ARGAH2 is a manganese-dependent arginase/agmatinase with demonstrated arginine-to-ornithine/urea and agmatine-to-putrescine activities. It supplies most measured arginase activity in the examined germinating seedlings and can participate with arginine decarboxylase in putrescine production. Mitochondrial matrix targeting and a chloroplast pool have been demonstrated in distinct expression systems. Phosphatidic acid binds the enzyme and stimulates arginase activity in vitro; effects on defense and amino-acid pools depend on tissue and treatment.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000050 urea cycle | IEA GO_REF:0000041 | KEEP AS NON CORE | Summary: Arginase supplies the arginine-cleavage arm of ornithine/arginine recycling. Reason: The current GO urea-cycle definition does not require ureotelic nitrogen excretion. Arginase chemistry plus the native ornithine/citrulline/arginine recycling observed in OAT mutants supports a contextual cycle annotation. Catabolic nitrogen mobilization is the core function; this does not assert mammalian hepatic detoxification or a quantitatively demonstrated closed cycle in every tissue. Supporting Evidence: PMID:18419821 Accumulation of Cit indicated that Orn and Arg were metabolised after uptake, most likely by enzymes of the urea cycle. file:ARATH/ARGAH2/ARGAH2-uniprot.txt Reaction=L-arginine + H2O = urea + L-ornithine; |
| GO:0004053 arginase activity | IBA GO_REF:0000033 | ACCEPT | Summary: ARGAH hydrolyzes arginine to ornithine and urea. Reason: Direct recombinant ARGAH2 activity and substrate kinetics in PMID:35752016 substantiate arginine hydrolysis independently of inferred family membership; native mutant activity and yeast complementation in PMID:18567826 corroborate it. Supporting Evidence: PMID:35752016 PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. |
| GO:0004053 arginase activity | IDA PMID:22188168 Overexpression of arginase in Arabidopsis thaliana influence... | ACCEPT | Summary: ARGAH hydrolyzes arginine to ornithine and urea. Reason: Direct recombinant ARGAH2 activity and substrate kinetics in PMID:35752016 substantiate arginine hydrolysis independently of inferred family membership; native mutant activity and yeast complementation in PMID:18567826 corroborate it. Supporting Evidence: PMID:35752016 PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. |
| GO:0004053 arginase activity | IDA PMID:35752016 Phosphatidic acid binds to and stimulates the activity of AR... | ACCEPT | Summary: ARGAH hydrolyzes arginine to ornithine and urea. Reason: Direct recombinant ARGAH2 activity and substrate kinetics in PMID:35752016 substantiate arginine hydrolysis independently of inferred family membership; native mutant activity and yeast complementation in PMID:18567826 corroborate it. Supporting Evidence: PMID:35752016 PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. |
| GO:0004053 arginase activity | IEA GO_REF:0000120 | ACCEPT | Summary: ARGAH hydrolyzes arginine to ornithine and urea. Reason: Direct recombinant ARGAH2 activity and substrate kinetics in PMID:35752016 substantiate arginine hydrolysis independently of inferred family membership; native mutant activity and yeast complementation in PMID:18567826 corroborate it. Supporting Evidence: PMID:35752016 PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. |
| GO:0004053 arginase activity | ISS GO_REF:0000024 | ACCEPT | Summary: ARGAH hydrolyzes arginine to ornithine and urea. Reason: Direct recombinant ARGAH2 activity and substrate kinetics in PMID:35752016 substantiate arginine hydrolysis independently of inferred family membership; native mutant activity and yeast complementation in PMID:18567826 corroborate it. Supporting Evidence: PMID:35752016 PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. |
| GO:0005739 mitochondrion | HDA PMID:18385124 Heterogeneity of the mitochondrial proteome for photosynthet... | ACCEPT | Summary: Mitochondrial residence is a supported core localization. Reason: The target Arabidopsis ARGAH2 construct colocalizes with a mitochondrial matrix marker in tobacco BY-2 cells, and selective permeabilization supports an internal mitochondrial pool (PMID:18567826). This establishes mitochondrial residence while the more specific matrix location is added separately. It does not exclude a distinct chloroplast pool under other conditions. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) |
| GO:0005739 mitochondrion | HDA PMID:25293756 A proteomic strategy for global analysis of plant protein co... | ACCEPT | Summary: Mitochondrial residence is a supported core localization. Reason: The target Arabidopsis ARGAH2 construct colocalizes with a mitochondrial matrix marker in tobacco BY-2 cells, and selective permeabilization supports an internal mitochondrial pool (PMID:18567826). This establishes mitochondrial residence while the more specific matrix location is added separately. It does not exclude a distinct chloroplast pool under other conditions. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: Mitochondrial residence is a supported core localization. Reason: The target Arabidopsis ARGAH2 construct colocalizes with a mitochondrial matrix marker in tobacco BY-2 cells, and selective permeabilization supports an internal mitochondrial pool (PMID:18567826). This establishes mitochondrial residence while the more specific matrix location is added separately. It does not exclude a distinct chloroplast pool under other conditions. Independent target localization supports the transferred organelle claim without treating the computational row as a new direct experiment. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) |
| GO:0005739 mitochondrion | ISM GO_REF:0000122 | ACCEPT | Summary: Mitochondrial residence is a supported core localization. Reason: The target Arabidopsis ARGAH2 construct colocalizes with a mitochondrial matrix marker in tobacco BY-2 cells, and selective permeabilization supports an internal mitochondrial pool (PMID:18567826). This establishes mitochondrial residence while the more specific matrix location is added separately. It does not exclude a distinct chloroplast pool under other conditions. Independent target localization supports the transferred organelle claim without treating the computational row as a new direct experiment. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) |
| GO:0005829 cytosol | HDA PMID:28887381 Global Analysis of Membrane-associated Protein Oligomerizati... | UNDECIDED | Summary: Cytosolic residence is unresolved despite detection in proteomic fractions. Reason: The PMID:28887381 S1 target entry uses a mitochondrial location assignment; fraction recovery and the study-wide cytosolic classification do not by themselves resolve a native cytosolic pool versus released organellar enzyme. The independently demonstrated matrix pool does not rule out a second pool, so the HDA annotation remains open. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) file:ARATH/DELTA-OAT/DELTA-OAT-source-analysis/README.md The S1 Mapp sheet lists all four target proteins as mitochondrion. |
| GO:0006560 L-proline metabolic process | IMP PMID:22188168 Overexpression of arginase in Arabidopsis thaliana influence... | UNDECIDED | Summary: A direct role of ARGAH2 in proline metabolism is unresolved. Reason: PMID:22188168 reports amino-acid pool changes after overexpression or simultaneous arginase silencing, but accessible text does not resolve the proline-specific experiment. Native OAT genetics limits a simple arginaseβOATβproline synthesis model, without ruling out nutritional or indirect effects. Full target-specific flux or mechanistic evidence is needed before accepting this process assignment. Supporting Evidence: PMID:22188168 Overexpression of arginase resulted in changes in amino acid accumulation, while polyamine levels remained largely unaffected. PMID:18419821 These findings indicate that Ξ΄OAT does not contribute significantly to stress-induced Pro biosynthesis in vivo during salt stress. |
| GO:0006591 ornithine metabolic process | IMP PMID:22188168 Overexpression of arginase in Arabidopsis thaliana influence... | MODIFY | Summary: Arginine hydrolysis directly produces ornithine. Reason: The catalytic reaction is a biosynthetic source of free ornithine. The metabolite changes in PMID:22188168 do not imply an ornithine-consuming activity; refine the broad metabolic term to the existing reaction direction. Proposed replacements: ornithine biosynthetic process Supporting Evidence: file:ARATH/ARGAH2/ARGAH2-uniprot.txt Reaction=L-arginine + H2O = urea + L-ornithine; |
| GO:0008783 agmatinase activity | IBA GO_REF:0000033 | ACCEPT | Summary: ARGAH also catalyzes agmatine hydrolysis to putrescine. Reason: PMID:28716421 provides target-specific functional evidence, not merely an arginase/agmatinase family name. Both paralogs rescue ODC-deficient yeast together with ADC2; purified coupled assays specifically examine ARGAH2. ARGAH1 activity is therefore supported by complementation, not assigned ARGAH2 kinetic parameters. Supporting Evidence: PMID:28716421 Transformation of Arabidopsis thaliana ADC2, and any of the arginases from A. thaliana (ARGAH1, or ARGHA2) or the soybean gene Glyma.03g028000 (GmARGAH) into a yeast strain deficient in ODC, fully complemented the mutant phenotype. PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0008783 agmatinase activity | IDA PMID:28716421 Dual functioning of plant arginases provides a third route f... | ACCEPT | Summary: ARGAH also catalyzes agmatine hydrolysis to putrescine. Reason: PMID:28716421 provides target-specific functional evidence, not merely an arginase/agmatinase family name. Both paralogs rescue ODC-deficient yeast together with ADC2; purified coupled assays specifically examine ARGAH2. ARGAH1 activity is therefore supported by complementation, not assigned ARGAH2 kinetic parameters. Supporting Evidence: PMID:28716421 Transformation of Arabidopsis thaliana ADC2, and any of the arginases from A. thaliana (ARGAH1, or ARGHA2) or the soybean gene Glyma.03g028000 (GmARGAH) into a yeast strain deficient in ODC, fully complemented the mutant phenotype. PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0008783 agmatinase activity | IEA GO_REF:0000120 | ACCEPT | Summary: ARGAH also catalyzes agmatine hydrolysis to putrescine. Reason: PMID:28716421 provides target-specific functional evidence, not merely an arginase/agmatinase family name. Both paralogs rescue ODC-deficient yeast together with ADC2; purified coupled assays specifically examine ARGAH2. ARGAH1 activity is therefore supported by complementation, not assigned ARGAH2 kinetic parameters. Supporting Evidence: PMID:28716421 Transformation of Arabidopsis thaliana ADC2, and any of the arginases from A. thaliana (ARGAH1, or ARGHA2) or the soybean gene Glyma.03g028000 (GmARGAH) into a yeast strain deficient in ODC, fully complemented the mutant phenotype. PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009445 putrescine metabolic process | IMP PMID:22188168 Overexpression of arginase in Arabidopsis thaliana influence... | MODIFY | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Proposed replacements: putrescine biosynthetic process Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009446 putrescine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009446 putrescine biosynthetic process | IDA PMID:28716421 Dual functioning of plant arginases provides a third route f... | ACCEPT | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009446 putrescine biosynthetic process | IDA PMID:28716421 Dual functioning of plant arginases provides a third route f... | ACCEPT | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009446 putrescine biosynthetic process | IEA GO_REF:0000117 | ACCEPT | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009446 putrescine biosynthetic process | IGI PMID:28716421 Dual functioning of plant arginases provides a third route f... | ACCEPT | Summary: The agmatinase reaction directly supplies putrescine. Reason: Both Arabidopsis paralogs support an ADC-dependent route in yeast, and purified ARGAH2 has direct coupled biochemical support. This establishes synthetic capacity, while its fractional contribution to endogenous plant putrescine flux and stress-dependent dominance remain unresolved. The older simultaneous-silencing study is corroborative metabolic context, not proof that every tissue depends on this route. Supporting Evidence: PMID:28716421 In vitro assays using purified recombinant enzymes of AtADC1 and AtARGAH2 were used to show that these enzymes can function in concert to convert arginine to agmatine and putrescine. |
| GO:0009507 chloroplast | IEA GO_REF:0000044 | ACCEPT | Summary: ARGAH2 has a chloroplast-targeted pool in transient expression assays. Reason: PMID:28716421 independently reports Nicotiana leaf targeting of the Arabidopsis ARGAH/ADC constructs. This supports a chloroplast pool, alongside the separately demonstrated mitochondrial pool; physiological partitioning and condition dependence remain unquantified. Supporting Evidence: PMID:28716421 showed that these proteins are localized to the chloroplast. |
| GO:0009570 chloroplast stroma | IDA PMID:28716421 Dual functioning of plant arginases provides a third route f... | UNDECIDED | Summary: The chloroplast pool is supported, but stromal resolution could not be independently verified. Reason: The available PMID:28716421 abstract specifies chloroplast localization, while the full paper could not be retrieved through publisher and repository searches. The existing stromal IDA may be valid, but the inspected text cannot distinguish stroma from other chloroplast subcompartments. Retain broad chloroplast localization while leaving this more precise assertion open. Supporting Evidence: PMID:28716421 showed that these proteins are localized to the chloroplast. |
| GO:0046872 metal ion binding | IEA GO_REF:0000002 | MODIFY | Summary: Refine generic metal binding to the catalytic manganese cofactor. Reason: Direct AtARGAH1 structures and conserved curated Mn-binding residues in ARGAH2 support this specificity. Cobalt-affinity screen annotations remain separately unresolved and do not establish a physiological cobalt cofactor. Proposed replacements: manganese ion binding Supporting Evidence: file:ARATH/ARGAH2/ARGAH2-uniprot.txt Note=Binds 2 manganese ions per subunit. |
| GO:0050832 defense response to fungus | IMP PMID:22188168 Overexpression of arginase in Arabidopsis thaliana influence... | KEEP AS NON CORE | Summary: ARGAH2 overexpression reduces susceptibility to Botrytis in the tested assay. Reason: The abstract directly states the native transgenic resistance phenotype; simultaneous silencing did not increase susceptibility. Retain this contextual defense association without asserting an essential antifungal function or direct pathogen toxicity. Supporting Evidence: PMID:22188168 Arabidopsis plants overexpressing the arginase gene were less susceptible to B. cinerea, whereas silencing lines remained as susceptible as the wild type. |
| GO:0050897 cobalt ion binding | HDA PMID:20018591 Divalent metal ions in plant mitochondria and their role in ... | UNDECIDED | Summary: The metal-affinity screen suggests association, but target-specific direct binding remains unresolved. Reason: Full PMID:20018591 uses metal-loaded IMAC on mitochondrial extracts and identifies multiple proteins from enriched gel bands. This does not make metal binding false or require a physiological cofactor role; however, the exact target rows in supplemental S3/S4 could not be recovered, and direct binding versus co-purification is unresolved. Preserve the experimental annotation pending target-specific evidence rather than replacing it with the enzyme cofactor. Supporting Evidence: PMID:20018591 The interaction of metal ions with mitochondrial proteins that might be responsible for these toxic effects was investigated in vitro using IMAC to trap metal-binding proteins. |
| GO:0005759 mitochondrial matrix | IDA PMID:18567826 Arginase-negative mutants of Arabidopsis exhibit increased n... | NEW | Summary: The tagged Arabidopsis arginase is experimentally localized to the mitochondrial matrix in tobacco BY-2 cells. Reason: The target-protein construct colocalizes with the E1Ξ² matrix marker and is inaccessible to anti-myc antibody after selective plasma-membrane permeabilization with digitonin. Together these identify the mitochondrial interior. Add the subcompartment alongside retained mitochondrial organelle rows, without claiming native Arabidopsis fractionation or excluding other pools. Supporting Evidence: file:ARATH/ARGAH1/ARGAH1-source-analysis/README.md Therefore, each protein was actually localized in the mitochondrial interior (matrix) |
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Download this section (compressed HTML)Q: What fraction of native arginine and agmatine turnover is carried by each paralog in particular tissues and stress conditions?
Q: How is mitochondrial versus plastid partitioning controlled, and is a stable cytosolic pool present?
Experiment: Combine endogenous tagging with organelle fractionation controls and isotope-labeled substrate/product measurements in single and complemented mutants to distinguish compartment-specific enzyme pools and pathway flux.
Type: native localization and isotope flux
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