GO:0004081 bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004081 describes the asymmetrical hydrolysis of P(1),P(4)-bis(5'-nucleosyl)tetraphosphates such as diadenosine tetraphosphate (Ap4A) into an NTP and an NMP.
• The reaction is catalyzed by dinucleoside tetraphosphatases (Ap4A hydrolases) that cleave asymmetrically, producing ATP plus AMP from Ap4A.
• These enzymes are found across eukaryotes, plants and bacteria, and include the bacterial ApaH protein that supports virulence in Pseudomonas aeruginosa.
• Human dinucleoside tetraphosphatase activity has been purified from blood cells and placenta, confirming its presence in clinically relevant tissues.
• The enzyme acts on bis(5'-guanosyl)-, bis(5'-xanthosyl)-, bis(5'-adenosyl)- and bis(5'-uridyl)-tetraphosphates, indicating broad dinucleoside tetraphosphate specificity.
• Studying GO:0004081 helps researchers understand dinucleotide second-messenger signaling, nucleotide homeostasis and bacterial pathogenesis.
Description
GO:0004081, bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity, is a molecular function that catalyzes the hydrolysis of P(1),P(4)-bis(5'-nucleosyl)tetraphosphate to yield an NTP and an NMP. This asymmetrical cleavage is distinct from symmetrical hydrolysis because the two phosphoanhydride bonds are not equivalent, and the enzyme preferentially attacks one side of the tetraphosphate bridge. The reaction is best known for diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A), a dinucleotide that has been studied as a signaling molecule and a marker of cellular stress. Researchers care about this activity because dinucleoside tetraphosphates participate in nucleotide metabolism, DNA repair signaling and stress responses, and their hydrolysis controls the lifetime of these molecules. The enzyme has been characterized in rat tissues, human blood cells, human placenta, higher plants and bacteria, showing that GO:0004081 is evolutionarily conserved and biologically important.
bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity At A Glance
| GO ID | GO:0004081 |
|---|---|
| GO term | bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity |
| Ontology | molecular_function |
| Synonym | Ap4A hydrolase activity; diadenosine 5',5'''-P1,P4-tetraphosphate asymmetrical hydrolase activity; dinucleoside tetraphosphatase activity |
| Major function | Asymmetrical hydrolysis of dinucleoside tetraphosphates to NTP and NMP |
| Substrates | Bis(5'-guanosyl)-, bis(5'-xanthosyl)-, bis(5'-adenosyl)- and bis(5'-uridyl)-tetraphosphates |
| Representative enzymes | Rat liver dinucleoside tetraphosphatase, human blood cell and placental Ap4A hydrolase, plant diadenosine tetraphosphatase, bacterial ApaH |
| Reaction products | NTP and NMP, for example ATP and AMP from Ap4A |
What Is GO:0004081?
In simple terms, GO:0004081 is the activity of an enzyme that cuts a dinucleoside tetraphosphate asymmetrically, releasing one nucleotide triphosphate and one nucleotide monophosphate. The official definition states: Catalysis of the reaction P(1),P(4)-bis(5'-nucleosyl)tetraphosphate + H2O = NTP + NMP, acting on bis(5'-guanosyl)-, bis(5'-xanthosyl)-, bis(5'-adenosyl)- and bis(5'-uridyl)-tetraphosphate. This means the enzyme recognizes a tetraphosphate bridge linking two nucleosides and hydrolyzes one specific phosphoanhydride bond, rather than cleaving both sides symmetrically.
Why Is bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity Important in Cell Biology?
GO:0004081 matters because it controls the cellular levels of dinucleoside tetraphosphates such as Ap4A, which have been linked to nucleotide homeostasis, stress signaling and bacterial virulence. The asymmetrical hydrolase activity determines whether Ap4A is converted to ATP plus AMP or handled by other enzymes, and this balance influences downstream nucleotide pools. Because the enzyme has been purified from human blood cells and placenta, it is also relevant to human physiology and disease research.
• Controls the catabolism of Ap4A, a dinucleotide implicated in cellular stress responses.
• Provides a route to regenerate ATP and AMP from dinucleoside tetraphosphates.
• Is conserved from plants to humans, making it a tractable comparative biology target.
• Bacterial ApaH, a related diadenosine tetraphosphatase, is important for Pseudomonas aeruginosa virulence.
• Human blood cell and placental enzymes have been purified, supporting clinical relevance.
• The activity can be assayed with NTP and Np4N substrates, enabling mechanistic studies.
• Dinucleoside tetraphosphatase can be distinguished from phosphodiesterase I-like enzymes in rat liver.
• Affinity elution with adenosine 5'-tetraphosphate has enabled purification of the rat liver enzyme.
• The enzyme acts on multiple dinucleoside tetraphosphate substrates, suggesting broad nucleotide surveillance.
• Understanding GO:0004081 supports drug discovery against bacterial pathogens that rely on ApaH.
Molecular Mechanism of bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity
Substrate recognition of dinucleoside tetraphosphates
In simple terms: The enzyme first grabs a molecule that has two nucleosides joined by four phosphates.
The asymmetrical tetraphosphatase recognizes P(1),P(4)-bis(5'-nucleosyl)tetraphosphates, including bis(5'-guanosyl)-, bis(5'-xanthosyl)-, bis(5'-adenosyl)- and bis(5'-uridyl)-tetraphosphate. Rat tissue studies showed that bis(5'-guanosyl) tetraphosphate is a substrate, indicating that the enzyme is not limited to Ap4A. The enzyme can be purified using affinity elution with adenosine 5'-tetraphosphate, which reflects its affinity for the tetraphosphate moiety.
Asymmetrical cleavage of the tetraphosphate bridge
In simple terms: Instead of cutting the bridge in the middle, the enzyme cuts one specific side, leaving an NTP and an NMP.
The defining feature of GO:0004081 is asymmetrical hydrolysis: P(1),P(4)-bis(5'-nucleosyl)tetraphosphate + H2O = NTP + NMP. This differs from symmetrical cleavage, which would yield two dinucleoside diphosphates. Rat liver contains two low-Km hydrolytic activities on dinucleoside 5',5'''-P1,P4-tetraphosphates, one of which is the specific dinucleoside tetraphosphatase and the other a phosphodiesterase I-like enzyme. The specific enzyme produces ATP and AMP from Ap4A, confirming asymmetrical attack.
Catalytic properties and substrate specificity
In simple terms: The enzyme prefers certain dinucleoside tetraphosphates and works efficiently at low substrate concentrations.
Human placental asymmetrical diadenosine 5',5'''-P1,P4-tetraphosphate hydrolase was purified to homogeneity and characterized, confirming its catalytic identity. Human blood cell dinucleoside tetraphosphatase was purified and shown to be a high specific activity enzyme recognized by an anti-rat tetraphosphatase antibody, indicating conserved structural features. Firefly luciferase studies showed that 2',3'-dideoxynucleoside triphosphates and di-2',3'-dideoxynucleoside tetraphosphates behave differently from their NTP and Np4N counterparts as substrates of dinucleoside tetraphosphatase, revealing substrate discrimination.
Enzyme sources and comparative biochemistry
In simple terms: Similar enzymes are found in animals, plants and bacteria, which helps researchers compare their behavior.
Bis-(5'-guanosyl) tetraphosphatase activity was detected in rat tissues, establishing a mammalian source for the activity. In higher plants, diadenosine tetraphosphatase was purified from yellow lupin seeds along with diadenosine triphosphatase and phosphodiesterase, showing that plants also carry this activity. In bacteria, structural and functional studies of Pseudomonas aeruginosa ApaH, a diadenosine tetraphosphatase, revealed that it is crucial for bacterial virulence.
Regulation and cellular context
In simple terms: The enzyme's job is to keep dinucleoside tetraphosphate levels under control in different cell types.
The presence of the enzyme in human blood cells and placenta suggests that GO:0004081 operates in diverse physiological settings. Rat liver contains both a specific dinucleoside tetraphosphatase and a phosphodiesterase I-like activity, indicating that multiple enzymes can act on dinucleoside tetraphosphates and that their relative contributions may be regulated. The bacterial ApaH enzyme is important for virulence, implying that its activity is integrated into infection-related programs.
Key Genes Involved in GO:0004081 bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity
The genes and proteins below are experimentally linked to bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity or to the dinucleoside tetraphosphate substrates it acts on.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ApaH (Pseudomonas aeruginosa) | Diadenosine tetraphosphatase required for virulence | Bacterial pathogenesis and antimicrobial target studies |
| Rat liver dinucleoside tetraphosphatase | Specific asymmetrical hydrolase of Ap4A | Enzyme purification and kinetic characterization |
| Human blood cell dinucleoside tetraphosphatase | High specific activity Ap4A hydrolase | Human enzyme characterization and antibody cross-reactivity |
| Human placental Ap4A hydrolase | Asymmetrical diadenosine tetraphosphate hydrolase | Purification to homogeneity and property analysis |
| Yellow lupin diadenosine tetraphosphatase | Plant dinucleoside tetraphosphate hydrolase | Comparative plant enzyme biochemistry |
| Rat tissue bis(5'-guanosyl) tetraphosphatase | Hydrolysis of bis(5'-guanosyl) tetraphosphate | Substrate specificity and tissue distribution |
| Firefly luciferase (substrate comparison) | Model enzyme for NTP and Np4N substrate studies | Substrate discrimination experiments |
| Phosphodiesterase I-like enzyme (rat liver) | Alternative dinucleoside tetraphosphate hydrolase | Distinguishing specific versus nonspecific activities |
| Diadenosine triphosphatase (plant) | Hydrolyzes ApppA | Related dinucleotide catabolism |
| Plant phosphodiesterase | Broad nucleotide phosphodiesterase | Comparative enzyme purification |
| Ap4A (diadenosine tetraphosphate) | Substrate and signaling dinucleotide | Stress response and nucleotide homeostasis |
| Ap5A and related dinucleoside polyphosphates | Related substrates studied with luciferase | Substrate specificity of dinucleoside tetraphosphatase |
| ddNTP and ddNp4ddN analogs | Modified substrates for enzyme assays | Mechanistic discrimination studies |
| Adenosine 5'-tetraphosphate | Affinity ligand for enzyme purification | Purification of rat liver dinucleoside tetraphosphatase |
| Anti-rat tetraphosphatase antibody | Immunological detection of human enzyme | Cross-species conservation studies |
How Is bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity Regulated?
The activity of bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) is regulated at the level of substrate availability and enzyme expression. Rat liver contains two low-Km hydrolytic activities on dinucleoside tetraphosphates, one specific dinucleoside tetraphosphatase and one phosphodiesterase I-like enzyme, suggesting that the balance between these enzymes influences net hydrolysis. Human blood cell and placental enzymes have been purified as distinct proteins, indicating tissue-specific expression. In bacteria, ApaH is crucial for virulence, implying that its activity is integrated into infection-related regulatory networks. The enzyme can be purified by affinity elution with adenosine 5'-tetraphosphate, which also suggests that tetraphosphate-containing ligands can modulate its behavior.
bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ApaH (Pseudomonas aeruginosa) | Bacterial virulence | ApaH knockout in P. aeruginosa infection models |
| Human blood cell dinucleoside tetraphosphatase | Hematological nucleotide metabolism | Knockout or knockdown in human blood cell lines |
| Human placental Ap4A hydrolase | Placental biology and nucleotide homeostasis | Placental cell models with overexpression or knockout |
| Rat liver dinucleoside tetraphosphatase | Hepatic nucleotide catabolism | Rat liver cell lines and enzyme assays |
| Plant diadenosine tetraphosphatase | Plant stress and nucleotide metabolism | Plant knockout lines and biochemical assays |
Bacterial virulence and infection
Pseudomonas aeruginosa ApaH, a diadenosine tetraphosphatase, is crucial for bacterial virulence, making GO:0004081 a potential target for anti-virulence strategies. Structural and functional insights into ApaH provide a basis for designing inhibitors that could disarm pathogens without directly killing them.
Nucleotide metabolism and stress signaling
Ap4A and related dinucleoside tetraphosphates are linked to cellular stress and nucleotide homeostasis, and their asymmetrical hydrolysis by GO:0004081 controls their lifetime. Dysregulation of this activity could alter ATP and AMP pools, which are central to energy metabolism and signaling.
Human tissue enzyme expression
The purification of dinucleoside tetraphosphatase from human blood cells and placenta demonstrates that the enzyme is present in clinically accessible human tissues. This supports further investigation of its role in hematological and placental biology.
From bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ApaH reduce bacterial virulence? | ApaH knockout in Pseudomonas aeruginosa |
| What is the kinetic impact of a point mutation in the catalytic site? | Point-mutation knock-in in human or bacterial enzyme expression systems |
| Can a tagged enzyme be used to track localization? | Tagged knock-in of dinucleoside tetraphosphatase |
| Does overexpression alter Ap4A levels? | Overexpression of human or rat dinucleoside tetraphosphatase |
| Which substrates are preferred by the enzyme? | In vitro assays with purified enzyme and Np4N substrates |
| Is the enzyme conserved across species? | Comparative knockout or knockdown in plant and mammalian cells |
How to Study the bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme activity assay with Ap4A | Hydrolysis of dinucleoside tetraphosphate | Kinetic characterization of purified enzyme |
| Firefly luciferase assay | Substrate discrimination between NTP and Np4N | Comparing natural and modified substrates |
| Affinity elution chromatography | Enzyme purification | Obtaining homogeneous rat liver enzyme |
| Immunoblotting with anti-tetraphosphatase antibody | Protein detection and cross-species reactivity | Comparing human and rat enzymes |
| Structural biology (crystallography or modeling) | Three-dimensional structure of ApaH | Understanding catalytic mechanism and virulence |
| Plant enzyme purification | Diadenosine tetraphosphatase activity in plants | Comparative biochemistry in lupin seeds |
| Tissue distribution studies | Enzyme presence across rat tissues | Identifying major sites of activity |
| Substrate specificity profiling | Activity on guanosyl, xanthosyl, adenosyl and uridyl substrates | Defining the range of GO:0004081 |
Enzyme activity assays
Dinucleoside tetraphosphatase activity can be measured by incubating purified enzyme with Ap4A or other Np4N substrates and detecting the NTP and NMP products. Firefly luciferase-based assays have been used to compare NTP and Np4N substrates and to study ddNTP and ddNp4ddN behavior.
Protein purification and affinity chromatography
The rat liver enzyme has been purified to homogeneity by affinity elution with adenosine 5'-tetraphosphate, providing a method to obtain pure protein for kinetic studies. Human placental and blood cell enzymes have also been purified to homogeneity or high specific activity, enabling detailed characterization.
Immunological detection
An anti-rat tetraphosphatase antibody recognized the human blood cell enzyme, showing that immunological methods can detect and compare the enzyme across species. Such antibodies are useful for western blotting and immunoprecipitation.
Structural and functional studies
Structural and functional insights into Pseudomonas aeruginosa ApaH have been obtained, providing a framework for understanding the catalytic mechanism of GO:0004081. These studies can guide mutagenesis and inhibitor design.
How CRISPR Can Be Used to Study GO:0004081 bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity
Knockout
CRISPR knockout of genes encoding dinucleoside tetraphosphatases can eliminate GO:0004081 activity in cells, allowing researchers to test whether Ap4A accumulates and whether downstream phenotypes depend on the enzyme. In bacteria, ApaH knockout can be used to assess virulence loss.
Point Mutation
Point mutations in catalytic residues can be introduced to dissect the asymmetrical cleavage mechanism and to separate substrate binding from catalysis. Such mutants help confirm which residues are essential for hydrolysis of dinucleoside tetraphosphates.
Knock-in
Knock-in of tagged versions of the enzyme can be used to track its localization and interactions in cells. Tagged knock-in also enables affinity purification of the enzyme from native tissues.
Overexpression
Overexpression of human or rat dinucleoside tetraphosphatase can lower cellular Ap4A levels and reveal the consequences of enhanced hydrolysis. Overexpression models are useful for testing whether the enzyme is rate-limiting for dinucleoside tetraphosphate turnover.
How EDITGENE Supports bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity Research
Researchers studying bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity-related genes often need to determine whether a candidate gene is causally involved in dinucleoside tetraphosphate metabolism, stress signaling or bacterial virulence. EDITGENE provides CRISPR-based cell models and screening services to test these hypotheses directly.
Contact EDITGENE today to design your custom CRISPR model for bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity research.
Frequently Asked Questions About bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity
What is bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity?
It is a molecular function, GO:0004081, that catalyzes the asymmetrical hydrolysis of P(1),P(4)-bis(5'-nucleosyl)tetraphosphate to an NTP and an NMP.
What reaction does GO:0004081 catalyze?
The reaction is P(1),P(4)-bis(5'-nucleosyl)tetraphosphate + H2O = NTP + NMP, acting on guanosyl, xanthosyl, adenosyl and uridyl tetraphosphates.
What genes are involved in bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity?
Genes include ApaH in Pseudomonas aeruginosa and the genes encoding rat liver, human blood cell and human placental dinucleoside tetraphosphatases.
What is another name for this enzyme?
Common synonyms include Ap4A hydrolase, diadenosine 5',5'''-P1,P4-tetraphosphate asymmetrical hydrolase and dinucleoside tetraphosphatase.
Which substrates does the enzyme act on?
It acts on bis(5'-guanosyl)-, bis(5'-xanthosyl)-, bis(5'-adenosyl)- and bis(5'-uridyl)-tetraphosphate.
Is this enzyme found in humans?
Yes, dinucleoside tetraphosphatase has been purified from human blood cells and human placenta.
Why is bacterial ApaH important?
ApaH is a diadenosine tetraphosphatase that is crucial for Pseudomonas aeruginosa virulence.
How can I study this activity in the lab?
You can use enzyme activity assays with Ap4A, firefly luciferase substrate assays, affinity purification and immunological detection.
Can CRISPR be used to study GO:0004081?
Yes, CRISPR knockout, point mutation, knock-in and overexpression models can be used to dissect the function of the enzyme.
What diseases are linked to this activity?
The activity is linked to bacterial virulence and to nucleotide metabolism relevant to human blood and placental biology.
Conclusion
GO:0004081, bis(5'-nucleosyl)-tetraphosphatase (asymmetrical) activity, is a conserved molecular function that controls the hydrolysis of dinucleoside tetraphosphates such as Ap4A into NTP and NMP. Its enzymes have been characterized in rat tissues, human blood cells, human placenta, plants and bacteria, and the bacterial ApaH enzyme is important for virulence. Studying this activity with CRISPR models and biochemical assays will continue to clarify its roles in nucleotide homeostasis, stress signaling and infection.
References
- 1. Cameselle JC et al.. 1982. Bis-(5'-guanosyl) tetraphosphatase in rat tissues.. Biochem J 201(2):405-10 PMID: 6282267
- 2. Sillero MA et al.. 1997. 2',3'-dideoxynucleoside triphosphates (ddNTP) and di-2',3'-dideoxynucleoside tetraphosphates (ddNp4ddN) behave differently to the corresponding NTP and Np4N counterparts as substrates of firefly luciferase, dinucleoside tetraphosphatase and phosphodiesterases.. Biochim Biophys Acta 1334(2-3):191-9 PMID: 9101713
- 3. Cameselle JC et al.. 1984. Two low Km hydrolytic activities on dinucleoside 5',5"'-P1,P4-tetraphosphates in rat liver. Characterization as the specific dinucleoside tetraphosphatase and a phosphodiesterase I-like enzyme.. J Biol Chem 259(5):2879-85 PMID: 6321483
- 4. Jakubowski H et al.. 1983. Enzymes hydrolyzing ApppA and/or AppppA in higher plants. Purification and some properties of diadenosine triphosphatase, diadenosine tetraphosphatase, and phosphodiesterase from yellow lupin (Lupinus luteus) seeds.. J Biol Chem 258(16):9982-9 PMID: 6309793
- 5. Pinto RM et al.. 1991. Dinucleoside tetraphosphatase from human blood cells. Purification and characterization as a high specific activity enzyme recognized by an anti-rat tetraphosphatase antibody.. FEBS Lett 287(1-2):85-8 PMID: 1652465
- 6. Lazewska D et al.. 1993. Human placental (Asymmetrical) diadenosine 5',5'''-P1,P4-tetraphosphate hydrolase: purification to homogeneity and some properties.. Protein Expr Purif 4(1):45-51 PMID: 8381042
- 7. Costas MJ et al.. 1990. Purification to homogeneity of rat liver dinucleoside tetraphosphatase by affinity elution with adenosine 5'-tetraphosphate.. J Biochem Biophys Methods 21(1):25-33 PMID: 2170488
- 8. Pistoia G et al.. 2026. Structural and functional insights into Pseudomonas aeruginosa ApaH, a diadenosine tetraphosphatase crucial for bacterial virulence.. Protein Sci 35(9):e70781 PMID: 42640267
