Secreted neutral ceramidase (EC 3.5.1.23). Purified from culture supernatant and
shown to hydrolyse ceramides reversibly PMID:9603946. Gene cloned and expressed in E. coli PMID:10593963. In the lung it is part of the SphR regulon; a clean PA0845 deletion abolishes ceramide-induced sphA PMID:24465209; renamed cerN PMID:24465209.
Other seeds' experimental support from .cache/paint/IBD.gaf and QuickGO, 2026-11-05.
| PTN node | node term | n_seeds | leaf IBAs | seed annotation (term, evidence, PMID) | verdict | rationale | other seeds | IBD stands without this seed? |
|---|---|---|---|---|---|---|---|---|
| PTN004377481 | GO:0017040 N-acylsphingosine amidohydrolase activity | 7 | 156 (78 taxa) | GO:0017040, IMP PMID:10593963 (PseudoCAP), IDA PMID:9603946 (UniProt) | SOUND | PA0845 purified and assayed; recombinant expression confirms activity. Self-seed expected. | human ASAH2 Q9NR71, mouse/rat/zebrafish/fly ceramidases, M. tuberculosis O06769 (IDA PMID:10593963/20139604) | Yes |
Node term is the exact ceramidase activity; suits the clade. No PSEUDOCAP or GO_CENTRAL
defect on the GO:0017040 seed.
Related nodes on the same PTN (leaf IBAs received by PA0845, and where PA0845 seeds):
- GO:0042759 long-chain fatty acid biosynthetic process: seeded by PA0845 (Q9I596) and
O06769 only. A ceramidase RELEASES a free fatty acid by hydrolysis; it does not
synthesise one. Node term misfits the family -> GO_CENTRAL defect (CHECK, PROBABLE),
recorded on the PA0845 IDA row (most direct evidence). Rows MARK_AS_OVER_ANNOTATED.
- GO:0046512 sphingosine biosynthetic process: KEEP_AS_NON_CORE (sphingosine is a true
product; conserved family annotation, peripheral role here).
- GO:0046514 ceramide catabolic process: ACCEPT (the reaction performed).
- GO:0051872 sphingosine catabolic process IDA PMID:24465209 (PseudoCAP, full text read):
cerN generates sphingosine and is upstream of the sph catabolic genes; it does not
catabolise sphingosine. MODIFY to GO:0046514; PSEUDOCAP WRONG_TERM, CONFIRMED.