{"id":"0362bd6d-a185-5d70-b300-4b4e0515e173","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-pam-lyase-spared","predicate":"does-not-inactivate-assayed-lyase-of","statement":"Under conditions that inactivated hydroxylase-dependent rat PAM amidation, ascorbate did not impair conversion of the pre-hydroxylated dansyl-Tyr-Val-alpha-hydroxyglycine intermediate to its amide.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"18108ef0-f170-51f9-9555-3299904d0232","mechanism_event_label":"Bypassing the damaged hydroxylation step showed that the finishing lyase step still worked.","subject":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"object":{"id":"cb1d701b-c3cb-5f8e-9bbe-c796d6028a0e","slug":"rat-pam-type-a-75kda","display_name":"Recombinant rat type-A 75-kDa peptidylglycine amidating enzyme","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"18108ef0-f170-51f9-9555-3299904d0232","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-pam-lyase-spared-event","event_type":"biochemical_relationship","label":"Bypassing the damaged hydroxylation step showed that the finishing lyase step still worked.","description":"Under conditions that inactivated hydroxylase-dependent rat PAM amidation, ascorbate did not impair conversion of the pre-hydroxylated dansyl-Tyr-Val-alpha-hydroxyglycine intermediate to its amide.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"role":"assay-exposure","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"cb1d701b-c3cb-5f8e-9bbe-c796d6028a0e","slug":"rat-pam-type-a-75kda","display_name":"Recombinant rat type-A 75-kDa peptidylglycine amidating enzyme","entity_type_key":"protein_state"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"af26b168-785d-54c9-a0ca-7448fb84bcdf","slug":"dansyl-tyr-val-hydroxyglycine","display_name":"Dansyl-Tyr-Val-alpha-hydroxyglycine","entity_type_key":"small_molecule"},"role":"substrate-bypassing-PHM","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"62a1bc7d-0223-5579-8771-bceb91d3a9c3","slug":"dansyl-tyr-val-amide","display_name":"Dansyl-Tyr-Val-NH2","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant rat type-A 75-kDa PAM, purified enzyme assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Time/concentration series of ascorbate, DHA or H2O2; fluorescent peptide substrate or pre-hydroxylated intermediate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Distinct-substrate assay localizes the defect; no claim that all PAM domains share the same redox/cofactor dependence.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin C research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Rattus norvegicus (protein)","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Bypassing the damaged hydroxylation step showed that the finishing lyase step still worked.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[pam1992] Selective inactivation of the hydroxylase activity of bifunctional rat peptidylglycine alpha-amidating enzyme. (1992). https://pubmed.ncbi.nlm.nih.gov/1567215/ DOI: 10.1016/0003-9861(92)90730-k","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-free recombinant rat protein","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"03f6cc42-75f0-5dc4-b462-6042a6e5d661","evidence_kind":"source_excerpt","locator":"Lines 924-935","start_line":924,"end_line":935,"excerpt":"### vc-enzyme-pam-lyase-spared\nUnder conditions that inactivated hydroxylase-dependent rat PAM amidation, ascorbate did not impair conversion of the pre-hydroxylated dansyl-Tyr-Val-alpha-hydroxyglycine intermediate to its amide.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Bypassing the damaged hydroxylation step showed that the finishing lyase step still worked.\norganism: Rattus norvegicus (protein)\ntissue_or_cell_type: Cell-free recombinant rat protein\nexperimental_model: Recombinant rat type-A 75-kDa PAM, purified enzyme assays\nlimitations: Distinct-substrate assay localizes the defect; no claim that all PAM domains share the same redox/cofactor dependence.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: Time/concentration series of ascorbate, DHA or H2O2; fluorescent peptide substrate or pre-hydroxylated intermediate.\n[pam1992] Selective inactivation of the hydroxylase activity of bifunctional rat peptidylglycine alpha-amidating enzyme. (1992). https://pubmed.ncbi.nlm.nih.gov/1567215/ DOI: 10.1016/0003-9861(92)90730-k","model_system":"Recombinant rat type-A 75-kDa PAM, purified enzyme assays","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [pam1992] Selective inactivation of the hydroxylase activity of bifunctional rat peptidylglycine alpha-amidating enzyme. (1992). https://pubmed.ncbi.nlm.nih.gov/1567215/ DOI: 10.1016/0003-9861(92)90730-k","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"fa811221-13bd-5c10-adc1-eaf097c7703c","stable_key":"import-cb568d28-484a-5c2e-9fcc-2d780358e514","title":"Vitamin C: 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. 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