{"id":"6ecf1302-5700-5773-b009-70c3ac5c478d","stable_key":"18100170-a014-51c3-adeb-9dab4162b8cc:metal-competition","predicate":"context_dependent_observation","statement":"Other tested metals competed for zinc binding to purified FTS; this is not a demonstrated dietary-metal antagonism in vivo.","claim_class":"mechanistic","status":"source_recorded","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"95e30e46-81b6-5c3c-9bb8-66d18e7d2a3a","mechanism_event_label":"Other tested metals competed for zinc binding to purified FTS; this is not a demonstrated dietary-metal antagonism in vivo.","subject":{"id":"c42b9296-be70-516b-b473-9111a42618fb","slug":"thymulin-zinc-binding","display_name":"Purified FTS zinc-binding affinity and metal-dependent conformation","entity_type_key":"cellular_process"},"object":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"95e30e46-81b6-5c3c-9bb8-66d18e7d2a3a","stable_key":"18100170-a014-51c3-adeb-9dab4162b8cc:metal-competition-event","event_type":"biochemical_relationship","label":"Other tested metals competed for zinc binding to purified FTS; this is not a demonstrated dietary-metal antagonism in vivo.","description":"A separate binding study reported an apparent zinc dissociation constant of **(5 ± 2) × 10⁻⁷ M at pH 7.5** and no detectable binding below pH 6 under its assay conditions. Other tested metals competed for binding. These are purified-system measurements, not a threshold for dietary intake, plasma zinc or thymulin failure inside a patient. They make pH and competing ligands relevant experimental variables. [Zinc-binding study, 1984](https://pubmed.ncbi.nlm.nih.gov/6538097/)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"c42b9296-be70-516b-b473-9111a42618fb","slug":"thymulin-zinc-binding","display_name":"Purified FTS zinc-binding affinity and metal-dependent conformation","entity_type_key":"cellular_process"},"role":"tested factor","stoichiometry":null,"state_label":"as reported","sequence_order":0,"notes":""},{"entity":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"role":"measured outcome","stoichiometry":null,"state_label":"mixed","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary bibliographic record and abstract checked; full methods/figures not comprehensively reviewed.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified FTS metal-binding system; identities/concentrations of competitors not extracted in the reviewed reference.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Other tested metals competed for zinc binding to purified FTS; this is not a demonstrated dietary-metal antagonism in vivo.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Studies on the zinc binding site to the serum thymic factor. | 1984 | DOI 10.1016/0304-4165(84)90116-8 | PMID 6538097 | https://pubmed.ncbi.nlm.nih.gov/6538097/","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference lines 25-25; exact primary location described in quoted passage where extracted.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"33c2de6e-e2bf-5d16-a9c3-2c895404635a","evidence_kind":"source_excerpt","locator":"Lines 25-25","start_line":25,"end_line":25,"excerpt":"A separate binding study reported an apparent zinc dissociation constant of **(5 ± 2) × 10⁻⁷ M at pH 7.5** and no detectable binding below pH 6 under its assay conditions. Other tested metals competed for binding. These are purified-system measurements, not a threshold for dietary intake, plasma zinc or thymulin failure inside a patient. They make pH and competing ligands relevant experimental variables. [Zinc-binding study, 1984](https://pubmed.ncbi.nlm.nih.gov/6538097/)","model_system":"Purified FTS metal-binding system; identities/concentrations of competitors not extracted in the reviewed reference.","directness":"reported_statement","verification_status":"source_recorded","notes":"Exact excerpt of the retained AI-assisted reviewed reference; primary sources are cited in primary_references and access scope is retained. Not a verbatim quotation from a primary paper.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"e1871d49-9c6b-547b-a1bb-6e2b9270ca89","stable_key":"import-18100170-a014-51c3-adeb-9dab4162b8cc","title":"Thymulin: detailed mechanisms of action (reviewed 3 October 2026)","document_type":"imported_text","citation_label":"Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication.","file_path":"","sha256":"6e8ed0d7a5e23fc822f2ab418e0c4fb2411c01fcaa330039e8d7d93218cacc88","revision_id":"8c0e3449-9bbd-57c0-bb5e-de83f044f2ac","review_status":"source_recorded","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}