{"id":"dc0f8d24-09d9-57f6-ac79-cbddf307875e","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-sdsl-distinction","predicate":"has_lower_activity_than","statement":"Human serine dehydratase-like protein had lower activity than the hepatic enzyme; structures and complementary mutations implicated active-site differences, including Gly72.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e80ff884-a792-5461-be30-983521979299","mechanism_event_label":"Related enzymes are not interchangeable just because they use the same substrate.","subject":{"id":"694036f6-b7f5-5bc0-8967-a4de835ba23c","slug":"sdsl","display_name":"Human serine dehydratase-like protein / SDSL","entity_type_key":"protein"},"object":{"id":"fc4df87c-aec1-5de5-8122-effc2c5ee721","slug":"sds","display_name":"Human hepatic serine dehydratase / SDS","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"e80ff884-a792-5461-be30-983521979299","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-sdsl-distinction-event","event_type":"observed_relationship","label":"Related enzymes are not interchangeable just because they use the same substrate.","description":"Human serine dehydratase-like protein had lower activity than the hepatic enzyme; structures and complementary mutations implicated active-site differences, including Gly72.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"694036f6-b7f5-5bc0-8967-a4de835ba23c","slug":"sdsl","display_name":"Human serine dehydratase-like protein / SDSL","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"fc4df87c-aec1-5de5-8122-effc2c5ee721","slug":"sds","display_name":"Human hepatic serine dehydratase / SDS","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c882cd0b-9d83-5b07-bd1c-fe4d45657dcb","slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human enzymes, 2.8-angstrom SDSL structure and site-directed mutagenesis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is a comparison of enzyme constructs, not clinical evidence of a dietary shortage.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Related enzymes are not interchangeable just because they use the same substrate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"A catalytic mechanism that explains a low catalytic activity of serine dehydratase like-1 from human cancer cells: crystal structure and site-directed mutagenesis studies. · 2008 · https://pubmed.ncbi.nlm.nih.gov/18342636/ · DOI 10.1016/j.bbagen.2008.01.020","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"eaa135f4-133f-5c19-8eaa-5d2827b52886","evidence_kind":"source_excerpt","locator":"Lines 374-380","start_line":374,"end_line":380,"excerpt":"## l-serine-sdsl-distinction\nRelated enzymes are not interchangeable just because they use the same substrate.\nHuman serine dehydratase-like protein had lower activity than the hepatic enzyme; structures and complementary mutations implicated active-site differences, including Gly72.\nModel: Recombinant human enzymes, 2.8-angstrom SDSL structure and site-directed mutagenesis.\nLimitations: This is a comparison of enzyme constructs, not clinical evidence of a dietary shortage.\nEvidence access: Primary abstract\nA catalytic mechanism that explains a low catalytic activity of serine dehydratase like-1 from human cancer cells: crystal structure and site-directed mutagenesis studies. · 2008 · https://pubmed.ncbi.nlm.nih.gov/18342636/ · DOI 10.1016/j.bbagen.2008.01.020","model_system":"Recombinant human enzymes, 2.8-angstrom SDSL structure and site-directed mutagenesis.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"70bcf57a-36bb-563f-9073-2d616e5f155a","stable_key":"import-649e861b-265a-5912-bc36-3a73e53ef892","title":"L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"22a750ce2b94f8607268c58322c48c4f0468f403b72a4008307538a6e5ff86d5","revision_id":"c1d6a7e1-9558-5bc6-9e3b-7080c26d3dbc","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}