GO:0032542 sulfiredoxin activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0032542 (sulfiredoxin activity) catalyzes the ATP-dependent reduction of hyperoxidized peroxiredoxins, restoring their peroxidase function.
• The reaction consumes ATP and two thiol equivalents to convert peroxiredoxin-(S-hydroxy-S-oxocysteine) back to peroxiredoxin-(S-hydroxycysteine).
• Sulfiredoxin (SRXN1/SRX) is the principal enzyme carrying this activity in mammalian cells.
• SRXN1 expression is transcriptionally controlled by Nrf2 and AP-1, linking it to oxidative stress responses.
• Dysregulated sulfiredoxin activity is implicated in cancer, liver fibrosis, pancreatic disease, and circadian mitochondrial metabolism [2,3,1,8].
• CRISPR knockout, point-mutation, knock-in, and overexpression models are key tools for dissecting SRXN1 function in disease [2,3].
Description
Sulfiredoxin activity (GO:0032542) is a molecular function that reverses the hyperoxidation of peroxiredoxins, a modification that otherwise inactivates these antioxidant enzymes. Peroxiredoxins are abundant thiol peroxidases that detoxify hydrogen peroxide and peroxynitrite; under oxidative stress, their catalytic cysteine can be overoxidized to a sulfinic acid form, and sulfiredoxin catalyzes the ATP-dependent reduction of this sulfinic acid back to a sulfenic acid, restoring peroxidase activity. This function is essential for maintaining cellular redox homeostasis and for allowing peroxiredoxins to cycle between active and inactive states. The enzyme responsible, sulfiredoxin-1 (SRXN1, also known as SRX), is a small protein conserved from yeast to humans and is itself regulated by oxidative stress-responsive transcription factors such as Nrf2 and AP-1. Because peroxiredoxins are central to hydrogen peroxide signaling and antioxidant defense, sulfiredoxin activity influences diverse processes including cell proliferation, apoptosis, and stress resistance. In recent years, sulfiredoxin has been linked to cancer progression, liver fibrosis, pancreatic redox signaling, and circadian rhythms, making it a subject of intense research interest [2,3,1,8]. Understanding GO:0032542 therefore provides a mechanistic entry point into redox regulation in health and disease.
sulfiredoxin activity At A Glance
| GO ID | GO:0032542 |
|---|---|
| GO term | sulfiredoxin activity |
| Ontology | molecular_function |
| Synonym | peroxiredoxin-(S-hydroxy-S-oxocysteine) reductase activity; peroxiredoxin-(S-hydroxy-S-oxocysteine):thiol oxidoreductase [ATP-hydrolysing; peroxiredoxin-(S-hydroxycysteine)-forming]; Srx1; sulphiredoxin activity |
| Major function | ATP-dependent reduction of hyperoxidized peroxiredoxins, restoring peroxidase activity |
| Reaction | peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH = peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R |
| Cofactors | ATP and thiol reductants (e.g., glutathione, thioredoxin) |
| Subcellular location | Cytosol, mitochondria, and nucleus (as reported for SRXN1) |
| Representative gene | SRXN1 (sulfiredoxin 1) in humans |
What Is GO:0032542?
According to the Gene Ontology, sulfiredoxin activity (GO:0032542) is defined as the catalysis of the reaction: peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH = peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R. In simpler terms, it is an ATP-hydrolyzing oxidoreductase that uses thiol reducing equivalents to convert an overoxidized cysteine sulfinic acid on a peroxiredoxin back to a cysteine sulfenic acid, thereby reactivating the peroxiredoxin. The activity is also known as peroxiredoxin-(S-hydroxy-S-oxocysteine) reductase activity or sulphiredoxin activity.
Why Is sulfiredoxin activity Important in Cell Biology?
Sulfiredoxin activity is important because it provides a unique mechanism for reversing oxidative inactivation of peroxiredoxins, thereby preserving cellular antioxidant capacity and enabling redox signaling. Without this activity, hyperoxidized peroxiredoxins would remain inactive, leading to accumulation of hydrogen peroxide and oxidative damage. The enzyme is also a stress-responsive gene product, induced by Nrf2 and AP-1, which positions it at the interface of oxidative stress defense and transcriptional programs. In disease contexts, sulfiredoxin has been implicated in cancer cell survival, liver fibrosis, pancreatic redox balance, and circadian regulation, making it a potential therapeutic target [2,3,1,8].
• Maintains peroxiredoxin peroxidase activity by reversing cysteine hyperoxidation.
• Protects cells from oxidative stress-induced damage and apoptosis.
• Regulates hydrogen peroxide signaling by controlling peroxiredoxin inactivation cycles.
• Is transcriptionally induced by Nrf2 and AP-1 in response to oxidative stress.
• Modulates cancer progression, including colorectal cancer suppression via CRL3(Keap1)-mediated degradation of SRX.
• Attenuates hepatic stellate cell activation and liver fibrosis through the PTPN12-NLRP3 axis.
• Influences pancreatic redox signaling in health and disease.
• Exhibits circadian oscillation in mitochondria, linking redox control to metabolic rhythms.
• Interacts with DDAH1 to preserve its activity and regulate intracellular redox homeostasis.
• Serves as a potential biomarker and therapeutic target in oxidative stress-related diseases.
Molecular Mechanism of sulfiredoxin activity
Substrate recognition and binding
In simple terms: Sulfiredoxin finds and binds to an overoxidized peroxiredoxin.
Sulfiredoxin specifically recognizes peroxiredoxins that have been hyperoxidized at their catalytic cysteine to a sulfinic acid (S-hydroxy-S-oxocysteine) form. This modification occurs when peroxiredoxins are exposed to high levels of hydrogen peroxide, leading to overoxidation and inactivation. The binding is thought to involve the conserved active site of sulfiredoxin, which positions the sulfinic acid for reduction.
ATP-dependent activation
In simple terms: ATP provides energy to drive the reduction reaction.
The reduction of the peroxiredoxin sulfinic acid is ATP-dependent; sulfiredoxin hydrolyzes ATP to ADP and phosphate, and this energy is used to form a transient sulfinic phosphoryl ester intermediate. This step is essential for the subsequent thiol-mediated reduction.
Thiol-mediated reduction
In simple terms: Thiol molecules donate electrons to convert the sulfinic acid back to sulfenic acid.
Two thiol equivalents (R-SH), such as glutathione or thioredoxin, are consumed to reduce the sulfinic acid to a sulfenic acid, releasing a disulfide (R-S-S-R). This regenerates the peroxiredoxin's catalytic cysteine to the sulfenic acid state, which can then be reduced further by the peroxiredoxin's own reducing system to restore full peroxidase activity.
Regulation of sulfiredoxin expression
In simple terms: Cells control how much sulfiredoxin is made in response to stress.
Sulfiredoxin expression is induced by oxidative stress through transcription factors Nrf2 and AP-1, which bind to antioxidant response elements in the SRXN1 promoter. This transcriptional regulation ensures that sulfiredoxin levels increase when peroxiredoxins are hyperoxidized, providing a feedback mechanism to restore redox balance. Additionally, sulfiredoxin protein stability can be regulated by ubiquitin-proteasome pathways, as shown for CRL3(Keap1)-mediated degradation of SRX in colorectal cancer.
Interaction with other redox proteins
In simple terms: Sulfiredoxin works with partner proteins to fine-tune redox balance.
Sulfiredoxin interacts with DDAH1, and this interaction recruits peroxiredoxin 1 and sulfiredoxin 1 to preserve DDAH1 activity and regulate intracellular redox homeostasis. This suggests that sulfiredoxin activity is integrated into larger redox protein networks beyond direct peroxiredoxin reduction.
Key Genes Involved in GO:0032542 sulfiredoxin activity
The following genes and proteins are directly involved in sulfiredoxin activity or its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SRXN1 (SRX) | Sulfiredoxin enzyme; catalyzes ATP-dependent reduction of hyperoxidized peroxiredoxins | Core enzyme for GO:0032542; knockout and overexpression models reveal redox regulation |
| PRDX1 | Peroxiredoxin substrate; detoxifies hydrogen peroxide | Hyperoxidation and reduction cycle; interaction with SRXN1 |
| PRDX2 | Peroxiredoxin substrate; antioxidant enzyme | Substrate for sulfiredoxin; involved in redox signaling |
| PRDX3 | Mitochondrial peroxiredoxin substrate | Mitochondrial sulfiredoxin activity and circadian regulation |
| PRDX4 | Peroxiredoxin substrate in ER | Potential substrate; less studied for sulfiredoxin |
| PRDX5 | Peroxiredoxin substrate | May be reduced by sulfiredoxin |
| PRDX6 | Peroxiredoxin with glutathione peroxidase activity | Not a typical sulfiredoxin substrate but part of redox network |
| Nrf2 (NFE2L2) | Transcription factor inducing SRXN1 expression | Regulates antioxidant response; links to sulfiredoxin induction |
| AP-1 | Transcription factor inducing SRXN1 expression | Oxidative stress-responsive regulation of SRXN1 |
| Keap1 (KLHL19) | Substrate adaptor for CRL3 E3 ligase; mediates SRX degradation | Regulates SRX protein stability in cancer |
| DDAH1 | Interacts with SRXN1 and PRDX1 to preserve activity | Redox homeostasis regulation |
| PTPN12 | Phosphatase modulated by sulfiredoxin-1 in liver fibrosis | SRXN1 attenuates HSC activation via PTPN12-NLRP3 axis |
| NLRP3 | Inflammasome component regulated by PTPN12 axis | Inflammation in liver fibrosis |
| TXN | Thioredoxin; provides reducing equivalents for sulfiredoxin reaction | Thiol reductant in vitro and in vivo |
| GSH | Glutathione; thiol reductant | May serve as R-SH in sulfiredoxin reaction |
| SRX1 (yeast) | Yeast sulfiredoxin homolog | Model for studying sulfiredoxin mechanism |
| SRXN1 (mitochondrial) | Mitochondrial isoform of sulfiredoxin | Circadian oscillation in mitochondria |
How Is sulfiredoxin activity Regulated?
Sulfiredoxin activity is regulated at multiple levels. Transcriptionally, SRXN1 is induced by oxidative stress via Nrf2 and AP-1 binding to antioxidant response elements. At the protein level, SRXN1 stability is controlled by ubiquitin-mediated degradation through the CRL3(Keap1) E3 ligase complex, which targets SRX for proteasomal degradation in colorectal cancer. Additionally, sulfiredoxin activity is influenced by the availability of ATP and thiol reductants such as glutathione and thioredoxin, which are required for the catalytic cycle. The enzyme also exhibits circadian oscillation in mitochondria, suggesting temporal regulation. Furthermore, interaction with DDAH1 recruits PRDX1 and SRXN1 to modulate redox homeostasis, indicating a network-level regulation.
sulfiredoxin activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SRXN1 | Colorectal cancer | SRXN1 knockout and overexpression in HCT116 cells; xenograft models |
| SRXN1 | Liver fibrosis | SRXN1 knockout mice; hepatic stellate cell activation assays |
| SRXN1 | Pancreatic oxidative stress | Pancreatic beta cell lines with SRXN1 KO; oxidative stress induction |
| SRXN1 | Circadian mitochondrial metabolism | SRXN1 knockout mice; circadian time-course experiments |
| SRXN1 | General oxidative stress-related diseases | SRXN1 overexpression and knockdown in various cell types |
Sulfiredoxin in cancer
Sulfiredoxin activity contributes to cancer cell survival by maintaining peroxiredoxin function and limiting oxidative damage. In colorectal cancer, the CRL3(Keap1) E3 ligase facilitates ubiquitin-mediated degradation of oncogenic SRX, suggesting that SRX levels are critical for tumor progression. High sulfiredoxin expression has been associated with resistance to oxidative stress-induced cell death, making it a potential therapeutic target.
Sulfiredoxin in liver fibrosis
Sulfiredoxin-1 attenuates hepatic stellate cell activation and liver fibrosis by modulating the PTPN12-NLRP3 axis. This indicates that sulfiredoxin activity can suppress inflammatory and fibrogenic signaling in the liver, and its loss may exacerbate fibrosis.
Sulfiredoxin in pancreatic disease
Redox signaling in the pancreas, including sulfiredoxin activity, is implicated in health and disease. Pancreatic beta cells are sensitive to oxidative stress, and sulfiredoxin may protect against dysfunction by maintaining peroxiredoxin activity.
Sulfiredoxin in circadian and mitochondrial biology
Sulfiredoxin exhibits circadian oscillation in mitochondria, linking redox regulation to metabolic rhythms. This suggests that sulfiredoxin activity may influence mitochondrial function and energy metabolism in a time-of-day-dependent manner.
From sulfiredoxin activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does SRXN1 loss increase oxidative stress sensitivity? | SRXN1 knockout cell lines (e.g., HeLa, HCT116) |
| Does SRXN1 overexpression protect against hyperoxidation? | SRXN1 overexpression stable cell lines |
| What is the role of SRXN1 in liver fibrosis? | SRXN1 knockout mice; hepatic stellate cell activation |
| How does SRXN1 circadian oscillation affect mitochondrial function? | SRXN1 knockout mice; circadian time-course |
| Does SRXN1 interact with DDAH1 to regulate redox? | SRXN1 knockout and DDAH1 knockout cells; co-IP |
| Can SRXN1 point mutations alter catalytic activity? | CRISPR point-mutation knock-in of catalytic cysteine mutants |
How to Study the sulfiredoxin activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Peroxiredoxin hyperoxidation immunoblot | Levels of sulfinylated peroxiredoxin | Assessing sulfiredoxin activity in cells |
| ATP hydrolysis assay | ATP consumption by sulfiredoxin | In vitro enzyme kinetics |
| RNA-seq | SRXN1 and redox gene expression | Transcriptional response to oxidative stress |
| ChIP-seq | Nrf2/AP-1 binding at SRXN1 promoter | Transcriptional regulation |
| Co-immunoprecipitation | Protein-protein interactions (e.g., SRXN1-DDAH1) | Redox protein network |
| CRISPR knockout screening | Genes required for survival under oxidative stress | Synthetic lethality with SRXN1 loss |
| Redox biosensors (HyPer, roGFP) | Real-time H2O2 and GSH/GSSG dynamics | Live-cell redox imaging |
| Circadian time-course qPCR | SRXN1 oscillation in mitochondria | Circadian regulation |
Measuring sulfiredoxin activity
Sulfiredoxin activity can be measured in vitro by monitoring the ATP-dependent reduction of hyperoxidized peroxiredoxins using a coupled enzyme assay or by detecting the disappearance of the sulfinic acid form via immunoblotting with anti-peroxiredoxin-SO2/3 antibodies. These methods allow quantification of enzymatic activity in cell lysates or purified systems.
Transcriptional and proteomic profiling
RNA-seq and proteomics can assess SRXN1 expression and global redox changes upon oxidative stress or genetic manipulation [4,5]. ChIP-seq can identify Nrf2 and AP-1 binding sites in the SRXN1 promoter. Proteomic approaches can identify sulfiredoxin interaction partners such as DDAH1.
Imaging redox dynamics
Genetically encoded redox sensors (e.g., HyPer, roGFP) can monitor hydrogen peroxide and glutathione redox potential in live cells with SRXN1 knockout or overexpression, revealing how sulfiredoxin activity shapes redox dynamics.
CRISPR screening for modifiers
Genome-wide CRISPR knockout or activation screens can identify genes that modulate sensitivity to oxidative stress in SRXN1-deficient cells, uncovering synthetic lethal interactions and pathways that compensate for loss of sulfiredoxin activity.
How CRISPR Can Be Used to Study GO:0032542 sulfiredoxin activity
Knockout
CRISPR knockout of SRXN1 eliminates sulfiredoxin activity, leading to accumulation of hyperoxidized peroxiredoxins and increased sensitivity to oxidative stress. SRXN1 knockout cell lines and mice are valuable for studying the role of sulfiredoxin in cancer, liver fibrosis, and pancreatic disease [2,3,1].
Point Mutation
Point mutations in the catalytic cysteine of SRXN1 (e.g., Cys-to-Ser) can abolish sulfiredoxin activity and are used to dissect the enzymatic mechanism. CRISPR point-mutation knock-in allows precise introduction of such mutations into the endogenous locus, enabling study of catalytic residues in a physiological context.
Knock-in
Knock-in of epitope tags (e.g., FLAG, HA) into the endogenous SRXN1 locus enables affinity purification and proteomic identification of interaction partners such as DDAH1. Knock-in of fluorescent proteins allows live-cell imaging of SRXN1 localization and dynamics.
Overexpression
Overexpression of SRXN1 via CRISPR activation or lentiviral delivery can protect cells from oxidative stress and reduce hyperoxidized peroxiredoxin levels. Overexpression models are useful for testing whether increased sulfiredoxin activity is sufficient to rescue phenotypes in disease models.
How EDITGENE Supports sulfiredoxin activity Research
Researchers studying sulfiredoxin activity-related genes often need to determine whether a candidate gene is causally involved in redox regulation, disease progression, or stress resistance. EDITGENE provides comprehensive CRISPR-based services to create precisely engineered cell models that answer these questions.
Contact EDITGENE today to design your custom CRISPR model for sulfiredoxin activity research.
Frequently Asked Questions About sulfiredoxin activity
What is sulfiredoxin activity?
Sulfiredoxin activity (GO:0032542) is the ATP-dependent reduction of hyperoxidized peroxiredoxins, restoring their peroxidase function.
What genes are involved in sulfiredoxin activity?
The main gene is SRXN1, which encodes sulfiredoxin-1; peroxiredoxins (PRDX1-6) are substrates, and Nrf2/AP-1 regulate SRXN1 expression [4,6].
What is the reaction catalyzed by sulfiredoxin?
It catalyzes: peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH = peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R.
How is sulfiredoxin activity regulated?
It is regulated transcriptionally by Nrf2 and AP-1, and at the protein level by CRL3(Keap1)-mediated degradation [2,4].
What diseases are associated with sulfiredoxin?
Sulfiredoxin is implicated in colorectal cancer, liver fibrosis, pancreatic disease, and circadian mitochondrial metabolism [1,2,3,8].
How can I measure sulfiredoxin activity in the lab?
Common methods include immunoblotting for hyperoxidized peroxiredoxins and ATP hydrolysis assays.
What is the role of sulfiredoxin in cancer?
Sulfiredoxin supports cancer cell survival by maintaining peroxiredoxin activity; its degradation by CRL3(Keap1) suppresses colorectal cancer progression.
Can I use CRISPR to study sulfiredoxin activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect SRXN1 function [2,3,6].
What is the difference between sulfiredoxin and peroxiredoxin?
Peroxiredoxins are antioxidant enzymes that reduce hydrogen peroxide; sulfiredoxin is the enzyme that repairs hyperoxidized peroxiredoxins.
Where is sulfiredoxin located in the cell?
Sulfiredoxin is found in the cytosol, mitochondria, and nucleus, with mitochondrial isoforms showing circadian oscillation.
Conclusion
Sulfiredoxin activity (GO:0032542) is a specialized enzymatic function that reverses peroxiredoxin hyperoxidation, thereby preserving cellular redox homeostasis and enabling hydrogen peroxide signaling. Its regulation by Nrf2, AP-1, and Keap1, as well as its interactions with DDAH1 and circadian machinery, highlight its integration into stress-responsive and metabolic networks [2,4,5,8]. Dysregulation of sulfiredoxin is linked to cancer, liver fibrosis, pancreatic disease, and oxidative stress-related pathologies, making it a compelling target for further research [1,2,3,7]. CRISPR-based models from EDITGENE can accelerate the functional dissection of SRXN1 and its partners in these disease contexts.
References
- 1. Sastre J et al.. 2025. Redox signaling in the pancreas in health and disease.. Physiol Rev 105(2):593-650 PMID: 39324871
- 2. Zhu F et al.. 2024. CRL3(Keap1) E3 ligase facilitates ubiquitin-mediated degradation of oncogenic SRX to suppress colorectal cancer progression.. Nat Commun 15(1):10536 PMID: 39627198
- 3. Kim JW et al.. 2025. The desulfinylation enzyme sulfiredoxin-1 attenuates HSC activation and liver fibrosis by modulating the PTPN12-NLRP3 axis.. Hepatology 82(1):92-109 PMID: 39446334
- 4. Soriano FX et al.. 2009. Transcriptional regulation of the AP-1 and Nrf2 target gene sulfiredoxin.. Mol Cells 27(3):279-82 PMID: 19326073
- 5. Yuan J et al.. 2024. DDAH1 recruits peroxiredoxin 1 and sulfiredoxin 1 to preserve its activity and regulate intracellular redox homeostasis.. Redox Biol 70:103080 PMID: 38354630
- 6. Jeong W et al.. 2012. Role of sulfiredoxin as a regulator of peroxiredoxin function and regulation of its expression.. Free Radic Biol Med 53(3):447-56 PMID: 22634055
- 7. Ramesh A et al.. 2014. Role of sulfiredoxin in systemic diseases influenced by oxidative stress.. Redox Biol 2:1023-8 PMID: 25460739
- 8. Kil IS et al.. 2015. Circadian Oscillation of Sulfiredoxin in the Mitochondria.. Mol Cell 59(4):651-63 PMID: 26236015
