{"id":"5b0031f8-8184-5ca1-a435-348853efeb3d","stable_key":"18100170-a014-51c3-adeb-9dab4162b8cc:complex-structure","predicate":"reported_relationship","statement":"NMR in DMSO-d6 identified 1:1 and 1:2 zinc-peptide complexes; Ser4 and the Asn9 terminal carboxylate coordinated zinc, with Ser8 participating in the 1:1 complex.","claim_class":"identity","status":"source_recorded","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"71ea34cb-2168-58e8-b4c7-77954e34944a","mechanism_event_label":"NMR in DMSO-d6 identified 1:1 and 1:2 zinc-peptide complexes; Ser4 and the Asn9 terminal carboxylate coordinated zinc, with Ser8 participating in the 1:1 complex.","subject":{"id":"9bac7a31-4b5b-59f2-8dad-39269ddbb8b1","slug":"fts-peptide","display_name":"Zinc-free FTS nonapeptide component","entity_type_key":"peptide"},"object":{"id":"23819462-9bdf-5856-beac-68b3dca9cf85","slug":"thymulin","display_name":"Thymulin","entity_type_key":"peptide"},"evidence_count":1,"mechanism_event":{"id":"71ea34cb-2168-58e8-b4c7-77954e34944a","stable_key":"18100170-a014-51c3-adeb-9dab4162b8cc:complex-structure-event","event_type":"experimental_observation","label":"NMR in DMSO-d6 identified 1:1 and 1:2 zinc-peptide complexes; Ser4 and the Asn9 terminal carboxylate coordinated zinc, with Ser8 participating in the 1:1 complex.","description":"The structural qualification matters: the 1988 NMR work was performed in **DMSO-d₆**, not blood. It identified 1:1 and 1:2 zinc–peptide complexes depending on the mixture. Coordination involved Ser4 and the Asn9 **terminal carboxylate**, with Ser8 also participating in the 1:1 complex. This supports a metal-dependent conformation but does not establish the distribution of complexes in living tissues. “One zinc per active peptide” should therefore describe a conventional preparation/activation model, not proven universal physiological occupancy. [NMR study](https://pubmed.ncbi.nlm.nih.gov/3356698/)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9bac7a31-4b5b-59f2-8dad-39269ddbb8b1","slug":"fts-peptide","display_name":"Zinc-free FTS nonapeptide component","entity_type_key":"peptide"},"role":"tested factor","stoichiometry":null,"state_label":"as reported","sequence_order":0,"notes":""},{"entity":{"id":"23819462-9bdf-5856-beac-68b3dca9cf85","slug":"thymulin","display_name":"Thymulin","entity_type_key":"peptide"},"role":"measured outcome","stoichiometry":null,"state_label":"not_reported","sequence_order":1,"notes":""},{"entity":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"role":"coordinated metal","stoichiometry":null,"state_label":"","sequence_order":2,"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 complexes in DMSO-d6; not serum or intracellular occupancy.","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":"NMR in DMSO-d6 identified 1:1 and 1:2 zinc-peptide complexes; Ser4 and the Asn9 terminal carboxylate coordinated zinc, with Ser8 participating in the 1:1 complex.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"NMR study of a lymphocyte differentiating thymic factor. An investigation of the Zn(II)-nonapeptide complexes (thymulin). | 1988 | DOI 10.1016/s0021-9258(18)60603-9 | PMID 3356698 | https://pubmed.ncbi.nlm.nih.gov/3356698/","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference lines 27-27; exact primary location described in quoted passage where extracted.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"74b227bc-c52a-5026-85c7-1b60aaff7b8e","evidence_kind":"source_excerpt","locator":"Lines 27-27","start_line":27,"end_line":27,"excerpt":"The structural qualification matters: the 1988 NMR work was performed in **DMSO-d₆**, not blood. It identified 1:1 and 1:2 zinc–peptide complexes depending on the mixture. Coordination involved Ser4 and the Asn9 **terminal carboxylate**, with Ser8 also participating in the 1:1 complex. This supports a metal-dependent conformation but does not establish the distribution of complexes in living tissues. “One zinc per active peptide” should therefore describe a conventional preparation/activation model, not proven universal physiological occupancy. [NMR study](https://pubmed.ncbi.nlm.nih.gov/3356698/)","model_system":"Purified complexes in DMSO-d6; not serum or intracellular occupancy.","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}