{"id":"9a95d837-e799-5524-9fe3-d2822a788db5","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-rat-epimerase","predicate":"converts","statement":"Rat liver cytosol contained activity converting myo-inositol to D-chiro-inositol.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"5c271df9-feb3-5125-8820-5b2d45c5669c","mechanism_event_label":"One stereoisomer can be converted into another in this rat tissue preparation.","subject":{"id":"65abfe35-d1a6-568c-baee-2d929a2a2ec0","slug":"rat-myo-dci-epimerase-activity","display_name":"Myo-to-D-chiro-inositol epimerase activity in rat cytosol","entity_type_key":"cellular_process"},"object":{"id":"50afe95c-f542-5511-ba8b-c2ff2b037977","slug":"myo-inositol","display_name":"Myo-inositol","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"5c271df9-feb3-5125-8820-5b2d45c5669c","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-rat-epimerase-event","event_type":"biochemical_relationship","label":"One stereoisomer can be converted into another in this rat tissue preparation.","description":"Rat liver cytosol contained activity converting myo-inositol to D-chiro-inositol.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b687b65c-726f-551a-846b-fc488629669c","slug":"d-chiro-inositol","display_name":"D-chiro-inositol","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"65abfe35-d1a6-568c-baee-2d929a2a2ec0","slug":"rat-myo-dci-epimerase-activity","display_name":"Myo-to-D-chiro-inositol epimerase activity in rat cytosol","entity_type_key":"cellular_process"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"50afe95c-f542-5511-ba8b-c2ff2b037977","slug":"myo-inositol","display_name":"Myo-inositol","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/inositol-research/12051772.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\", \"start_char\": 0, \"end_char\": 2218, \"text_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Radiotracer conversion and cytosolic enzyme assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Diabetic rat versus controls; reduced pyridine-nucleotide cofactors","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The molecular identity of the activity was not established here. A later mouse stable-isotope study found no myo-to-D-chiro conversion; the research disagreement is recorded separately. Do not invent a human epimerase gene or infer a universal supplement ratio.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Inositol research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"inositol","display_name":"Inositol (stereoisomer family)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Goto-Kakizaki and Wistar rats","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"One stereoisomer can be converted into another in this rat tissue preparation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[ino-p12051772] Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls. (2002). https://pubmed.ncbi.nlm.nih.gov/12051772/ DOI: 10.1016/s0006-291x(02)00313-3","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Liver, muscle, kidney and adipose preparations","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"feca03df-0579-5160-922f-e0eea2705896","evidence_kind":"source_excerpt","locator":"Lines 1172-1183","start_line":1172,"end_line":1183,"excerpt":"### ino-rat-epimerase\nRat liver cytosol contained activity converting myo-inositol to D-chiro-inositol.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: One stereoisomer can be converted into another in this rat tissue preparation.\norganism: Goto-Kakizaki and Wistar rats\ntissue_or_cell_type: Liver, muscle, kidney and adipose preparations\nexperimental_model: Radiotracer conversion and cytosolic enzyme assays\nlimitations: The molecular identity of the activity was not established here. A later mouse stable-isotope study found no myo-to-D-chiro conversion; the research disagreement is recorded separately. Do not invent a human epimerase gene or infer a universal supplement ratio.\nexposure: Diabetic rat versus controls; reduced pyridine-nucleotide cofactors\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/12051772.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\", \"start_char\": 0, \"end_char\": 2218, \"text_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\"}\n[ino-p12051772] Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls. (2002). https://pubmed.ncbi.nlm.nih.gov/12051772/ DOI: 10.1016/s0006-291x(02)00313-3","model_system":"Radiotracer conversion and cytosolic enzyme assays","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [ino-p12051772] Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls. (2002). https://pubmed.ncbi.nlm.nih.gov/12051772/ DOI: 10.1016/s0006-291x(02)00313-3","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"d590c659-b774-50e6-9f1d-aff61d5f7c9c","stable_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (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":"f7adbcedad647d5f8a3cc9e46bfa515e83c508be9c2a4e9d59c5f5dfb0667d53","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[{"id":"c1e0e5c9-4b45-5d61-be60-1b524dc90104","title":"Reported myo-to-D-chiro conversion versus no conversion detected by mouse isotope tracing","kind":"contradiction","status":"open","why":"Rat radiotracer/cytosolic studies reported myo-to-chiro epimerase activity, while the later dietary-control and stable-isotope study detected no endogenous DCI production or conversion from labeled myo-inositol in mice. The latter paper explicitly questions identification of chiro-inositol in earlier tracer work. Different species and assays may contribute but do not yet resolve the disagreement.","resolution":"Preserve the reported rat activity and its NADH/NADPH dependence alongside the negative mouse tracer findings. Do not represent a universally established mammalian epimerase, assign an unidentified human gene, or derive an optimal supplement ratio. Compare dietary contamination, tracer fate, stereoisomer identification and tissue specificity before proposing a resolution.","created_at":"2026-09-17 17:44:25","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/c1e0e5c9-4b45-5d61-be60-1b524dc90104","sides":[{"conflict_id":"c1e0e5c9-4b45-5d61-be60-1b524dc90104","ordinal":0,"label":"One stereoisomer can be converted into another in this rat tissue preparation.","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","start_line":1172,"end_line":1183,"quote":"### ino-rat-epimerase\nRat liver cytosol contained activity converting myo-inositol to D-chiro-inositol.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: One stereoisomer can be converted into another in this rat tissue preparation.\norganism: Goto-Kakizaki and Wistar rats\ntissue_or_cell_type: Liver, muscle, kidney and adipose preparations\nexperimental_model: Radiotracer conversion and cytosolic enzyme assays\nlimitations: The molecular identity of the activity was not established here. A later mouse stable-isotope study found no myo-to-D-chiro conversion; the research disagreement is recorded separately. Do not invent a human epimerase gene or infer a universal supplement ratio.\nexposure: Diabetic rat versus controls; reduced pyridine-nucleotide cofactors\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/12051772.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\", \"start_char\": 0, \"end_char\": 2218, \"text_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\"}\n[ino-p12051772] Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls. (2002). https://pubmed.ncbi.nlm.nih.gov/12051772/ DOI: 10.1016/s0006-291x(02)00313-3","source_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","source_title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (2026-09-17)","claim_ids":["9a95d837-e799-5524-9fe3-d2822a788db5"]},{"conflict_id":"c1e0e5c9-4b45-5d61-be60-1b524dc90104","ordinal":1,"label":"Reduced niacin-derived cofactors supported the observed conversion.","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","start_line":1185,"end_line":1196,"quote":"### ino-epimerase-nadh\nThe rat cytosolic epimerase assay required NADH and NADPH for full activity.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Reduced niacin-derived cofactors supported the observed conversion.\norganism: Goto-Kakizaki and Wistar rats\ntissue_or_cell_type: Liver, muscle, kidney and adipose preparations\nexperimental_model: Radiotracer conversion and cytosolic enzyme assays\nlimitations: The molecular identity of the activity was not established here. A later mouse stable-isotope study found no myo-to-D-chiro conversion; the research disagreement is recorded separately. Do not invent a human epimerase gene or infer a universal supplement ratio.\nexposure: Diabetic rat versus controls; reduced pyridine-nucleotide cofactors\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/12051772.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\", \"start_char\": 0, \"end_char\": 2218, \"text_sha256\": \"28ae1225b489898738997d2376ab09857f017314086979032d3ad907299a1154\"}\n[ino-p12051772] Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls. (2002). https://pubmed.ncbi.nlm.nih.gov/12051772/ DOI: 10.1016/s0006-291x(02)00313-3","source_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","source_title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (2026-09-17)","claim_ids":["5e92f6d1-a26a-589a-9d1d-8f1b8d4ffe3b"]},{"conflict_id":"c1e0e5c9-4b45-5d61-be60-1b524dc90104","ordinal":2,"label":"This study did not reproduce the proposed endogenous conversion route in its mouse experiments.","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","start_line":1224,"end_line":1235,"quote":"### ino-dci-no-conversion\nIn the mouse tracer experiments, labeled D-chiro-inositol was not detected after heavy-water exposure or deuterated myo-inositol administration.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This study did not reproduce the proposed endogenous conversion route in its mouse experiments.\norganism: Rats and mice; conversion tracing in mice\ntissue_or_cell_type: Gastrointestinal absorption, plasma and excreta\nexperimental_model: Dietary balance, GC-MS and stable-isotope tracing\nlimitations: Failure to detect conversion in mice does not exclude all human or isolated-tissue activity. Isotope strategy, chemical identification, species and dietary DCI contamination may contribute to disagreement with earlier radiotracer reports.\nexposure: Defined diets, heavy water and deuterated myo-inositol/DCI\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/19586572.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"7c6e57e631fef5921afd04f75718024d5b14ca525460e2c96275a4fc320c3b26\", \"start_char\": 0, \"end_char\": 1544, \"text_sha256\": \"7c6e57e631fef5921afd04f75718024d5b14ca525460e2c96275a4fc320c3b26\"}\n[ino-p19586572] d- chiro-Inositol is absorbed but not synthesised in rodents. (2009). https://pubmed.ncbi.nlm.nih.gov/19586572/ DOI: 10.1017/s0007114509990456","source_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","source_title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (2026-09-17)","claim_ids":["b6efa232-8791-536a-874a-a67395471de8"]},{"conflict_id":"c1e0e5c9-4b45-5d61-be60-1b524dc90104","ordinal":3,"label":"The measured pool depended strongly on dietary input in this experiment.","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","start_line":1250,"end_line":1261,"quote":"### ino-dci-diet-depletion\nDCI in mouse plasma, stool and urine fell to very low levels on the pinitol/DCI-depleted diet, whereas levels remained stable on standard chow.\nCondition category: nutrient_deficiency\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The measured pool depended strongly on dietary input in this experiment.\norganism: Rats and mice; conversion tracing in mice\ntissue_or_cell_type: Gastrointestinal absorption, plasma and excreta\nexperimental_model: Dietary balance, GC-MS and stable-isotope tracing\nlimitations: Failure to detect conversion in mice does not exclude all human or isolated-tissue activity. Isotope strategy, chemical identification, species and dietary DCI contamination may contribute to disagreement with earlier radiotracer reports.\nexposure: Defined diets, heavy water and deuterated myo-inositol/DCI\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/19586572.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"7c6e57e631fef5921afd04f75718024d5b14ca525460e2c96275a4fc320c3b26\", \"start_char\": 0, \"end_char\": 1544, \"text_sha256\": \"7c6e57e631fef5921afd04f75718024d5b14ca525460e2c96275a4fc320c3b26\"}\n[ino-p19586572] d- chiro-Inositol is absorbed but not synthesised in rodents. (2009). https://pubmed.ncbi.nlm.nih.gov/19586572/ DOI: 10.1017/s0007114509990456","source_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","source_title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (2026-09-17)","claim_ids":["bdd49f81-6000-5f9a-9b13-1e93ae6a94ac"]}]}],"corrections":[],"research":null}