id: P34105 gene_symbol: MAOX product_type: PROTEIN status: DRAFT taxon: id: NCBITaxon:3694 label: Populus trichocarpa description: Cytoplasmic NADP-dependent malic enzyme (NADP-ME; EC 1.1.1.40) that oxidatively decarboxylates (S)-malate to pyruvate with release of CO2 and generation of NADPH, requiring a divalent metal cation (Mg2+ or Mn2+); it also supports oxaloacetate decarboxylation. As a plant NADP-ME it links malate metabolism to pyruvate production and NADPH supply for biosynthesis and redox homeostasis. Deep-research literature (falcon) confirms the conserved enzyme identity and reaction but notes that the gene symbol "MAOX" could not be verified against a Populus trichocarpa name for P34105 in the accessible literature, so gene-symbol-specific claims are treated cautiously and the annotation is anchored to the UniProt accession and conserved NADP-ME family biology. alternative_records: - id: B9ILT5 relationship: REFERENCE_PROTEOME_EQUIVALENT reference_proteome: UP000006729 reviewed_on: '2026-10-19' reason: 'Retain P34105 as the primary Swiss-Prot accession. B9ILT5 at POPTR_018G086700 is the manually assessed reference-proteome counterpart: 584/591 identical residues with full ungapped coverage. Its seven differences are Y53F, H60Q, T84A, I204M, R251K, I413T, and Q457E. It is clearly separated from other malic-enzyme loci in the full-proteome search and global alignments. The original material is hybrid clone 064; sequence equivalence is assessed at the protein/locus level, not as literal identity or proof of parental origin.' evidence: - type: SEQUENCE_COMPARISON description: MMseqs2 searched all 77,340 sequences in UP000006729 (release 2026_03); global BLOSUM62 alignments were computed for every returned hit. B9ILT5 ranks first by global alignment score, with 98.8156% identity including gap columns, 100.0% query coverage and 100.0% target coverage. The saved candidate table and alignments retain competing matches and residue-level differences. The search is heuristic, and sequence similarity alone is not definitive genomic mapping. Identity over paired residues is 98.8156% (584/591); gap columns are excluded from this denominator. supported_by: - reference_id: file:POPTR/MAOX/MAOX-record-evidence.yaml supporting_text: |- query_length: 591 target_length: 591 alignment_columns: 591 identities: 584 mismatches: 7 gap_columns: 0 identity_percent: 98.8156 query_coverage_percent: 100.0 target_coverage_percent: 100.0 - type: PROTEOME_MEMBERSHIP description: Current UniProtKB and proteome records place B9ILT5, but not P34105, in reference proteome UP000006729. Both UniProt records use NCBITaxon:3694; source-organism qualifications are recorded separately. supported_by: - reference_id: file:POPTR/MAOX/MAOX-record-evidence.yaml supporting_text: |- reference_proteome: UP000006729 proteome_is_reference: true proteome_taxon_matches: true primary_in_reference_proteome: false alternative_in_reference_proteome: true - type: RECORD_HISTORY description: UniSave versions 101 (2015), 118 (2020), and 132 (2024) lack Proteomes cross-references. These dated samples support longstanding absence at those dates; they do not establish uninterrupted absence, a removal event, or UniProt's motivation. supported_by: - reference_id: file:POPTR/MAOX/MAOX-record-evidence.yaml supporting_text: |- sampled_history_versions: - 101 - 118 - 132 sampled_versions_with_proteome_links: [] - type: CURATION_CONTEXT description: The primary publication identifies the source material as Populus deltoides x Populus trichocarpa clone 064. ENA X56233 has inconsistent taxonomic text (P.deltoides in its description but P. trichocarpa in its organism field); the publication resolves the experimental source as a hybrid. supported_by: - reference_id: file:POPTR/MAOX/MAOX-record-evidence.yaml supporting_text: 'Organism: Populus deltoides x Populus trichocarpa, clone 064' existing_annotations: - term: id: GO:0004470 label: malic enzyme activity evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: Malic enzyme activity is correct but less specific than the NADP-dependent decarboxylating activity. action: MODIFY reason: UniProt specifies NADP-dependent malate dehydrogenase (decarboxylating) activity with EC 1.1.1.40, and deep-research literature defines this plant NADP-ME as an oxidative decarboxylase catalyzing L-malate + NADP+ to pyruvate, CO2, and NADPH; the more specific GO:0004473 captures the NADP cofactor and decarboxylating direction. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: is typically defined in plant biochemistry as an **oxidative decarboxylase** proposed_replacement_terms: - id: GO:0004473 label: malate dehydrogenase (decarboxylating) (NADP+) activity - term: id: GO:0004473 label: malate dehydrogenase (decarboxylating) (NADP+) activity evidence_type: IEA original_reference_id: GO_REF:0000120 qualifier: enables review: summary: NADP-dependent malate dehydrogenase decarboxylating activity is the core molecular function. action: ACCEPT reason: The UniProt catalytic reaction is (S)-malate plus NADP(+) to pyruvate, CO2, and NADPH, and deep-research literature independently confirms this conserved plant NADP-ME reaction with a divalent metal cation requirement. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: NADP-ME requires **NADP+** as electron acceptor and a **divalent cation**, typically **Mg2+ or Mn2+**, for activity. - term: id: GO:0005737 label: cytoplasm evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in review: summary: Cytoplasm localization is directly supported. action: ACCEPT reason: UniProt places MAOX in the cytoplasm. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm' - term: id: GO:0006108 label: malate metabolic process evidence_type: IEA original_reference_id: GO_REF:0000117 qualifier: involved_in review: summary: Malate metabolic process is appropriate for malic enzyme. action: ACCEPT reason: The enzyme directly consumes malate in the NADP-dependent decarboxylating reaction, and deep-research literature positions plant NADP-ME as the node linking malate metabolism to pyruvate production, CO2 release, and NADPH generation in central carbon metabolism. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: NADP-ME links **malate metabolism**, **pyruvate production**, **CO2 release**, and **NADPH generation** - term: id: GO:0008948 label: oxaloacetate decarboxylase activity evidence_type: IEA original_reference_id: GO_REF:0000116 qualifier: enables review: summary: Oxaloacetate decarboxylase activity is supported as an additional catalytic activity. action: ACCEPT reason: UniProt includes the oxaloacetate to pyruvate and CO2 reaction. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=oxaloacetate + H(+) = pyruvate + CO2; - term: id: GO:0016616 label: oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: The broad oxidoreductase term should be replaced by the specific NADP-dependent malic enzyme activity. action: MODIFY reason: UniProt provides the specific malate dehydrogenase (decarboxylating) NADP-dependent reaction, and deep-research literature confirms NADP+ (not NAD+) as the electron acceptor for this enzyme, so the specific GO:0004473 better captures the cofactor and reaction than the broad NAD-or-NADP oxidoreductase grouping term. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: NADP-ME requires **NADP+** as electron acceptor and a **divalent cation**, typically **Mg2+ or Mn2+**, for activity. proposed_replacement_terms: - id: GO:0004473 label: malate dehydrogenase (decarboxylating) (NADP+) activity - term: id: GO:0051287 label: NAD binding evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: NAD binding is structurally supported, but NADP binding is the better primary cofactor term for this NADP-dependent malic enzyme. action: MODIFY reason: UniProt feature annotations include NAD(+) binding positions and NAD(P)-binding domains, but the reviewed protein name, keyword, and primary malic enzyme reaction specify NADP(+); this MODIFY therefore targets the primary catalytic cofactor rather than denying structural NAD binding. supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["FT:BINDING"] supporting_text: FT BINDING 335..351 - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["FT:BINDING"] supporting_text: FT BINDING 192 - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: NADP-ME requires **NADP+** as electron acceptor and a **divalent cation**, typically **Mg2+ or Mn2+**, for activity. proposed_replacement_terms: - id: GO:0050661 label: NADP binding references: - id: file:POPTR/MAOX/MAOX-record-evidence.yaml title: Compact archived record and sequence evidence for P34105 - id: GO_REF:0000002 title: Gene Ontology annotation through association of InterPro records with GO terms findings: - statement: GO_REF:0000002 supplied one or more source GOA annotations reviewed in this file. - id: GO_REF:0000120 title: Combined Automated Annotation using Multiple IEA Methods findings: - statement: GO_REF:0000120 supplied one or more source GOA annotations reviewed in this file. - id: GO_REF:0000044 title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping findings: - statement: GO_REF:0000044 supplied one or more source GOA annotations reviewed in this file. - id: GO_REF:0000117 title: Electronic Gene Ontology annotations created by ARBA machine learning models findings: - statement: GO_REF:0000117 supplied one or more source GOA annotations reviewed in this file. - id: GO_REF:0000116 title: Automatic GO annotation based on Rhea mapping findings: - statement: GO_REF:0000116 supplied one or more source GOA annotations reviewed in this file. - id: file:POPTR/MAOX/MAOX-uniprot.txt title: UniProtKB reviewed entry for MAOX findings: - record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; reference_section_type: OTHER - record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm' reference_section_type: OTHER - id: file:POPTR/MAOX/MAOX-goa.tsv title: QuickGO GOA annotations for MAOX findings: - statement: GOA rows supplied the existing_annotations reviewed in this file. - id: file:POPTR/MAOX/MAOX-deep-research-falcon.md title: Falcon deep research report for Populus trichocarpa NADP-dependent malic enzyme (P34105) findings: - supporting_text: catalyzes **L-malate + NADP+ → pyruvate + CO2 + NADPH** and requires a **divalent cation (Mg2+ or Mn2+)** reference_section_type: OTHER - supporting_text: NADP-ME requires **NADP+** as electron acceptor and a **divalent cation**, typically **Mg2+ or Mn2+**, for activity. reference_section_type: OTHER - supporting_text: is typically defined in plant biochemistry as an **oxidative decarboxylase** reference_section_type: OTHER - supporting_text: NADP-ME links **malate metabolism**, **pyruvate production**, **CO2 release**, and **NADPH generation** reference_section_type: OTHER - supporting_text: In plants, NADP-ME isoforms occur mainly in the **cytosol** and **plastids/chloroplasts**. reference_section_type: OTHER - supporting_text: no paper explicitly maps the symbol reference_section_type: OTHER - supporting_text: AKG administration suppressed NADP-ME activity in leaves reference_section_type: OTHER core_functions: - description: Catalyzes cytoplasmic NADP-dependent oxidative decarboxylation of malate to pyruvate, CO2, and NADPH. molecular_function: id: GO:0004473 label: malate dehydrogenase (decarboxylating) (NADP+) activity directly_involved_in: - id: GO:0006108 label: malate metabolic process locations: - id: GO:0005737 label: cytoplasm supported_by: - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:CATALYTIC ACTIVITY"] supporting_text: Reaction=(S)-malate + NADP(+) = pyruvate + CO2 + NADPH; - reference_id: file:POPTR/MAOX/MAOX-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm' - reference_id: file:POPTR/MAOX/MAOX-deep-research-falcon.md supporting_text: NADP-ME links **malate metabolism**, **pyruvate production**, **CO2 release**, and **NADPH generation** proposed_new_terms: [] suggested_questions: - question: What physiological context drives Populus cytosolic NADP-malic enzyme activity, particularly in roots? - question: Is the gene symbol "MAOX" the accepted Populus trichocarpa name for UniProt P34105, and to which Populus genome locus does P34105 map among the multiple cytosolic and plastidic NADP-ME isoforms? suggested_experiments: - description: Measure NADP-malic enzyme activity and malate/pyruvate/NADPH pools in MAOX perturbation lines under root stress conditions. experiment_type: targeted functional assay - description: Confirm cytosolic versus plastidic localization of the P34105 isoform in Populus trichocarpa by fluorescent-protein fusion or subcellular fractionation, to resolve the family-level localization ambiguity. experiment_type: subcellular localization