Cao1 is a copper-dependent, quinone-containing primary amine oxidase that catalyzes oxidative deamination of primary amines. The enzyme supports utilization of ethylamine as a nitrogen source in heterologous yeast assays and obtains copper in part through the Atx1 metallochaperone. Cao1 is cytosolic in vegetative cells and concentrates within forespores during meiosis, where its activity depends on copper supplied through Mfc1.
The 2006 primary study expresses pombe spao1/cao1 in budding yeast and establishes active primary-amine oxidation and ethylamine-dependent growth. The 2008 full text directly assays native pombe Cao1, copper loading and activity-retaining Cao1-GFP. Its statements about cao1-deletion ethylamine growth are labeled unpublished observations within that paper; they are not treated as a separately displayed quantitative experiment.
The 2011 Mfc1 paper directly images Cao1-GFP within forespores in figure6C and measures its activity. The focus on Mfc1 does not make the Cao1 annotation a misattribution. Falcon underestimates this direct localization evidence. GO:0008131 was checked against QuickGO; its RHEA reaction and synonyms encompass primary-amine oxidation, despite the potentially confusing current label “primary methylamine oxidase activity.”
Copper is experimentally required. TPQ is supported by conserved cofactor chemistry and the curated ortholog-attributed record; target-specific TPQ spectroscopy is not claimed. The Cu-loading phenotype is retained as non-core homeostasis, and TAS detoxification remains unresolved because the cited germination paper is abstract-only in the cache.
Exact retained output. These are name/location claims, not emitted GO/EC predictions. CNN denotes overlap with existing supported annotation; it does not establish literal membership in the training set.
| Claim type | Verbatim output | Assessment | Evidence and interpretation |
|---|---|---|---|
| name | Amine oxidase | LSP | The broad reaction class is correct; target assays establish a copper-dependent primary-amine oxidase with ethylamine catabolism, and the sequence belongs to the copper/TPQ oxidase family (PMID:16946276; PMID:18723604). |
PMID:18723604(https://pubmed.ncbi.nlm.nih.gov/18723604/):
the Atx1 metallochaperone represents an important source of copper for Cao1.
PMID:16946276(https://pubmed.ncbi.nlm.nih.gov/16946276/):
Expression of
spao1(+) resulted in the production of an active enzyme capable of catalysing
the oxidative deamination of primary amines.
PMID:18723604(https://pubmed.ncbi.nlm.nih.gov/18723604/):
Cao1-GFP was localized
in the cytosol
PMID:21828039(https://pubmed.ncbi.nlm.nih.gov/21828039/):
Cao1-GFP displayed fluorescent staining that was mainly observed within the forespores
The genuine Falcon report is retained with its provider metadata and artifact. Its conclusions were checked against the target record, exact accession and primary sources described above. Scientific uncertainties are recorded as UNC/UNDECIDED findings rather than a request for another reviewer to perform this assessment.
Identity: Q9P7F2 is the canonical, Swiss-Prot reviewed 712-aa product of cao1 (SPAC2E1P3.04); not a
fragment, isoform or alternative gene model. All catalytic features are present (TPQ precursor Tyr407,
catalytic Asp321, Cu-ligand His456/458/460/621/627 region, disulfide 340-366).
Evolutionary placement: PANTHER PTHR10638 (copper amine oxidase), subfamily SF86 "COPPER AMINE OXIDASE
1-RELATED". SF86 also contains Hansenula polymorpha (Pichia angusta) AMO/HPAO P12807, Arthrobacter
phenylethylamine oxidase P46881, histamine oxidase Q59118, Arthrobacter maoI/maoII, and the pombe paralog
cao2 (O42890). PAINT IBDs for GO:0008131, GO:0005507 and GO:0009308 sit at the family root PTN000067313,
so Cao1 legitimately inherits them; Cao1's own PomBase IDA is among the node's descendant evidence. The
full text of PMID:18723604 states that Cao1 is 57% identical to HPAO, its closest characterised relative
PMID:18723604. The PANTHER family review
(interpro/panther/PTHR10638/PTHR10638-review.yaml) also places Cao1 in SF86; no disagreement.
Changes vs previous version:
- GO:0006878 intracellular copper ion homeostasis (IMP): KEEP_AS_NON_CORE -> MARK_AS_OVER_ANNOTATED. Full
text shows the cao1 deletion only loses amine oxidase activity; Cao1 is the copper client whose activity
is used as a bioavailability readout, a necessity relationship, not participation in homeostasis.
- GO:0048038 quinone binding (IEA): ACCEPT -> KEEP_AS_NON_CORE. TPQ is a covalently modified residue of
Cao1, not an exogenous bound quinone; consistent with rat Aoc1 handling.
- Strengthened supporting quotes (His mutagenesis, cao1-deletion loss of activity, Cao1-GFP cytosol, meiotic
activity in PMID:21828039), added reference_review entries, propagation_review for the MODIFY IBA,
questions and experiments; description rewritten to include substrate range and the inactive paralog Cao2.
- GO:1990748 cellular detoxification (TAS, PMID:28572514) stays UNDECIDED: full text not retrievable
(Europe PMC / PMC BioC returned no body); abstract does not mention Cao1.
No NEW terms proposed. Nitrogen-source use of ethylamine in S. pombe itself is only "unpublished" in
PMID:18723604, so no nitrogen-utilization process term is added beyond amine catabolic process.
Relative to review next: Hansenula polymorpha AMO (P12807, AMO_PICAN), same PANTHER subfamily SF86, the
best-characterised fungal copper amine oxidase (structure, TPQ biogenesis). No review exists in the repo.
No modules in modules/ include cao1.