{"id":"2dd838c3-6621-50fe-afe1-c1c71b25e9dd","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-ppo-biomarker-response","predicate":"changed_redcell_pnpo_activity","statement":"Erythrocyte PPO activity and its activation coefficient responded to B2 supplementation and correlated with EGRAC; enzyme activity showed a dose response.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"ec57659c-da5a-5118-a5a3-0030f1acf05a","mechanism_event_label":"An enzyme used to activate B6 can also reveal aspects of B2 status because it needs an FMN cofactor.","subject":{"id":"86eb1eee-a8d1-539c-8c17-0911f69b6f1b","slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"},"object":{"id":"dda07945-be77-56d7-914b-61a1bffeca9e","slug":"erythrocyte-pnpo-activity","display_name":"Erythrocyte pyridoxamine/pyridoxine phosphate oxidase activity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"ec57659c-da5a-5118-a5a3-0030f1acf05a","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-ppo-biomarker-response-event","event_type":"observed_intervention","label":"An enzyme used to activate B6 can also reveal aspects of B2 status because it needs an FMN cofactor.","description":"Erythrocyte PPO activity and its activation coefficient responded to B2 supplementation and correlated with EGRAC; enzyme activity showed a dose response.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a01d08b9-a749-5bc3-934b-af0b35024b54","slug":"pnpo","display_name":"Pyridoxine 5-prime-phosphate oxidase / PNPO","entity_type_key":"protein"},"role":"assayed_enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c61e21f9-4393-52f8-a729-a4179f55ec7b","slug":"erythrocyte-pnpo-activation-coefficient","display_name":"Erythrocyte pyridoxamine phosphate oxidase activation coefficient","entity_type_key":"cellular_process"},"role":"assay_readout","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"34eee5dc-1157-5374-8f5c-ce7ec87156a4","slug":"erythrocyte-glutathione-reductase-activation-coefficient","display_name":"Erythrocyte glutathione reductase activation coefficient / EGRAC","entity_type_key":"cellular_process"},"role":"comparator","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"86eb1eee-a8d1-539c-8c17-0911f69b6f1b","slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"dda07945-be77-56d7-914b-61a1bffeca9e","slug":"erythrocyte-pnpo-activity","display_name":"Erythrocyte pyridoxamine/pyridoxine phosphate oxidase activity","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"A B6-activation enzyme provides a B2-sensitive functional assay.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Assay-development study using hemolysates from the RIBOFEM riboflavin intervention; same trial registration ISRCTN35811298.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Erythrocyte PPO activity with/without flavin activation; 2 and 4 mg/day supplementation arms. Not independent replication of RIBOFEM.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay-development analysis shares samples with RIBOFEM; not independent replication. Proposed utility in G6PD deficiency requires population-specific validation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Riboflavin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An enzyme used to activate B6 can also reveal aspects of B2 status because it needs an FMN cofactor.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b2-mushtaq2009] Erythrocyte pyridoxamine phosphate oxidase activity: a potential biomarker of riboflavin status? (2009). https://pubmed.ncbi.nlm.nih.gov/19740970/ DOI: 10.3945/ajcn.2009.28338","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human clinical setting","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"6976d57e-c848-5a56-9dce-d525da5845e5","evidence_kind":"source_excerpt","locator":"Lines 1653-1664","start_line":1653,"end_line":1664,"excerpt":"### b2-ppo-biomarker-response\nErythrocyte PPO activity and its activation coefficient responded to B2 supplementation and correlated with EGRAC; enzyme activity showed a dose response.\nCondition category: biomarker_context\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An enzyme used to activate B6 can also reveal aspects of B2 status because it needs an FMN cofactor.\norganism: Homo sapiens\ntissue_or_cell_type: Human clinical setting\nexperimental_model: Assay-development study using hemolysates from the RIBOFEM riboflavin intervention; same trial registration ISRCTN35811298.\nlimitations: Assay-development analysis shares samples with RIBOFEM; not independent replication. Proposed utility in G6PD deficiency requires population-specific validation.\nexposure: Erythrocyte PPO activity with/without flavin activation; 2 and 4 mg/day supplementation arms. Not independent replication of RIBOFEM.\ncross_nutrient: A B6-activation enzyme provides a B2-sensitive functional assay.\n[b2-mushtaq2009] Erythrocyte pyridoxamine phosphate oxidase activity: a potential biomarker of riboflavin status? (2009). https://pubmed.ncbi.nlm.nih.gov/19740970/ DOI: 10.3945/ajcn.2009.28338","model_system":"Assay-development study using hemolysates from the RIBOFEM riboflavin intervention; same trial registration ISRCTN35811298.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b2-mushtaq2009] Erythrocyte pyridoxamine phosphate oxidase activity: a potential biomarker of riboflavin status? (2009). https://pubmed.ncbi.nlm.nih.gov/19740970/ DOI: 10.3945/ajcn.2009.28338","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"4f7c9578-82bf-5e2d-b5c4-72a79fb4f6af","stable_key":"import-548ab9d6-3a9b-5bed-879c-17d03813b636","title":"Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"680cb6bc8249877f2410f551807f10d390fdd719014137d7414ba3420e29228d","revision_id":"7a61e299-908d-5372-860b-99ed190f9d7a","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}