The brown ommochrome eye pigment xanthommatin is made from tryptophan through the kynurenine pathway, which in insects is also the main route of tryptophan catabolism. Tryptophan 2,3-dioxygenase (vermilion) opens the indole ring to give N-formylkynurenine, kynurenine formamidase (Kfase) releases kynurenine, and kynurenine 3-monooxygenase (cinnabar) hydroxylates it to 3-hydroxykynurenine. 3-Hydroxykynurenine is imported into pigment granules of the eye and other tissues by the White-Scarlet ABC transporter, where it is condensed to xanthommatin; this last step requires the heme peroxidase Cardinal. Mutations in v, cn, w, st and cd give the classic eye-colour phenotypes that lack or reduce brown pigment.
Boundary. The module joins the FlyBase tryptophan catabolism and ommochrome pigment groups, which share v, Kfase and cn. White also pairs with Brown to import pteridine (drosopterin) precursors; that heterodimer belongs to pteridine pigment synthesis and is not modelled here. No molecular function is given to the White-Scarlet transporter, since the exact transported substrate has been inferred from genetics rather than transport assays, or to Cardinal, which has peroxidase activity by homology but whose precise chemistry in xanthommatin synthesis is not settled. Kynurenic acid and other kynurenine side branches are not part of this module. FlyBase groups realized by this module: TRYCAT (FBgg0002189), OMMOBI (FBgg0002233). Participants were generated from the FlyBase gene-group membership and mapped to UniProtKB by projects/FLYBASE_GENE_GROUPS/generate_modules.py from module_specs/dmel_ommochrome_biosynthesis.yaml. None of the member genes has a gene review in this repository yet.
All recommended fields populated.
✗ none found
No MODULE:dmel_ommochrome_biosynthesis deep-research report alongside the module YAML.
✓ every leaf node grounds to a representative protein.
✓ every declared conforms_to bundle matches its template motif.
✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.
0 gene-function check(s) reflected in core functions · 0 conflict(s) · 3 evidence or coverage gap(s) (3 comparison(s))
Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.
| Annoton | Participant | Function | Assessment |
|---|---|---|---|
| tryptophan_dioxygenation_v | v UniProtKB:P20351 Gene |
L-tryptophan 2,3-dioxygenase activity GO:0004833 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| formylkynurenine_hydrolysis_kfase | Kfase UniProtKB:Q9VMC9 Gene |
arylformamidase activity GO:0004061 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| kynurenine_hydroxylation_cn | cn UniProtKB:A1Z746 Gene |
kynurenine 3-monooxygenase activity GO:0004502 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
0 complete review(s) · 0 with deep research · 6 missing review · 0 reviewed but lacking deep research
| Gene | Review | Complete | Deep research |
|---|---|---|---|
| cn A1Z746 | ✗ | — | — |
| w P10090 | ✗ | — | — |
| v P20351 | ✗ | — | — |
| st P45843 | ✗ | — | — |
| cd Q9VCW2 | ✗ | — | — |
| Kfase Q9VMC9 | ✗ | — | — |
Kynurenine pathway that converts tryptophan to 3-hydroxykynurenine and, in pigment granules, to the ommochrome xanthommatin.