ahpC encodes AhpC, the typical 2-Cys peroxiredoxin (AhpC/Prx1 subfamily) subunit of the E. coli AhpC/AhpF alkyl hydroperoxide reductase. AhpC is cytosolic and can assemble into ring-shaped decamers of dimers; its oligomeric distribution depends on redox and experimental conditions. Its peroxidatic cysteine (Cys47) attacks hydrogen peroxide or an organic hydroperoxide, releasing water or the corresponding alcohol, and the resulting sulfenic acid condenses with the resolving cysteine (Cys166) of the partner subunit to form an intersubunit disulfide. The flavoprotein AhpF reduces this disulfide with electrons from NADH, so the AhpC/AhpF pair carries out NADH-dependent hydroperoxide reduction. Because AhpC acts efficiently at very low peroxide concentrations, it is the main scavenger of endogenously generated hydrogen peroxide during aerobic growth, while catalase HPI (KatG) dominates at high peroxide levels. ahpCF is part of the OxyR peroxide-stress regulon, and loss of ahpC causes hypersensitivity to alkyl hydroperoxides.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004601 peroxidase activity | IGI PMID:11717276 Alkyl hydroperoxide reductase is the primary scavenger of en... | MODIFY | Summary: Seaver and Imlay showed genetically, with katG and katE, that the AhpCF system scavenges H2O2 in catalase-null cells. AhpC is the peroxide-reducing subunit, so peroxidase activity is correct but general. Reason: Peroxidase activity is true for AhpC, but the review already supports the more specific descendant GO:0051920 peroxiredoxin activity (thiol-based, AhpC/Prx1 family, Cys47/Cys166 intersubunit disulfide). Per the refinement rule, the general parent is refined to the peroxiredoxin term that the gene already carries. The genetic evidence itself is sound. Proposed replacements: peroxiredoxin activity Supporting Evidence: PMID:11717276 Thus, Ahp provides the scavenging activity that persists in catalase null mutants. file:ECOLI/ahpC/ahpC-uniprot.txt Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. |
| GO:0005515 protein binding | IPI PMID:15004283 Proteomic analysis of thioredoxin-targeted proteins in Esche... | REMOVE | Summary: AhpC co-purified with tagged thioredoxin 1 (TrxA) in a tandem affinity proteomic screen of thioredoxin-associated proteins. Reason: The association is plausible for a thiol peroxidase that can form mixed disulfides, and removal does not mean the interaction is false. But generic protein binding says nothing about AhpC function, and the abstract supports no more informative molecular function for AhpC. Supporting Evidence: PMID:15004283 We also found a number of proteins associated with thioredoxin that either participate directly (SodA, HPI, and AhpC) or have key regulatory functions (Fur and AcnB) in the detoxification of the cell. |
| GO:0005515 protein binding | IPI PMID:20806779 The protein-free IANUS peptide array uncovers interaction si... | REMOVE | Summary: The peptidyl-prolyl isomerase parvulin 10 (Par10, PpiC) binds AhpC; the AhpC Asp125-Pro126 bond was identified as a Par10 substrate. Reason: The interaction is experimentally supported, and removal does not mean it is false, but it describes AhpC as a prolyl-isomerization substrate of Par10 rather than an AhpC molecular function. No more informative AhpC molecular-function term is supported by the paper. Supporting Evidence: PMID:20806779 parvulin 10 (Par10), an abundant Escherichia coli peptidyl prolyl cis/trans isomerase (PPIase), physically interacts with the alkyl hydroperoxide reductase subunit C (AhpC) in bacterial cell extracts |
| GO:0005737 cytoplasm | IDA PMID:7499381 Thioredoxin-linked "thiol peroxidase" from periplasmic space... | MODIFY | Summary: Cha et al. fractionated E. coli and found the 24-kDa AhpC mainly in the cell interior, unlike periplasmic thiol peroxidase Tpx. Reason: Cytoplasm is correct but general. AhpC is a soluble decameric enzyme and the gene already carries several cytosol (GO:0005829) annotations (IDA PMID:15911532, IDA PMID:18304323, HDA PMID:16858726, IBA), so the localization is refined to cytosol. Proposed replacements: cytosol Supporting Evidence: PMID:7499381 The 20-kDa protein resides mainly in the periplasmic space of E. coli, whereas the 24-kDa AhpC resides mainly in the matrix. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | MODIFY | Summary: UniProt subcellular-location mapping of AhpC to the cytoplasm. Reason: Correct but general; refined to cytosol, which the gene already carries from direct fractionation and proteomic evidence. Consistent with the IDA cytoplasm row above. Proposed replacements: cytosol Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt SUBCELLULAR LOCATION: Cytoplasm |
| GO:0005829 cytosol | HDA PMID:16858726 A complexomic study of Escherichia coli using two-dimensiona... | ACCEPT | Summary: AhpC was recovered among cytosolic homomultimeric complexes in a blue-native/SDS-PAGE complexome survey. Reason: Consistent with the soluble decameric peroxiredoxin and with the other cytosol rows. Supporting Evidence: PMID:16858726 the cytosolic and membrane protein complexes of Escherichia coli were separated. |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT places cytosolic activity at the ancestral typical 2-Cys peroxiredoxin node; E. coli AhpC is one of the experimentally grounded descendants. Reason: AhpC is a soluble cytosolic enzyme, and its own cytosol evidence is among the sources of this IBA, which is expected rather than circular. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt SUBCELLULAR LOCATION: Cytoplasm |
| GO:0005829 cytosol | IDA PMID:15911532 Localization, annotation, and comparison of the Escherichia ... | ACCEPT | Summary: Large-scale fractionation proteomics assigned AhpC to the cytosolic fraction. Reason: Direct fractionation evidence consistent with the biochemistry of the soluble AhpC decamer. Supporting Evidence: PMID:15911532 2,160 were annotated and assigned to the cytosol, periplasm, inner membrane, and outer membrane by biochemical fractionation |
| GO:0005829 cytosol | IDA PMID:18304323 Protein abundance profiling of the Escherichia coli cytosol. | ACCEPT | Summary: The curated cytosol annotation comes from a cytosolic abundance-profiling study; its target-specific supplementary entry is not independently verified here. Reason: Cytosolic localization agrees with independent biochemical localization and soluble-enzyme evidence. The experimental location is supported, although the target-specific supplementary table could not be verified. Supporting Evidence: PMID:7499381 whereas the 24-kDa AhpC resides mainly in the matrix. |
| GO:0006979 response to oxidative stress | IBA GO_REF:0000033 | MODIFY | Summary: Peroxide removal by AhpC is a direct effector step of the oxidative stress response, and ahpCF is part of the OxyR peroxide-stress regulon. Reason: AhpC directly removes hydrogen peroxide and alkyl hydroperoxides in the OxyR-regulated AhpCF system. Refine this broad oxidative-stress term to both supported descendants: response to hydrogen peroxide and response to alkyl hydroperoxide (the latter already carried by this gene). The two substrate classes justify multiple replacements rather than retaining only their broad common ancestor. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN000073874 SUPPORTS TRANSFER The listed PAINT node supports the inherited oxidative-stress role, with experimental grounding on E. coli AhpC itself. This refinement retains the positive claim while representing both target-supported peroxide response descendants; no node misplacement or donor insufficiency is alleged. Proposed replacements: response to hydrogen peroxide response to alkyl hydroperoxide Supporting Evidence: PMID:11717276 Mutants that lack both Ahp and catalase could not scavenge H 2 O 2 . PMID:2649484 ahp-1 was isolated in a wild-type background and is dependent on oxyR, a positive regulator of defenses against oxidative stress. |
| GO:0006979 response to oxidative stress | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO mapping from the AhpC family signature. Reason: AhpC directly removes hydrogen peroxide and alkyl hydroperoxides in the OxyR-regulated AhpCF system. Refine this broad oxidative-stress term to both supported descendants: response to hydrogen peroxide and response to alkyl hydroperoxide (the latter already carried by this gene). The two substrate classes justify multiple replacements rather than retaining only their broad common ancestor. Proposed replacements: response to hydrogen peroxide response to alkyl hydroperoxide Supporting Evidence: PMID:11717276 Mutants that lack both Ahp and catalase could not scavenge H 2 O 2 . PMID:2649484 ahp-1 was isolated in a wild-type background and is dependent on oxyR, a positive regulator of defenses against oxidative stress. |
| GO:0006979 response to oxidative stress | NAS PMID:28270505 Essential role of the flexible linker on the conformational ... | MODIFY | Summary: Kamariah et al. describe AhpC/AhpF as an antioxidant system that detoxifies reactive oxygen species. Reason: AhpC directly removes hydrogen peroxide and alkyl hydroperoxides in the OxyR-regulated AhpCF system. Refine this broad oxidative-stress term to both supported descendants: response to hydrogen peroxide and response to alkyl hydroperoxide (the latter already carried by this gene). The two substrate classes justify multiple replacements rather than retaining only their broad common ancestor. Proposed replacements: response to hydrogen peroxide response to alkyl hydroperoxide Supporting Evidence: PMID:11717276 Mutants that lack both Ahp and catalase could not scavenge H 2 O 2 . PMID:2649484 ahp-1 was isolated in a wild-type background and is dependent on oxyR, a positive regulator of defenses against oxidative stress. |
| GO:0008379 obsolete thioredoxin peroxidase activity | IBA GO_REF:0000033 | MODIFY | Summary: The ancestral typical 2-Cys peroxiredoxin node carries peroxide-reducing activity, but the term is obsolete and its thioredoxin donor does not describe E. coli AhpC, which is reduced by AhpF. Reason: GOA labels GO:0008379 obsolete; the source identifier is retained. The peroxiredoxin chemistry inherited from the PAINT node is correct for AhpC, so the row is refined to the donor-independent GO:0051920 peroxiredoxin activity rather than to GO:0140824 thioredoxin-dependent peroxiredoxin activity, because the physiological reductant of E. coli AhpC is the dedicated flavoprotein AhpF. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN000073874 Β· PTN000073874 SOURCE STALE OR MISSING The ancestral 2-Cys peroxiredoxin chemistry transfers correctly to AhpC, but the transferred term is obsolete and its thioredoxin donor does not apply to E. coli AhpC, whose dedicated reductase is AhpF. Proposed replacements: peroxiredoxin activity Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily. PMID:28270505 AhpF is a flexible multidomain protein that enables a series of electron transfers among the redox centers by accepting reducing equivalents from NADH. |
| GO:0009321 alkyl hydroperoxide reductase complex | IDA PMID:25372677 Structure, mechanism and ensemble formation of the alkylhydr... | ACCEPT | Summary: Dip et al. solved the EcAhpC decamer and EcAhpF structures and measured AhpF binding to the AhpC ring, defining the AhpC/AhpF ensemble. Reason: GO:0009321 is the appropriate complex term for the AhpC/AhpF system and matches the AhpF review, which accepts the same rows. Supporting Evidence: PMID:25372677 These studies suggest a novel overall mechanistic model of AhpR as a hydroperoxide scavenger, in which the dimeric, extended AhpF prefers complex formation with the AhpC ring to accelerate the catalytic activity |
| GO:0009321 alkyl hydroperoxide reductase complex | IPI PMID:25372677 Structure, mechanism and ensemble formation of the alkylhydr... | ACCEPT | Summary: Isothermal titration calorimetry demonstrated direct AhpF binding to AhpC. Reason: Same claim as the IDA row from the same study; consistent with AhpF. Supporting Evidence: PMID:25372677 its binding to EcAhpC was demonstrated by isothermal titration calorimetry. |
| GO:0009970 cellular response to sulfate starvation | IDA PMID:8774726 Analysis of global responses by protein and peptide fingerpr... | UNDECIDED | Summary: The experimental sulfate-starvation annotation cites a two-dimensional electrophoresis study; the curated UniProt record also reports repression by sulfate or cysteine. Reason: The cached abstract describes eight sulfate-starvation-induced proteins but does not expose the AhpC-specific experiments or the basis of the process annotation. Full publisher recovery failed. Expression regulation is compatible with a response, and absence of a sulfur-assimilation reaction does not disprove this broader response term. Leave the experimental assertion unresolved rather than overriding the curator from incomplete text. Supporting Evidence: PMID:8774726 A set of 8 proteins (SSI, sulfate-starvation-induced proteins) was observed by comparative two-dimensional electrophoresis to be induced when Escherichia coli were grown using compounds other than sulfate or cysteine as the sole sulfur source. |
| GO:0016020 membrane | HDA PMID:16858726 A complexomic study of Escherichia coli using two-dimensiona... | UNDECIDED | Summary: A high-throughput complexome study is the source of the membrane annotation; its cached abstract does not expose the AhpC-specific fraction or complex. Reason: Independent evidence places AhpC mainly in the soluble cytosolic pool, but this does not exclude a peripheral or condition-specific membrane association. The full target-specific result could not be recovered. Neither contamination nor a meaningful membrane-associated pool is established by the accessible evidence, so the experimental localization remains unresolved. Supporting Evidence: PMID:7499381 whereas the 24-kDa AhpC resides mainly in the matrix. |
| GO:0016209 antioxidant activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO antioxidant activity from the AhpC/TSA domain. Reason: True but general. GO:0051920 peroxiredoxin activity is an is_a descendant of antioxidant activity and is already annotated to AhpC, so the row is refined to it. Proposed replacements: peroxiredoxin activity Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily. |
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO oxidoreductase activity from the AhpC/TSA domain. Reason: True but uninformative; refined to the specific descendant GO:0051920 peroxiredoxin activity already carried by the gene. Proposed replacements: peroxiredoxin activity Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. |
| GO:0016684 oxidoreductase activity, acting on peroxide as acceptor | IMP PMID:7644465 Cloning of an organic solvent-resistance gene in Escherichia... | MODIFY | Summary: A G142V ahpC mutant selected for tetralin resistance reduced tetralin hydroperoxide to the alcohol three times faster than wild type, directly linking AhpC to hydroperoxide reduction. Reason: The evidence is sound and shows that the ahpC product reduces an organic hydroperoxide. The term is a general parent of GO:0051920 peroxiredoxin activity, which the gene carries and which names the thiol-based mechanism, so the row is refined to it. Proposed replacements: peroxiredoxin activity Supporting Evidence: PMID:7644465 The ahpC mutant was found to have an activity that was three times that of the wild type in reducing tetralin hydroperoxide to 1,2,3,4-tetrahydro-1-naphthol. |
| GO:0018106 peptidyl-histidine phosphorylation | IDA PMID:35636362 Selective enrichment tandem Ξ²-elimination assisted strategy ... | UNDECIDED | Summary: The cited study reports high-confidence N-phosphoproteins in E. coli lysates, but the available abstract contains no AhpC-specific assay. Reason: Full publisher recovery failed, so the exact evidence behind this experimental process annotation cannot be inspected. If AhpC is only a phosphorylated substrate, that alone would not establish that it performs the phosphorylation step; however, the abstract does not establish that this is all the curator saw. The available evidence therefore leaves AhpC participation unresolved and does not establish kinase activity. Supporting Evidence: PMID:35636362 N-phosphoproteins from E. coli lysates were analyzed by EnaBe approach and 16 N-phosphoproteins with high confidence were identified. |
| GO:0019290 siderophore biosynthetic process | IMP PMID:23042987 AhpC is required for optimal production of enterobactin by E... | UNDECIDED | Summary: In E. coli BW25113, ahpC deletion lowers DHB and enterobactin production and impairs growth under iron limitation. Extra entC, DHB, shikimate or aromatic end products suppress aspects of the phenotype. A resolving-cysteine mutant separates peroxide resistance from the iron phenotype. Reason: Full PMID:23042987 establishes a specific physiological connection to early enterobactin production. It does not identify the biochemical step performed by AhpC. The cysteine-mutant experiments show that peroxide-detoxification activity alone is insufficient, so a simple indirect peroxide-protection explanation is not established either. The authors consider chorismate availability and direct or indirect FMN reduction for chorismate synthesis, while noting that EntC itself has no known redox cofactor. The precise biosynthetic participation remains unresolved; neither a confident rejection nor a new FMN-reductase assertion is warranted. Supporting Evidence: PMID:23042987 These data suggested that AhpC affected the activity of EntC or the availability of the chorismate substrate. url:https://pmc.ncbi.nlm.nih.gov/articles/PMC3510565/ the peroxidase activity of AhpC is not sufficient for AhpC to participate in cellular iron metabolism. |
| GO:0033194 response to hydroperoxide | IMP PMID:7733872 Mammalian antioxidant protein complements alkylhydroperoxide... | MODIFY | Summary: An E. coli strain lacking the AhpC (C22) subunit is sensitive to alkyl hydroperoxide, and the mouse peroxiredoxin Aop1 rescues resistance. Reason: Loss of the hydroperoxide-reducing enzyme sensitizes cells to hydroperoxide, and complementation by a homologous peroxiredoxin supports that the protection comes from peroxide reduction. The evidence is specific to alkyl hydroperoxide, so the general parent is refined to its child GO:0033195 response to alkyl hydroperoxide, which the gene already carries (IMP, PMID:2649484). Proposed replacements: response to alkyl hydroperoxide Supporting Evidence: PMID:7733872 Expression of the Aop1 gene product in E. coli deficient in the C22-subunit gene rescued resistance of the bacteria to alkylhydroperoxide. |
| GO:0033195 response to alkyl hydroperoxide | IMP PMID:2649484 An alkyl hydroperoxide reductase induced by oxidative stress... | ACCEPT | Summary: Deletion of ahp in E. coli and S. typhimurium caused hypersensitivity to cumene hydroperoxide, complemented by cloned ahp. Reason: Classic genetic evidence that the AhpC/AhpF reductase protects against alkyl hydroperoxides, its founding substrate class. Supporting Evidence: PMID:2649484 Deletions of ahp obtained in both S. typhimurium and E. coli resulted in hypersensitivity to killing by cumene hydroperoxide (an alkyl hydroperoxide) |
| GO:0042744 hydrogen peroxide catabolic process | IBA GO_REF:0000033 | ACCEPT | Summary: AhpC directly reduces H2O2 to water and is the primary scavenger of endogenous H2O2 in E. coli. Reason: Core process; AhpC's own experimental evidence is among the descendant sources of this IBA, as expected. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Is the primary scavenger for endogenously generated hydrogen peroxides. |
| GO:0042744 hydrogen peroxide catabolic process | IDA PMID:28270505 Essential role of the flexible linker on the conformational ... | ACCEPT | Summary: Purified EcAhpC with EcAhpF and NADH decomposed H2O2 in xylenol orange and NADH-consumption assays. Reason: Direct biochemical evidence for H2O2 breakdown by the AhpC/AhpF system. Supporting Evidence: PMID:28270505 Peroxide decomposition catalyzed by Ec AhpC in the presence of WT Ec AhpF or linker mutants were measured using the ferrous oxidation xylenol assay |
| GO:0042802 identical protein binding | IPI PMID:16858726 A complexomic study of Escherichia coli using two-dimensiona... | KEEP AS NON CORE | Summary: AhpC was recovered as a homomultimeric complex in native gel complexome analysis. Reason: Self-association is real (disulfide-linked dimers assembling into a decameric ring) and structurally important for peroxiredoxin activity, but it is a quaternary-structure property rather than the function of AhpC. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Homodimer; disulfide-linked, upon oxidation. 5 homodimers assemble to form a ring-like decamer |
| GO:0042802 identical protein binding | IPI PMID:24561554 The binary protein-protein interaction landscape of Escheric... | KEEP AS NON CORE | Summary: AhpC self-interaction was detected in the genome-scale E. coli binary interaction screen. Reason: Consistent with the known AhpC homodimer/decamer; same non-core self-association claim as the row above. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Homodimer; disulfide-linked, upon oxidation. 5 homodimers assemble to form a ring-like decamer |
| GO:0045454 cell redox homeostasis | IBA GO_REF:0000033 | ACCEPT | Summary: By removing H2O2 generated during aerobic metabolism, AhpC keeps intracellular peroxide below the level that activates OxyR. Reason: Removing metabolically generated peroxide directly maintains the cellular redox environment: loss of Ahp permits accumulation of the endogenous inducer of OxyR (PMID:11717276). This is a core homeostatic role of the enzyme, consistent with the PAINT inference, rather than a peripheral phenotype. The term is not an ontology ancestor of cellular oxidant detoxification that should simply be replaced by it. Supporting Evidence: PMID:11717276 These data demonstrate that in wild-type cells Ahp rather than catalase is the primary scavenger of an endogenous inducer of the OxyR regulon. |
| GO:0051920 peroxiredoxin activity | IEA GO_REF:0000002 | ACCEPT | Summary: AhpC is a typical 2-Cys peroxiredoxin: peroxidatic Cys47 forms an intersubunit disulfide with resolving Cys166 after peroxide reduction. Reason: This is the best existing term for the reaction AhpC itself catalyzes, independent of which protein supplies the reducing equivalents. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily. file:ECOLI/ahpC/ahpC-uniprot.txt Interchain (with C-166); in linked form file:ECOLI/ahpC/ahpC-uniprot.txt Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. |
| GO:0098869 cellular oxidant detoxification | IEA GO_REF:0000120 | ACCEPT | Summary: AhpC detoxifies hydrogen peroxide and organic hydroperoxides inside the cell. Reason: Core process directly performed by AhpC's peroxide-reducing activity; matches the process assigned to the AhpF annoton in the AhpC/AhpF module. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt Plays a role in cell protection against oxidative stress by detoxifying peroxides. PMID:11717276 In sum, E. coli does indeed generate substantial H 2 O 2 , but damage is averted by the scavenging activity of Ahp. |
| GO:0102039 NADH-dependent peroxiredoxin activity | EXP PMID:11717276 Alkyl hydroperoxide reductase is the primary scavenger of en... | ACCEPT | Summary: Seaver and Imlay showed in vivo that the AhpC/AhpF system is the primary scavenger of endogenous H2O2 and that its turnover is limited by NADH supply. The NADH-dependent reaction (EC 1.11.1.26) is a property of the AhpC/AhpF pair: AhpC reduces the peroxide and AhpF consumes NADH. Reason: Native E. coli genetics and purified EcAhpC/EcAhpF reconstitution support the coupled NADH-dependent hydroperoxide-reduction reaction. AhpC performs peroxide reduction while AhpF oxidizes NADH and regenerates AhpC; this annotation is accepted for the experimentally established enzyme component without asserting that the isolated subunit performs both half-reactions. AhpC is the peroxide-reducing component of the NADH-driven AhpCF system. Supporting Evidence: file:ECOLI/ahpC/ahpC-uniprot.txt The disulfide is subsequently reduced by AhpF. PMID:11717276 This arrangement is reasonable because the cell cannot provide enough NADH for Ahp to rapidly degrade large amounts of H 2 O 2 . PMID:28270505 AhpF is a flexible multidomain protein that enables a series of electron transfers among the redox centers by accepting reducing equivalents from NADH. |
| GO:0102039 NADH-dependent peroxiredoxin activity | IEA GO_REF:0000120 | ACCEPT | Summary: Electronic transfer of EC 1.11.1.26 / RHEA:62628 from the AhpC UniProt entry. Reason: Native E. coli genetics and purified EcAhpC/EcAhpF reconstitution support the coupled NADH-dependent hydroperoxide-reduction reaction. AhpC performs peroxide reduction while AhpF oxidizes NADH and regenerates AhpC; this annotation is accepted for the experimentally established enzyme component without asserting that the isolated subunit performs both half-reactions. AhpC is the peroxide-reducing component of the NADH-driven AhpCF system. Supporting Evidence: PMID:28270505 NADH-dependent peroxidase activity was measured in the presence of Ec AhpC, H 2 O 2 , and WT Ec AhpF |
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Download this section (compressed HTML)Q: How should the coupled AhpC/AhpF NADH-dependent peroxiredoxin reaction be represented alongside the experimentally separated peroxide-reduction and donor-regeneration activities in GO-CAM, while preserving the native donor-partner specificity?
Q: What biochemical contribution of AhpC supports early enterobactin production and distinguishes the resolving-cysteine mutant iron phenotype from peroxide resistance: maintenance of chorismate supply, a separate redox reaction, or another interaction?
Experiment: Reconstitute chorismate synthesis and EntC-dependent DHB production with defined flavin cofactors, AhpC/AhpF, wild-type and resolving-cysteine AhpC variants, and a matched independent peroxide-scavenging control. Quantify reduced FMN, chorismate and DHB separately, and test whether the in vitro result explains the BW25113 iron-limitation phenotype.
Hypothesis: AhpC may support chorismate supply through a redox contribution distinguishable from peroxide scavenging; the existing cysteine-mutant results do not establish the relevant reaction.
Type: Biochemical reconstitution and matched genetic complementation
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