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Literature summary for 1.11.1.11 extracted from
- Regulation of dual activity of ascorbate peroxidase 1 from Arabidopsis thaliana by conformational changes and posttranslational modifications (2021), Front. Plant Sci., 12, 678111 .
Activating Compound
| Activating Compound | Comment | Organism | Structure |
|---|---|---|---|
| additional information | S-nitrosylation and S-sulfhydration positively regulate the peroxidase activity, whereas no effects are observed on the chaperone function and the oligomeric status of AtAPX1 | Arabidopsis thaliana |
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| gene AtAPX1, recombinant expression of His6-tagged enzyme in Escherichia coli strain BL21(DE3) | Arabidopsis thaliana |
Inhibitors
| Inhibitors | Comment | Organism | Structure |
|---|---|---|---|
| additional information | tyrosine nitration has a negative impact. No effects are observed on the chaperone function and the oligomeric status of AtAPX1 | Arabidopsis thaliana |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| cytosol | - |
Arabidopsis thaliana | 5829 | - |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| Fe2+ | in the heme group | Arabidopsis thaliana |  |
Molecular Weight [Da]
| Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
|---|---|---|---|
| additional information | - |
the second size exclusion chromatography (SEC) fraction (F2) shows a band of proteins between 158 and 440 kDa, whereas the F3 fraction corresponding to the dimeric form of AtAPX1 appears below 158 kDa, representing the major peak in SEC analysis | Arabidopsis thaliana |
| 158000 | - |
about, dimeric recombinant enzyme, gel filtration | Arabidopsis thaliana |
| 440000 | - |
about, multimeric recombinant enzyme, gel filtration | Arabidopsis thaliana |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 2 L-ascorbate + H2O2 + 2 H+ | Arabidopsis thaliana | - |
L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? | |
| 2 L-ascorbate + H2O2 + 2 H+ | Arabidopsis thaliana Col-0 | - |
L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? | |
| additional information | Arabidopsis thaliana | AtAPX1 exhibits both peroxidase and chaperone activities | ? | - |
- |
|
| additional information | Arabidopsis thaliana Col-0 | AtAPX1 exhibits both peroxidase and chaperone activities | ? | - |
- |
|
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Arabidopsis thaliana | Q05431 | - |
- |
| Arabidopsis thaliana Col-0 | Q05431 | - |
- |
Posttranslational Modification
| Posttranslational Modification | Comment | Organism |
|---|---|---|
| S-nitrosylation | recombinant AtAPX1 protein is incubated with various concentrations (0-1 mM) of S-nitrosoglutathione (GSNO) at 25°C for 30 min in the dark to achieve S-nitrosylation of protein. S-nitrosylation and S-sulfhydration positively regulate the peroxidase activity, whereas no effects are observed on the chaperone function and the oligomeric status of AtAPX1. The GSNO-induced change in the activity of APX1 is not related to its oligomeric status, and NaHS-treated. In contrast to the negative regulation of the peroxidase activity of the SIN-1-treated protein, no effects on the chaperone activity are observed. Treatment with SIN-1 (peroxynitrite donor) does not cause any conformational changes eitherindicating that tyrosine nitration does not affect the structural status of AtAPX1 | Arabidopsis thaliana |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| recombinant His6-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, tag cleavage by thrombin, ultrafiltration, and gel filtration, again followed by ultrafiltration | Arabidopsis thaliana |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| seedling | - |
Arabidopsis thaliana | - |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 2 L-ascorbate + H2O2 + 2 H+ | - |
Arabidopsis thaliana | L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? | |
| 2 L-ascorbate + H2O2 + 2 H+ | - |
Arabidopsis thaliana Col-0 | L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? | |
| additional information | AtAPX1 exhibits both peroxidase and chaperone activities | Arabidopsis thaliana | ? | - |
- |
|
| additional information | APX enzymatic activity is measured by the decrease in absorbance at 290 nm due to the oxidation of ascorbate. The AtAPX1 protein shows a high chaperone activity as incubation of MDH with increasing amounts of AtAPX1 results in a concomitant decrease in the aggregation of MDH at 43°C. The aggregation of MDH is effectively suppressed at a subunit molar ratio of MDH to AtAPX1 of 1:2 | Arabidopsis thaliana | ? | - |
- |
|
| additional information | AtAPX1 exhibits both peroxidase and chaperone activities | Arabidopsis thaliana Col-0 | ? | - |
- |
|
| additional information | APX enzymatic activity is measured by the decrease in absorbance at 290 nm due to the oxidation of ascorbate. The AtAPX1 protein shows a high chaperone activity as incubation of MDH with increasing amounts of AtAPX1 results in a concomitant decrease in the aggregation of MDH at 43°C. The aggregation of MDH is effectively suppressed at a subunit molar ratio of MDH to AtAPX1 of 1:2 | Arabidopsis thaliana Col-0 | ? | - |
- |
|
Subunits
| Subunits | Comment | Organism |
|---|---|---|
| More | cytosol-type APX1 from Arabidopsis thaliana (AtAPX1) exists in multimeric forms ranging from dimeric to high-molecular-weight (HMW) complexes. The structure of AtAPX1 is regulated by heat and salt stresses, with both involved in the association and dissociation of complexes, respectively. No effects are observed on the chaperone function and the oligomeric status of AtAPX1 | Arabidopsis thaliana |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| APX | - |
Arabidopsis thaliana |
| ascorbate peroxidase 1 | - |
Arabidopsis thaliana |
| AtAPX1 | - |
Arabidopsis thaliana |
Temperature Optimum [°C]
| Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
|---|---|---|---|
| 22 | - |
ascorbate peroxidase activity, assay at room temperature | Arabidopsis thaliana |
| 43 | - |
chaperone activity, assay at | Arabidopsis thaliana |
pH Optimum
| pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|
| 7 | - |
ascorbate peroxidase activity, assay at | Arabidopsis thaliana |
| 8 | - |
chaperone activity, assay at | Arabidopsis thaliana |
Cofactor
| Cofactor | Comment | Organism | Structure |
|---|---|---|---|
| heme | - |
Arabidopsis thaliana | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| additional information | abiotic stress modulates structural changes in AtAPX1 protein and function in vivo. The recombinant AtAPX1 protein shows oligomeric forms besides the major dimeric form, and these different forms appear to play varying roles depending on the structural status of the protein. The protein exhibits a transition from dimeric units to HMW complexes under heat stress, whereas the HMW complexes are dissociated under salt stress | Arabidopsis thaliana |
| physiological function | the ascorbate-glutathione cycle is a pivotal antioxidant system involved in the regulation of H2O2 levels. Ascorbate peroxidase, being an important enzymatic antioxidant of this cycle, catalyzes the reduction of H2O2 to water using ascorbate as a specific electron donor. Cytosolic APX1 from Arabidopsis thaliana (AtAPX1) is crucial for tuning the regulation of H2O2, playing a key role in providing acclimation to a combination of heat and drought stress. Enzyme AtAPX1 plays a dual role behaving both as a regular peroxidase and a chaperone molecule, as the latter with the ability to inhibit the thermal aggregation of malate dehydrogenase (MDH), a heat-sensitive substrate. The dual activity of AtAPX1 is strongly related to its structural status. Abiotic stresses, such as heat and salt, regulate this dual function and structural status of AtAPX1 through the association and dissociation of APX proteins, respectively. The main dimeric form of the AtAPX1 protein shows the highest peroxidase activity, whereas the HMW form exhibits the highest chaperone activity. S-nitrosylation and S-sulfhydration positively regulate the peroxidase activity, whereas tyrosine nitration has a negative impact. No effects are observed on the chaperone function and the oligomeric status of AtAPX1 | Arabidopsis thaliana |
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