identifier: traitmech:000076 label: oxidase activity definition: A physiological enzyme-activity phenotype in which a cell produces a terminal respiratory oxidase (notably cytochrome c oxidase); it is the basis of the diagnostic oxidase test. definition_source: DOI:10.3390/microorganisms10050926 trait_category: PHYSIOLOGY term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000059 synonyms: - synonym_text: oxidase-positive synonym_type: RELATED_SYNONYM source: DOI:10.3390/microorganisms10050926 evidence: - reference: DOI:10.3390/microorganisms10050926 notes: Hederstedt reviews bacterial cytochrome c oxidase, the terminal respiratory oxidase detected by the oxidase test. - reference: DOI:10.1089/ars.2020.8039 notes: Borisov et al. review cytochrome bd-family terminal oxidases of prokaryotic respiratory chains. canonical_examples: - taxon_id: NCBITaxon:287 taxon_label: Pseudomonas aeruginosa note: "cytochrome-c-oxidase positive" reference: PMID:28542449 - taxon_id: NCBITaxon:485 taxon_label: Neisseria gonorrhoeae note: "oxidase-positive" reference: PMID:20154126 causal_graphs: - graph_id: oxidase_activity_terminal_oxidase title: Terminal respiratory oxidase reducing oxygen description: Evidence-backed causal sketch linking a terminal respiratory oxidase to reduction of molecular oxygen, the basis of the oxidase test. nodes: - node_id: oxidase_activity_trait label: oxidase activity node_type: TRAIT grounding: traitmech:000076 description: Possession of a terminal respiratory oxidase. - node_id: cytochrome_c_oxidase label: cytochrome c oxidase node_type: GENE_OR_PROTEIN description: Terminal oxidase of the respiratory chain. grounding: UniProtKB:A0A075NZN5 - node_id: cytochrome_c_oxidase_function label: cytochrome-c oxidase activity node_type: MOLECULAR_FUNCTION grounding: GO:0004129 description: Reduction of molecular oxygen using ferrocytochrome c. - node_id: molecular_oxygen label: molecular oxygen node_type: CHEMICAL grounding: CHEBI:15379 description: Terminal electron acceptor reduced to water. - node_id: family_a_cytochrome_c_oxidase label: family A cytochrome c oxidase node_type: GENE_OR_PROTEIN description: Canonical heme-copper terminal oxidase with heme a/a3 and CuA/CuB centers, the classic oxidase-test target. - node_id: reduced_cytochrome_c label: reduced cytochrome c node_type: CHEMICAL description: Ferrocytochrome c, the physiological electron donor to cytochrome c oxidase. grounding: CHEBI:16928 - node_id: cua_center label: CuA center node_type: CHEMICAL description: Dicopper electron-entry center in subunit II of family A cytochrome c oxidase. - node_id: heme_a label: heme a node_type: CHEMICAL description: Low-spin heme A cofactor relaying electrons within family A cytochrome c oxidase. grounding: CHEBI:24479 - node_id: heme_a3_cub_binuclear_center label: heme a3-CuB binuclear center node_type: CHEMICAL description: Catalytic dioxygen-reduction site of heme-copper oxidases. - node_id: cua_cub_copper_centers label: CuA/CuB copper centers node_type: CHEMICAL description: The three copper atoms (dicopper CuA and CuB) of family A cytochrome c oxidase. - node_id: carbon_monoxide label: carbon monoxide node_type: CHEMICAL description: Gaseous ligand that potently inhibits heme-copper terminal oxidases. grounding: CHEBI:17245 edges: - subject: cytochrome_c_oxidase predicate: enables object: cytochrome_c_oxidase_function description: Cytochrome c oxidase carries out terminal oxidase activity. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: Hederstedt reviews bacterial cytochrome c oxidase. predicate_id: RO:0002327 - subject: cytochrome_c_oxidase_function predicate: consumes object: molecular_oxygen description: The terminal oxidase reduces molecular oxygen to water. evidence: - reference: DOI:10.1089/ars.2020.8039 notes: Borisov et al. review terminal oxidases that reduce O2. predicate_id: biolink:consumes - subject: cytochrome_c_oxidase predicate: enables object: oxidase_activity_trait description: Possession of a terminal oxidase confers the oxidase-activity phenotype. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: Supports the oxidase-test basis. predicate_id: RO:0002327 - subject: reduced_cytochrome_c predicate: donates electrons to object: cua_center description: Reduced cytochrome c donates electrons to the CuA center of subunit II. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: 'Hederstedt: "reduced cytochrome c donates electrons to the CuA center in subunit II."' predicate_id: METPO:2007403 - subject: cua_center predicate: transfers electrons to object: heme_a description: The CuA center relays electrons to low-spin heme a. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: 'Hederstedt: electrons pass from CuA "then to low-spin heme a."' predicate_id: METPO:2007403 - subject: heme_a3_cub_binuclear_center predicate: reduces object: molecular_oxygen description: The heme a3-CuB binuclear center reduces molecular oxygen to water. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: 'Hederstedt: "the dioxygen reduction site (heme a3 + CuB)."' predicate_id: METPO:2000017 - subject: family_a_cytochrome_c_oxidase predicate: has cofactor object: heme_a description: Family A cytochrome c oxidase contains two heme A prosthetic groups (heme a and heme a3). evidence: - reference: DOI:10.3390/microorganisms10050926 notes: 'Hederstedt: "contains two heme A prosthetic groups (heme a and heme a3)."' - subject: family_a_cytochrome_c_oxidase predicate: has cofactor object: cua_cub_copper_centers description: Family A cytochrome c oxidase carries three copper atoms in CuA and CuB centers. evidence: - reference: DOI:10.3390/microorganisms10050926 notes: 'Hederstedt: "three copper atoms (CuA is di-copper in subunit II; CuB in subunit I)."' - subject: carbon_monoxide predicate: inhibits object: cytochrome_c_oxidase_function description: Carbon monoxide is a potent inhibitor of heme-copper cytochrome c oxidase activity. evidence: - reference: DOI:10.3390/ijms26062809 notes: 'Borisov & Forte 2025: "CO is a potent inhibitor of heme-copper cytochrome c oxidase (Ki ~0.3 uM)."' predicate_id: RO:0002212 curation_history: - timestamp: '2026-06-04T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate PHYSIOLOGY trait (oxidase activity) from literature research to fill the enzyme-activity-phenotype gap. llm_assisted: true - timestamp: '2026-06-08T13:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (terminal oxidase reducing O2) with GO/CHEBI node groundings and RO/biolink predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-14T05:51:47Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:A0A075NZN5×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 6 evidence-backed generic edges (7 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:15Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 4 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2007403×2, METPO:2000017×1, RO:0002212×1). llm_assisted: true - timestamp: '2026-06-24T17:21:20Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:17245×1). llm_assisted: true - timestamp: '2026-06-24T17:23:35Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 2 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:16928×1, CHEBI:24479×1). llm_assisted: true