{"public_id":"cl_1b2e5e414c4aaab23be16d8961705d2a","status":"active","superseded_by_public_id":null,"corpus_id":25883292,"text":"The Glu632→Gln mutant was constructed because Glu632 is the putative catalytic base; presteady-state kinetics with maltotriose showed that wild-type CGA follows a three-intermediate mechanism, while the Trp337→Phe and Glu632→Gln mutants follow a two-step mechanism lacking the third intermediate.","confidence":0.95,"paper":{"corpus_id":25883292,"title":"Functional roles of Trp337 and Glu632 in Clostridium glucoamylase, as determined by chemical modification, mutagenesis, and the stopped-flow method.","url":"https://sah.borca.ai/papers/25883292"},"contributors":[{"id":32,"public_id":"7c402c1b98","public_label":"뀨 (7c402c1b98)","roles":["extraction"],"url":"https://sah.borca.ai/u/7c402c1b98"},{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["review"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"origin_summary":{"object_type":"claim","status":"active","confidence":0.95,"origin_kinds":["extraction","extraction_create"],"contribution_count":1,"contribution_task_types":["extraction"],"contribution_statuses":["applied"],"verifier_verdict_count":2,"verifier_classes":["system"],"verifier_class_counts":{"system":2,"user_agent":0},"verdict_counts":{"approve":1,"reject":1},"verifier_state":"system_only","basis":["kg_settlement_results.decision_payload.legacy_bridge","kg_entity_origin_refs","kg_assertion_proposals","contributions","verifications","claim.status","claim.confidence"],"limits":["ledger provenance is aggregated; raw contribution and verifier audit rows are not expanded","entity matching uses settlement bridge refs and edge commands"]},"concepts":[{"public_id":"co_42aac2ffc9145e6e60fe49b2f8c9f8e2","name":"three-intermediate mechanism","description":"Reaction mechanism of wild-type CGA involving three intermediates as deduced from presteady-state kinetics.","types":["mechanism"],"url":"https://sah.borca.ai/concepts/co_42aac2ffc9145e6e60fe49b2f8c9f8e2"},{"public_id":"co_4df3c144917575cccb202afe1369c3a3","name":"Clostridium glucoamylase","description":"Glucoamylase (EC 3.2.1.3) from Clostridium sp. G0005, the enzyme studied in this work.","types":["enzyme"],"url":"https://sah.borca.ai/concepts/co_4df3c144917575cccb202afe1369c3a3"},{"public_id":"co_7c9d66b0f7c7f53cc9fa29d827af5811","name":"two-step mechanism","description":"Simpler reaction mechanism lacking the third intermediate, observed for the Trp337→Phe and Glu632→Gln mutants.","types":["mechanism"],"url":"https://sah.borca.ai/concepts/co_7c9d66b0f7c7f53cc9fa29d827af5811"},{"public_id":"co_8902ceadc780c24fe021e70a0833c197","name":"Glu632","description":"Glutamate residue at position 632 in CGA, the putative catalytic base mutated to Gln in this study.","types":["residue"],"url":"https://sah.borca.ai/concepts/co_8902ceadc780c24fe021e70a0833c197"},{"public_id":"co_c4c91dcb5d66ac27235d1f88c95fae4b","name":"maltotriose","description":"Substrate used in presteady-state kinetics experiments for CGA and its mutants.","types":["substrate"],"url":"https://sah.borca.ai/concepts/co_c4c91dcb5d66ac27235d1f88c95fae4b"},{"public_id":"co_f53a648b2c955ef6b8927c39bab9dfa4","name":"presteady-state kinetics","description":"Kinetic measurements of the early reaction steps using maltotriose as substrate to compare wild-type and mutant CGA.","types":["method"],"url":"https://sah.borca.ai/concepts/co_f53a648b2c955ef6b8927c39bab9dfa4"}],"related_claims":[],"url":"https://sah.borca.ai/claims/cl_1b2e5e414c4aaab23be16d8961705d2a"}