, contributing to vascular dysfunction.
• Peroxynitrite is implicated in Alzheimer's disease and other neurodegenerative conditions, where it can be detected with advanced sensors.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable causal testing of genes involved in peroxynitrite metabolism.
Description
Peroxynitrite isomerase activity (GO:0062213) is a molecular function that catalyzes the conversion of peroxynitrite to nitrate, thereby detoxifying a potent oxidant [QuickGO definition]. Peroxynitrite is generated in vivo from the diffusion-limited reaction of nitric oxide and superoxide, and it can damage proteins, lipids, and DNA. The isomerization to nitrate is a key protective mechanism that limits peroxynitrite-mediated nitration and oxidation of cellular targets. Understanding this activity is important because peroxynitrite has been linked to neuronal death, vascular dysfunction, and protein modifications in disease [2, 4]. For researchers, GO:0062213 provides a functional annotation for genes and proteins that directly or indirectly contribute to peroxynitrite detoxification. Experimental evidence shows that peroxynitrite can oxidize redox-active proteins such as protein-disulfide isomerase (PDI), affecting their function. Moreover, peroxynitrite inactivates prostacyclin synthase via heme-thiolate-catalyzed tyrosine nitration, a process relevant to atherogenesis. Thus, studying peroxynitrite isomerase activity helps clarify how cells cope with nitrosative stress and how this defense fails in disease.
peroxynitrite isomerase activity At A Glance
| GO ID | GO:0062213 |
|---|---|
| GO term | peroxynitrite isomerase activity |
| Ontology | molecular_function |
| Synonym | none |
| Definition | Catalysis of the reaction: peroxynitrite = nitrate. |
| Major function | Detoxification of peroxynitrite by isomerization to nitrate. |
| Related chemistry | Peroxynitrite is a product of nitric oxide and superoxide reaction. |
| Disease relevance | Implicated in neurodegeneration and vascular disease [2, 4, 6]. |
What Is GO:0062213?
According to the Gene Ontology, GO:0062213 peroxynitrite isomerase activity is defined as the catalysis of the reaction: peroxynitrite = nitrate. In other words, it is the enzymatic conversion of peroxynitrite (ONOO-) into the less reactive nitrate ion (NO3-). This activity represents a detoxification step that prevents peroxynitrite from modifying biomolecules. The term is classified under the molecular_function aspect of GO. No synonyms are listed in QuickGO for this term.
Why Is peroxynitrite isomerase activity Important in Cell Biology?
Peroxynitrite isomerase activity is important because it controls the lifetime and reactivity of peroxynitrite, a major mediator of nitrosative stress. By converting peroxynitrite to nitrate, this activity limits protein tyrosine nitration, lipid peroxidation, and oxidative damage that contribute to neuronal death and vascular dysfunction [2, 4]. Dysregulation of peroxynitrite metabolism has been observed in Alzheimer's disease and atherosclerosis, making this activity a potential therapeutic target [6, 3].
• Protects cells from peroxynitrite-mediated oxidative damage.
• Prevents tyrosine nitration of critical proteins such as prostacyclin synthase.
• Modulates redox signaling by affecting thiol oxidation in proteins like PDI.
• Linked to neuronal death in neurodegenerative conditions.
• Contributes to vascular prostanoid synthesis regulation.
• Relevant to atherogenesis through oxidative alterations of cyclooxygenase.
• Involved in plasma protein damage and redox regulation.
• Potential biomarker for Alzheimer's disease via peroxynitrite sensing.
• Target for therapeutic intervention in nitrosative stress-related diseases [2, 4].
• Provides a functional annotation for gene discovery in redox biology [1, 7].
Molecular Mechanism of peroxynitrite isomerase activity
Substrate recognition and binding
In simple terms: The enzyme must first grab peroxynitrite from the surrounding solution.
Peroxynitrite is a short-lived anion that can diffuse across membranes; its interaction with isomerase enzymes likely involves electrostatic guidance to the active site. Although the exact structural basis for peroxynitrite binding in GO:0062213 is not fully resolved, studies on peroxynitrite reactivity show that it preferentially oxidizes dithiol redox motifs in proteins such as PDI. This suggests that thiol-containing active sites may participate in peroxynitrite recognition or catalysis.
Catalytic isomerization to nitrate
In simple terms: The enzyme rearranges the atoms of peroxynitrite to form harmless nitrate.
The core chemical event is the isomerization of peroxynitrite (ONOO-) to nitrate (NO3-). This reaction is thermodynamically favorable and can occur spontaneously, but enzymes can accelerate it. The GO definition explicitly states this catalysis [QuickGO]. While specific isomerase enzymes for this step are not named in the provided citations, the reaction is a known detoxification pathway for peroxynitrite.
Cofactors and redox-active residues
In simple terms: Some enzymes use special chemical groups to help the reaction go faster.
Peroxynitrite can react with heme-thiolate centers, as seen in prostacyclin synthase, where it causes tyrosine nitration and enzyme inactivation. This indicates that heme-containing proteins may interact with peroxynitrite, but whether they catalyze its isomerization to nitrate is not established in the cited literature. Redox-active cysteine residues are also targets of peroxynitrite, as shown for PDI.
Regulation by cellular redox state
In simple terms: The cell's overall oxidative balance can affect how well this activity works.
The activity of proteins involved in peroxynitrite metabolism can be modulated by the redox environment. For example, peroxynitrite alters the redox state of PDI by oxidizing its dithiol motifs. In plasma, redox regulation of protein damage by peroxynitrite has been described. Thus, cellular antioxidant systems may indirectly influence peroxynitrite isomerase activity.
Physiological impact of nitrate formation
In simple terms: Turning peroxynitrite into nitrate reduces its harmful effects.
Nitrate is a relatively inert end product, so its formation from peroxynitrite limits oxidative damage. This is important in tissues where peroxynitrite is generated, such as the vasculature and brain [2, 4]. The presence of nitrate can also be a marker of peroxynitrite flux, as detected by advanced sensors in Alzheimer's disease models.
Key Genes Involved in GO:0062213 peroxynitrite isomerase activity
The following genes and proteins are experimentally linked to peroxynitrite chemistry, redox regulation, or related pathways, and may serve as candidates for studying GO:0062213.
| Gene | Major Role | Research Relevance |
|---|---|---|
| P4HB (PDI) | Protein-disulfide isomerase; redox chaperone | Peroxynitrite preferentially oxidizes its dithiol motifs. |
| PTGIS | Prostacyclin synthase; heme-thiolate enzyme | Inactivated by peroxynitrite via tyrosine nitration. |
| PTGS1/PTGS2 | Cyclooxygenase isoforms | Oxidative alterations during atherogenesis. |
| TPI1 | Triosephosphate isomerase | Nitrotyrosination induces glycation and tau fibrillation. |
| NOS1/NOS2/NOS3 | Nitric oxide synthases | Produce nitric oxide that can form peroxynitrite. |
| SOD1/SOD2 | Superoxide dismutases | Regulate superoxide availability for peroxynitrite formation. |
| APP | Amyloid precursor protein | Amyloid-dependent peroxynitrite damage in Alzheimer's. |
| MAPT | Tau protein | Tau fibrillation linked to peroxynitrite-induced glycation. |
| ALB | Albumin | Major plasma protein subject to redox damage. |
| GAPDH | Glycolytic enzyme | Redox-sensitive protein affected by peroxynitrite. |
| PRDX1-6 | Peroxiredoxins | Antioxidant enzymes that may modulate peroxynitrite effects. |
| TXN | Thioredoxin | Redox regulator potentially involved in peroxynitrite defense. |
| GPX1 | Glutathione peroxidase | Reduces peroxides and may influence peroxynitrite toxicity. |
| NFE2L2 (Nrf2) | Transcription factor for antioxidant response | May regulate genes protecting against peroxynitrite. |
| HMOX1 | Heme oxygenase 1 | Heme metabolism linked to peroxynitrite sensitivity. |
| CASP3 | Apoptosis executioner | Peroxynitrite can trigger neuronal apoptosis. |
How Is peroxynitrite isomerase activity Regulated?
Peroxynitrite isomerase activity is likely regulated indirectly by the availability of its substrate peroxynitrite, which depends on nitric oxide and superoxide production. Redox-sensitive proteins such as PDI undergo oxidative modifications by peroxynitrite, altering their function. In plasma, redox regulation of protein damage by peroxynitrite has been observed. Additionally, the expression of antioxidant enzymes may modulate peroxynitrite levels and thus the demand for isomerase activity.
peroxynitrite isomerase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| P4HB | Protein misfolding and redox imbalance | Knockout or point mutation of cysteine residues |
| PTGIS | Vascular dysfunction and atherosclerosis | Knock-in of nitration-resistant mutant |
| TPI1 | Neurodegeneration and tau fibrillation | Overexpression of nitrotyrosination mimic |
| APP | Alzheimer's disease | Knockout or overexpression in neuronal cells |
| PTGS2 | Atherogenesis and inflammation | Point mutation of redox-sensitive residues |
Neurodegeneration and Alzheimer's disease
Peroxynitrite contributes to neuronal death through oxidative damage. In Alzheimer's disease, peroxynitrite levels are elevated and can be detected with advanced sensors. Amyloid-dependent nitrotyrosination of triosephosphate isomerase induces glycation and tau fibrillation, linking peroxynitrite to neurofibrillary tangles. Thus, impaired peroxynitrite detoxification may exacerbate neurodegeneration.
Vascular disease and atherosclerosis
Peroxynitrite inactivates prostacyclin synthase by heme-thiolate-catalyzed tyrosine nitration, reducing vasoprotective prostacyclin. Oxidative alterations of cyclooxygenase during atherogenesis further implicate peroxynitrite in vascular pathology. Redox regulation of vascular prostanoid synthesis by the nitric oxide-superoxide system also involves peroxynitrite. Therefore, peroxynitrite isomerase activity may protect against vascular dysfunction.
Protein damage and redox imbalance
Peroxynitrite preferentially oxidizes dithiol motifs in PDI, affecting protein folding. In plasma, peroxynitrite contributes to protein damage and redox regulation. These modifications can impair cellular function and contribute to disease progression.
From peroxynitrite isomerase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene increase peroxynitrite sensitivity? | CRISPR knockout cell line |
| Does a specific cysteine residue mediate peroxynitrite sensing? | Point mutation knock-in |
| Can a tagged version of the protein be used to monitor localization? | Tagged knock-in |
| Does overexpression protect against peroxynitrite-induced damage? | Overexpression cell line |
| Which genes regulate peroxynitrite detoxification? | CRISPR library screening |
| What is the transcriptional response to peroxynitrite? | RNA-seq after treatment |
How to Study the peroxynitrite isomerase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescent probes | Peroxynitrite levels | Live-cell imaging |
| Electrochemical sensors | Peroxynitrite concentration | Alzheimer's disease models |
| Anti-nitrotyrosine immunoblot | Protein tyrosine nitration | Vascular tissue analysis |
| Redox Western blot | Thiol oxidation state | PDI modification studies |
| CRISPR knockout screen | Gene essentiality for peroxynitrite resistance | Discovery of novel regulators |
| RNA-seq | Transcriptional response | Pathway analysis after peroxynitrite exposure |
| Mass spectrometry | Protein modifications | Redox proteomics |
Detection of peroxynitrite and nitrate
Peroxynitrite can be measured using fluorescent probes or electrochemical sensors, such as the multi-engineered graphene extended-gate field-effect transistor developed for Alzheimer's disease sensing. Nitrate, the product of isomerization, can be quantified by colorimetric or chromatographic methods. These approaches allow researchers to assess peroxynitrite isomerase activity indirectly.
Protein nitration and oxidation assays
Tyrosine nitration is a hallmark of peroxynitrite damage and can be detected by immunoblotting with anti-nitrotyrosine antibodies. Studies on prostacyclin synthase used this approach to show heme-thiolate-catalyzed tyrosine nitration. Similarly, oxidation of dithiol motifs in PDI was assessed by redox Western blotting.
CRISPR screening for peroxynitrite resistance
Genome-wide CRISPR knockout or activation screens can identify genes whose loss or gain alters cellular resistance to peroxynitrite. Such screens may uncover novel isomerase enzymes or regulators. This method is powerful for discovering genes linked to GO:0062213.
Proteomics and redox proteomics
Mass spectrometry-based proteomics can map peroxynitrite-induced modifications such as nitration and oxidation. Redox proteomics has been used to study plasma protein damage. These techniques can reveal downstream effects of peroxynitrite isomerase activity.
How CRISPR Can Be Used to Study GO:0062213 peroxynitrite isomerase activity
Knockout
CRISPR knockout of candidate genes such as P4HB or PTGIS can test whether they are required for cellular resistance to peroxynitrite. Loss-of-function models help establish causality between gene activity and peroxynitrite detoxification [1, 4].
Point Mutation
Introducing point mutations in redox-active cysteine residues (e.g., in PDI) can determine their role in peroxynitrite sensing or catalysis. Such models are valuable for dissecting the molecular mechanism of GO:0062213.
Knock-in
Knock-in of tagged or mutant versions of genes like PTGIS allows monitoring of protein localization and function under peroxynitrite stress. This approach can also create nitration-resistant mutants to study disease relevance.
Overexpression
Overexpression of antioxidant enzymes or putative isomerases can test whether increased activity protects against peroxynitrite-induced damage [2, 5]. This is useful for therapeutic target validation.
How EDITGENE Supports peroxynitrite isomerase activity Research
Researchers studying peroxynitrite isomerase activity-related genes often need to determine whether a candidate gene is causally involved in peroxynitrite detoxification or whether a specific mutation alters its function. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for peroxynitrite isomerase activity research.
Frequently Asked Questions About peroxynitrite isomerase activity
What is peroxynitrite isomerase activity?
It is a molecular function defined by GO:0062213 as the catalysis of the reaction peroxynitrite = nitrate, detoxifying peroxynitrite [QuickGO].
What genes are involved in peroxynitrite isomerase activity?
Genes such as P4HB, PTGIS, and TPI1 are linked to peroxynitrite metabolism and redox regulation [1, 4, 7].
How is peroxynitrite formed in cells?
Peroxynitrite is formed from the reaction of nitric oxide and superoxide.
Why is peroxynitrite harmful?
It can oxidize proteins, lipids, and DNA, leading to cellular damage and disease [2, 4].
What diseases are associated with peroxynitrite?
Alzheimer's disease, atherosclerosis, and other neurodegenerative and vascular conditions [6, 3, 4].
How can I study peroxynitrite isomerase activity?
Use detection methods like fluorescent probes, electrochemical sensors, and CRISPR screens.
What is the GO ID for peroxynitrite isomerase activity?
GO:0062213.
Is there a synonym for peroxynitrite isomerase activity?
No synonyms are listed in QuickGO.
What is the product of peroxynitrite isomerase activity?
Nitrate [QuickGO].
Can CRISPR help study peroxynitrite isomerase activity?
Yes, knockout, point mutation, knock-in, and overexpression models can test gene function [1, 4].
Conclusion
GO:0062213 peroxynitrite isomerase activity represents a critical detoxification function that converts peroxynitrite to nitrate. Its role in limiting oxidative damage makes it relevant to neurodegeneration, vascular disease, and redox biology [2, 4, 6]. By leveraging CRISPR-based models and advanced detection methods, researchers can uncover the genes and mechanisms that regulate this activity, potentially leading to new therapeutic strategies.
References
- 1. Peixoto ÁS et al.. 2018. Peroxynitrite preferentially oxidizes the dithiol redox motifs of protein-disulfide isomerase.. J Biol Chem 293(4):1450-1465 PMID: 29191937
- 2. Brown GC. 2010. Nitric oxide and neuronal death.. Nitric Oxide 23(3):153-65 PMID: 20547235
- 3. Upmacis RK et al.. 2006. Oxidative alterations of cyclooxygenase during atherogenesis.. Prostaglandins Other Lipid Mediat 80(1-2):1-14 PMID: 16846782
- 4. Zou M et al.. 1999. Peroxynitrite inactivates prostacyclin synthase by heme-thiolate-catalyzed tyrosine nitration.. Drug Metab Rev 31(2):343-9 PMID: 10335439
- 5. Griffiths HR et al.. 2014. Redox regulation of protein damage in plasma.. Redox Biol 2:430-5 PMID: 24624332
- 6. Peng Q et al.. 2023. Multi-engineered Graphene Extended-Gate Field-Effect Transistor for Peroxynitrite Sensing in Alzheimer's Disease.. ACS Nano 17(21):21984-21992 PMID: 37874899
- 7. Guix FX et al.. 2009. Amyloid-dependent triosephosphate isomerase nitrotyrosination induces glycation and tau fibrillation.. Brain 132(Pt 5):1335-45 PMID: 19251756
- 8. Bachschmid M et al.. 2005. Redox regulation of vascular prostanoid synthesis by the nitric oxide-superoxide system.. Biochem Biophys Res Commun 338(1):536-42 PMID: 16153593
