GO:0050337 thiosulfate-thiol sulfurtransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0050337 thiosulfate-thiol sulfurtransferase activity catalyzes the reaction thiosulfate + 2 glutathione = glutathione disulfide + hydrogen sulfide + sulfite + 2 H+, as defined by QuickGO.
• The enzyme is a glutathione-dependent sulfurtransferase that produces hydrogen sulfide (H2S), a gasotransmitter involved in mitochondrial function and redox signaling.
• In mammals, the principal enzyme carrying this activity is 3-mercaptopyruvate sulfurtransferase (MPST), which also catalyzes thiosulfate-thiol sulfurtransferase reactions.
• MPST deficiency is linked to intestinal epithelial apoptosis and inflammatory bowel disease via AKT signaling, and MPST protects against metabolic syndrome and vascular inflammation.
• Small molecules that activate thiosulfate sulfurtransferase stimulate mitochondrial respiration, highlighting the pathway as a druggable target.
• Research on this activity employs knockout, point-mutation, knock-in, and overexpression cell models, along with CRISPR library screening and bioinformatics to dissect gene function.
Description
Thiosulfate-thiol sulfurtransferase activity (GO:0050337) is a molecular function that catalyzes the transfer of sulfur from thiosulfate to a thiol, typically glutathione, yielding glutathione disulfide, hydrogen sulfide, sulfite, and protons. This activity is central to sulfur metabolism and H2S production, a gasotransmitter with roles in mitochondrial bioenergetics, redox homeostasis, and cellular signaling. Researchers study this term to understand how cells detoxify sulfur compounds, generate H2S, and regulate oxidative stress responses. The enzyme MPST is the best-characterized mammalian protein with this activity, and its dysfunction has been implicated in inflammatory bowel disease, metabolic syndrome, and cardiotoxicity. Understanding GO:0050337 provides a mechanistic basis for targeting sulfurtransferase pathways in disease.
thiosulfate-thiol sulfurtransferase activity At A Glance
| GO ID | GO:0050337 |
|---|---|
| GO term | thiosulfate-thiol sulfurtransferase activity |
| Ontology | molecular_function |
| Synonym | glutathione-dependent thiosulfate reductase activity; sulfane reductase activity; sulfane sulfurtransferase activity; thiosulfate:thiol sulfurtransferase activity; thiosulphate-thiol sulphurtransferase activity |
| Major function | Catalyzes the transfer of sulfur from thiosulfate to a thiol, producing hydrogen sulfide, sulfite, and glutathione disulfide |
| Reaction | thiosulfate + 2 glutathione = glutathione disulfide + hydrogen sulfide + sulfite + 2 H+ |
| Substrates | Thiosulfate, glutathione (or other thiols) |
| Products | Glutathione disulfide, hydrogen sulfide, sulfite, protons |
| Cofactors | None required; uses thiol as sulfur acceptor |
| Related genes | MPST, TST, and other sulfurtransferases |
What Is GO:0050337?
According to QuickGO, GO:0050337 thiosulfate-thiol sulfurtransferase activity is defined as the catalysis of the reaction: thiosulfate + 2 glutathione = glutathione disulfide + hydrogen sulfide + sulfite + 2 H+. In other words, it is a sulfurtransferase that uses thiosulfate as a sulfur donor and a thiol (such as glutathione) as an acceptor, releasing H2S and sulfite as products. This activity is synonymous with glutathione-dependent thiosulfate reductase, sulfane reductase, and sulfane sulfurtransferase activities.
Why Is thiosulfate-thiol sulfurtransferase activity Important in Cell Biology?
Thiosulfate-thiol sulfurtransferase activity is important because it generates hydrogen sulfide (H2S), a signaling molecule that regulates mitochondrial function, vascular tone, and inflammation. Dysregulation of this activity has been linked to inflammatory bowel disease, metabolic syndrome, and doxorubicin-induced cardiotoxicity. Moreover, small-molecule activators of thiosulfate sulfurtransferase stimulate mitochondrial respiration, suggesting therapeutic potential. Thus, understanding GO:0050337 is critical for developing treatments for diseases involving sulfur metabolism and oxidative stress.
• Produces hydrogen sulfide (H2S), a gasotransmitter involved in mitochondrial bioenergetics and redox signaling.
• MPST, a key enzyme with this activity, protects against intestinal epithelial apoptosis and inflammatory bowel disease.
• MPST deficiency exacerbates metabolic syndrome and vascular inflammation.
• The activity is implicated in doxorubicin-induced cardiotoxicity via oxidative stress and mitochondrial dysfunction.
• Small-molecule activation of thiosulfate sulfurtransferase enhances mitochondrial respiration.
• Serves as a target for modulating sulfur metabolism in cancer and inflammatory diseases.
• Enables detoxification of thiosulfate and maintenance of cellular thiol redox balance.
• Provides a mechanism for H2S-based signaling independent of cystathionine beta-synthase and cystathionine gamma-lyase.
• Relevant to bacterial pathogenesis, as Mycobacterium tuberculosis CysA2 exhibits dual sulfurtransferase activity.
• Offers a druggable pathway for metabolic and cardiovascular disorders.
Molecular Mechanism of thiosulfate-thiol sulfurtransferase activity
Substrate Binding and Sulfur Transfer
In simple terms: The enzyme grabs sulfur from thiosulfate and hands it to glutathione, releasing H2S.
The catalytic mechanism begins with the binding of thiosulfate and a thiol substrate, typically glutathione, to the active site of the enzyme. The enzyme facilitates the nucleophilic attack of the thiol on the sulfur atom of thiosulfate, leading to the formation of a persulfide intermediate and the release of sulfite. This step is essential for sulfur transfer and is characteristic of thiosulfate-thiol sulfurtransferases.
Hydrogen Sulfide Release
In simple terms: The enzyme then releases hydrogen sulfide, a gas that signals within cells.
Following sulfur transfer, the persulfide intermediate is reduced by a second glutathione molecule, releasing hydrogen sulfide (H2S) and glutathione disulfide. This H2S can act as a signaling molecule, modulating mitochondrial function and redox balance. The reaction also produces protons, contributing to cellular pH regulation.
Enzyme Structure and Active Site
In simple terms: The enzyme has a special pocket that holds the substrates and a critical cysteine that carries sulfur.
Thiosulfate-thiol sulfurtransferases, such as MPST, possess a catalytic cysteine residue that forms a persulfide intermediate during catalysis. The active site architecture ensures specificity for thiosulfate and thiols, and structural studies have revealed key residues involved in substrate binding. MPST is a monomeric enzyme with two domains, and its activity is regulated by redox state.
Cofactors and Regulation
In simple terms: The enzyme does not need special cofactors but depends on glutathione availability and redox conditions.
The activity requires no exogenous cofactors; however, it is dependent on the availability of reduced glutathione as a sulfur acceptor. The enzyme's activity can be modulated by oxidative stress, as the catalytic cysteine is sensitive to oxidation. Additionally, small molecules can activate thiosulfate sulfurtransferase, enhancing mitochondrial respiration.
Key Genes Involved in GO:0050337 thiosulfate-thiol sulfurtransferase activity
The following genes and proteins are directly associated with thiosulfate-thiol sulfurtransferase activity or its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MPST | Primary enzyme with thiosulfate-thiol sulfurtransferase activity; produces H2S | Knockout models show intestinal apoptosis and metabolic syndrome; target for activators |
| TST | Thiosulfate sulfurtransferase (rhodanese) with related activity | Small molecule activators stimulate mitochondrial respiration |
| CysA2 | Mycobacterial dual sulfurtransferase active on thiosulfate | Interacts with mammalian cells; potential drug target |
| GSS | Glutathione synthetase; maintains glutathione pool | Provides substrate for the reaction |
| GSR | Glutathione reductase; regenerates reduced glutathione | Supports sustained activity |
| CBS | Cystathionine beta-synthase; alternative H2S source | Cross-talk with MPST pathways |
| CTH | Cystathionine gamma-lyase; alternative H2S source | Cross-talk with MPST pathways |
| AKT1 | Signaling kinase; modulated by MPST deficiency | Mediates apoptosis in IBD |
| Nrf2 | Transcription factor regulating antioxidant response | May regulate MPST expression |
| RNF2 | E3 ubiquitin ligase; promotes oxidative stress via MPST/H2S pathway | Cardiotoxicity model |
| Urm1 | Ubiquitin-like protein; sulfurtransferase in tRNA thiolation | Model for sulfur transfer mechanisms |
| SQOR | Sulfide:quinone oxidoreductase; consumes H2S | Regulates H2S levels |
| ETHE1 | Persulfide dioxygenase; sulfur metabolism | Related to H2S catabolism |
| SULT1A1 | Sulfotransferase; not directly related but sulfur metabolism | Context for sulfur transfer |
| MPST-KO | Knockout models for MPST | Used to study loss of activity |
| MPST-OE | Overexpression models | Used to study gain of function |
| TST-KO | Knockout models for TST | Used to study mitochondrial respiration |
How Is thiosulfate-thiol sulfurtransferase activity Regulated?
Thiosulfate-thiol sulfurtransferase activity is regulated at multiple levels. The catalytic cysteine of MPST is redox-sensitive, and oxidative stress can inhibit its activity. Glutathione availability directly influences the reaction rate, as it is a co-substrate. Additionally, small molecules can allosterically activate thiosulfate sulfurtransferase, enhancing mitochondrial respiration. In inflammatory conditions, MPST expression is modulated by AKT signaling, affecting cell survival. The pathway also intersects with H2S signaling, which can feedback to regulate enzyme activity.
thiosulfate-thiol sulfurtransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MPST | Inflammatory bowel disease | MPST knockout intestinal epithelial cells |
| MPST | Metabolic syndrome and vascular inflammation | MPST knockout mouse models |
| MPST | Doxorubicin-induced cardiotoxicity | Cardiomyocyte-specific MPST knockout |
| MPST | Mitochondrial function and exercise performance | MPST overexpression in muscle cells |
| TST | Mitochondrial respiration | TST knockout cells treated with activators |
Inflammatory Bowel Disease
MPST deficiency promotes intestinal epithelial cell apoptosis and aggravates inflammatory bowel disease via AKT signaling. Loss of thiosulfate-thiol sulfurtransferase activity leads to reduced H2S production, impairing cytoprotection and increasing susceptibility to inflammation. This suggests that enhancing MPST activity could be therapeutic in IBD.
Metabolic Syndrome and Vascular Inflammation
MPST plays a protective role in the development of metabolic syndrome and vascular inflammation. Reduced thiosulfate-thiol sulfurtransferase activity is associated with endothelial dysfunction and increased oxidative stress. Targeting this pathway may improve metabolic and vascular health.
Doxorubicin-Induced Cardiotoxicity
Ring finger protein 2 promotes oxidative stress and mitochondrial dysfunction in doxorubicin-induced cardiotoxicity via the MPST/H2S pathway. Dysregulation of thiosulfate-thiol sulfurtransferase activity contributes to cardiac injury, and modulating this pathway may be cardioprotective.
Mitochondrial Function and Exercise Performance
Ergothioneine controls mitochondrial function and exercise performance via direct activation of MPST. This highlights the role of thiosulfate-thiol sulfurtransferase activity in energy metabolism and physical performance.
From thiosulfate-thiol sulfurtransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of MPST loss on intestinal apoptosis? | MPST knockout (KO) cell lines and mouse models |
| Does a point mutation in the catalytic cysteine abolish activity? | Point-mutation knock-in of MPST C247S |
| Can overexpression of MPST protect against oxidative stress? | MPST overexpression cell lines |
| How does tagged MPST localize in cells? | Tagged knock-in of MPST with GFP |
| What genes are synthetic lethal with MPST loss? | CRISPR library screening in MPST-KO background |
| Does activation of TST improve mitochondrial respiration? | TST overexpression and small molecule treatment |
How to Study the thiosulfate-thiol sulfurtransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Colorimetric sulfurtransferase assay | Enzyme activity via sulfite/H2S production | Validation of MPST/TST activity |
| CRISPR knockout | Loss of gene function | Studying MPST in IBD and metabolism |
| Point mutation knock-in | Effect of specific amino acid changes | Catalytic mechanism |
| Overexpression | Gain of function | Protection against oxidative stress |
| H2S fluorescent probe | Intracellular H2S levels | Live-cell imaging |
| RNA-seq | Transcriptional changes | Pathway analysis upon MPST modulation |
| Proteomics | Protein expression and modifications | Identifying interacting partners |
| CRISPR library screening | Genome-wide fitness | Synthetic lethal interactions |
Enzymatic Activity Assays
Thiosulfate-thiol sulfurtransferase activity can be measured spectrophotometrically by monitoring the production of sulfite or H2S using colorimetric reagents. These assays are used to validate enzyme function in cell lysates or purified protein.
Genetic Knockout and Knock-in Models
CRISPR-Cas9 mediated knockout of MPST or TST allows researchers to assess loss of function in cellular and animal models. Knock-in of point mutations, such as catalytic cysteine to serine, helps dissect the mechanism.
H2S Detection and Imaging
Hydrogen sulfide production can be visualized using fluorescent probes or measured with electrochemical sensors. These methods link enzyme activity to cellular signaling.
Transcriptomics and Proteomics
RNA-seq and proteomics can reveal changes in gene expression and protein abundance upon modulation of thiosulfate-thiol sulfurtransferase activity. Bioinformatics analysis identifies pathways affected.
How CRISPR Can Be Used to Study GO:0050337 thiosulfate-thiol sulfurtransferase activity
Knockout
CRISPR knockout of MPST or TST is used to study the loss of thiosulfate-thiol sulfurtransferase activity. MPST knockout cells exhibit increased apoptosis and impaired mitochondrial function. These models help establish causality between enzyme activity and disease phenotypes.
Point Mutation
Point mutations in the catalytic cysteine of MPST (e.g., C247S) can be introduced via CRISPR to abolish sulfurtransferase activity without affecting protein stability. Such models are valuable for distinguishing catalytic activity from structural roles.
Knock-in
Knock-in of tagged MPST (e.g., GFP or HA) allows for localization and interaction studies. This approach preserves endogenous regulation while enabling visualization.
Overexpression
Overexpression of MPST or TST via CRISPR activation or lentiviral delivery can enhance thiosulfate-thiol sulfurtransferase activity. Overexpression models are used to test protective effects against oxidative stress and mitochondrial dysfunction.
How EDITGENE Supports thiosulfate-thiol sulfurtransferase activity Research
Researchers studying thiosulfate-thiol sulfurtransferase activity-related genes often need to determine whether a candidate gene is causally involved in sulfur metabolism, H2S production, or disease phenotypes. EDITGENE provides comprehensive CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for thiosulfate-thiol sulfurtransferase activity research.
Frequently Asked Questions About thiosulfate-thiol sulfurtransferase activity
What is thiosulfate-thiol sulfurtransferase activity?
It is a molecular function (GO:0050337) that catalyzes the reaction thiosulfate + 2 glutathione = glutathione disulfide + hydrogen sulfide + sulfite + 2 H+, as defined by QuickGO.
What genes are involved in thiosulfate-thiol sulfurtransferase activity?
The main gene is MPST, which encodes 3-mercaptopyruvate sulfurtransferase; TST also exhibits related activity.
What is the role of MPST in disease?
MPST deficiency is linked to inflammatory bowel disease, metabolic syndrome, and cardiotoxicity.
How is thiosulfate-thiol sulfurtransferase activity measured?
It can be measured using colorimetric assays that detect sulfite or hydrogen sulfide production.
What is the reaction catalyzed by GO:0050337?
The reaction is thiosulfate + 2 glutathione = glutathione disulfide + hydrogen sulfide + sulfite + 2 H+.
What are synonyms for thiosulfate-thiol sulfurtransferase activity?
Synonyms include glutathione-dependent thiosulfate reductase, sulfane reductase, and sulfane sulfurtransferase.
Which diseases are associated with MPST dysfunction?
Inflammatory bowel disease, metabolic syndrome, vascular inflammation, and doxorubicin-induced cardiotoxicity.
Can thiosulfate-thiol sulfurtransferase activity be targeted by drugs?
Yes, small molecules that activate thiosulfate sulfurtransferase stimulate mitochondrial respiration.
What model systems are used to study this activity?
Knockout, point-mutation, knock-in, and overexpression cell models, as well as animal models.
How does hydrogen sulfide relate to this activity?
Hydrogen sulfide is a product of the reaction and acts as a signaling molecule in mitochondrial function and redox balance.
Conclusion
Thiosulfate-thiol sulfurtransferase activity (GO:0050337) is a key enzymatic function in sulfur metabolism and H2S production, with critical roles in mitochondrial function, inflammation, and cardiovascular health. Understanding its mechanism and regulation offers therapeutic opportunities for metabolic and inflammatory diseases. EDITGENE provides advanced CRISPR tools to study this pathway and accelerate drug discovery.
References
- 1. Sprenger HG et al.. 2025. Ergothioneine controls mitochondrial function and exercise performance via direct activation of MPST.. Cell Metab 37(4):857-869.e9 PMID: 39965563
- 2. Kimura H. 2017. Hydrogen Sulfide and Polysulfide Signaling.. Antioxid Redox Signal 27(10):619-621 PMID: 28558483
- 3. Zhang J et al.. 2022. MPST deficiency promotes intestinal epithelial cell apoptosis and aggravates inflammatory bowel disease via AKT.. Redox Biol 56:102469 PMID: 36126419
- 4. Termathe M et al.. 2021. Urm1: A Non-Canonical UBL.. Biomolecules 11(2) PMID: 33499055
- 5. Meza AN et al.. 2019. Mycobacterium tuberculosis CysA2 is a dual sulfurtransferase with activity against thiosulfate and 3-mercaptopyruvate and interacts with mammalian cells.. Sci Rep 9(1):16791 PMID: 31727914
- 6. Zampas P et al.. 2025. Protective role of 3-mercaptopyruvate sulfurtransferase (MPST) in the development of metabolic syndrome and vascular inflammation.. Pharmacol Res 211:107542 PMID: 39667544
- 7. Zhong Y et al.. 2025. Ring Finger Protein 2 Promotes Oxidative Stress and Mitochondrial Dysfunction in Doxorubicin-Induced Cardiotoxicity Via the Mercaptopyruvate Sulfurtransferase/Hydrogen Sulfide Pathway.. J Am Heart Assoc 14(16):e041440 PMID: 40767300
- 8. Al-Dahmani ZM et al.. 2023. Identification and characterization of a small molecule that activates thiosulfate sulfurtransferase and stimulates mitochondrial respiration.. Protein Sci 32(11):e4794 PMID: 37800277
