id: P49264 gene_symbol: CYP71B1 product_type: PROTEIN status: COMPLETE taxon: id: NCBITaxon:13288 label: Thlaspi arvense description: Cytochrome P450 71B1 is a heme-thiolate cytochrome P450 monooxygenase of field pennycress, a member of the CYP71 clan that dominates plant specialized (defense) metabolism. It was identified as a full-length cDNA cloned from Thlaspi arvense in 1994, but its substrate, catalyzed reaction, metabolic pathway, expression pattern, and subcellular localization have not been experimentally determined. Based on conserved P450 architecture it is predicted to catalyze NADPH- and O2-dependent oxidation of an organic substrate using a heme cofactor, with the heme iron coordinated by a conserved axial cysteine; like most plant P450s it is expected, but not shown, to be anchored to the endoplasmic reticulum membrane. alternative_records: - id: A0AAU9RUE5 relationship: REFERENCE_PROTEOME_EQUIVALENT reference_proteome: UP000836841 reviewed_on: '2026-10-19' reason: Retain P49264 as the primary Swiss-Prot accession. The reference sequence is exactly identical across all 496 residues. Other P450 hits are substantially less similar. This supports equivalent protein representation without relying on the broad automatic cytochrome-P450 name to establish substrate specificity. evidence: - type: PROTEOME_SEARCH description: MMseqs2 searched 26,379 sequences across UP000836841 at E <= 1e-5 and sensitivity 7.5, returning 214 hits. Every returned sequence was globally aligned using BLOSUM62 with gap-open -10 and extension -0.5. Scores and sequences for all 214 returned candidates are retained, with 10 detailed alignment files. The heuristic search does not establish genomic absence or unique locus identity. supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: 'target_sequence_count: 26379' - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: 'candidate_count: 214' - type: SEQUENCE_COMPARISON description: 'A0AAU9RUE5: 496 identities across 496 global-alignment columns (100.0% identity including gaps), 0 substitutions and 0 gap columns. Query coverage is 100.0%; target coverage is 100.0%. Sequence similarity is interpreted in the manual rationale. Identity over paired residues is 100.0000% (496/496); gap columns are excluded from this denominator.' supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: |- query_length: 496 target_length: 496 alignment_columns: 496 identities: 496 mismatches: 0 gap_columns: 0 identity_percent: 100.0 query_coverage_percent: 100.0 target_coverage_percent: 100.0 - type: PROTEOME_MEMBERSHIP description: The primary accession is outside every searched exact-taxon reference proteome. Current UniProt records place A0AAU9RUE5 in UP000836841 and give it the same taxon as the primary. supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: 'primary_in_any_reference_proteome: false' - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: 'alternative_in_reference_proteome: true' - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: 'same_taxon: true' - type: RECORD_HISTORY description: 'Sampled UniSave observations: 26-NOV-2014, entry version 68.: no Proteomes cross-reference; 07-OCT-2020, entry version 77.: no Proteomes cross-reference; 27-NOV-2024, entry version 86.: no Proteomes cross-reference. These dated observations do not establish uninterrupted membership/absence, the exact change date, or UniProt''s motivation.' supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: |- entry_date: 26-NOV-2014, entry version 68. proteomes: [] - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: |- entry_date: 07-OCT-2020, entry version 77. proteomes: [] - reference_id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml supporting_text: |- entry_date: 27-NOV-2024, entry version 86. proteomes: [] existing_annotations: - term: id: GO:0004497 label: monooxygenase activity evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: Well-supported family-level inference. The protein has canonical cytochrome P450 domain architecture (Pfam PF00067), and plant P450s are heme-thiolate monooxygenases. The specific substrate and reaction are unknown, but monooxygenase activity is a sound conservative annotation. action: ACCEPT supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md supporting_text: Plant cytochrome P450s are heme-thiolate monooxygenases that catalyze oxygenation reactions - term: id: GO:0005506 label: iron ion binding evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: Correct. The P450 catalytic center binds an iron-containing heme; UniProt annotates an axial heme iron-binding residue at position 436. Iron ion binding is appropriate, captured more specifically by the heme binding annotation. action: ACCEPT supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md supporting_text: a conserved cysteine coordinates the heme iron in the P450 catalytic center - term: id: GO:0016705 label: oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: Correct and standard for a cytochrome P450 monooxygenase, which uses molecular oxygen with NADPH as the paired electron donor. Conservative family-level inference. action: ACCEPT supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md supporting_text: RH + O2 + NADPH + H+ -> ROH + H2O + NADP+ - term: id: GO:0020037 label: heme binding evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables review: summary: Correct. Cytochrome P450s are heme-thiolate proteins; UniProt annotates the axial heme iron-binding residue (position 436). This is the most specific cofactor annotation and underpins the monooxygenase activity. action: ACCEPT supported_by: - reference_id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md supporting_text: P450s share a conserved catalytic center in which a conserved cysteine coordinates the heme iron core_functions: - description: CYP71B1 is a heme-thiolate cytochrome P450 monooxygenase predicted to catalyze NADPH/O2-dependent oxidation of an organic substrate. The physiological substrate, reaction, and pathway are unknown; CYP71-clan membership suggests a role in specialized (defense) metabolism, but this is not established for the pennycress protein. molecular_function: id: GO:0004497 label: monooxygenase activity supported_by: - reference_id: PMID:8066138 supporting_text: Cloning and sequencing of a full-length cDNA from Thlaspi arvense L. that encodes a cytochrome P-450 - reference_id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md supporting_text: heme-thiolate monooxygenase; CYP71 clan enriched in plant specialized metabolism; substrate of pennycress CYP71B1 not determined references: - id: file:THLAR/CYP71B1/CYP71B1-record-evidence.yaml title: Compact archived record and sequence evidence for P49264 - id: GO_REF:0000002 title: Gene Ontology annotation through association of InterPro records with GO terms findings: [] - id: PMID:8066138 title: Cloning and sequencing of a full-length cDNA from Thlaspi arvense L. that encodes a cytochrome P-450. findings: - statement: Reports the full-length cDNA of Thlaspi arvense CYP71B1 (a cytochrome P450); a sequence report with no functional characterization. reference_section_type: ABSTRACT reference_review: relevance: MEDIUM correctness: VERIFIED review_notes: PubMed-verified. The sole primary reference for this gene; it establishes existence/sequence only, not function. Abstract-only in cache. - id: file:THLAR/CYP71B1/CYP71B1-deep-research-falcon.md title: Falcon/Edison deep research report for CYP71B1, Thlaspi arvense findings: - statement: Concludes pennycress CYP71B1 is functionally uncharacterized; only a heme-thiolate plant P450 monooxygenase classification can be inferred, with CYP71-clan members commonly acting in specialized/defense metabolism (e.g. Arabidopsis camalexin pathway). Flags symbol ambiguity with Arabidopsis CYP71B1 (At1g13080). reference_section_type: OTHER suggested_questions: - question: What substrate(s) and reaction does Thlaspi arvense CYP71B1 catalyze, and in which pathway (e.g. glucosinolate, indole/camalexin-type, or other specialized metabolism) does it act? - question: Is CYP71B1 anchored to the endoplasmic reticulum membrane, as is typical for CYP71-clan plant P450s? suggested_experiments: - description: Heterologously express CYP71B1 (e.g. in yeast or N. benthamiana microsomes with a plant cytochrome P450 reductase) and screen candidate substrates from Brassicaceae specialized metabolism (indole/tryptophan-derived intermediates, glucosinolate precursors) by LC-MS to identify the catalyzed reaction. - description: Determine subcellular localization with a fluorescent-protein fusion and test for an N-terminal ER membrane anchor.