Gcat (CG10361, Q9VTN9) notes

2026-10-09 review session

• Deep research (falcon, with perplexity-lite fallback) timed out / failed; no deep-research file.
  Review is based on the UniProt record and GOA rows.
• No Drosophila-specific publication is attached to any Gcat GOA row; all annotations are
  IBA/ISS/IEA from the bovine GCAT ortholog (Q0P5L8) and InterPro IPR011282.
• UniProt: "2-amino-3-ketobutyrate coenzyme A ligase, mitochondrial", EC 2.3.1.29,
  "Reaction=glycine + acetyl-CoA = (2S)-2-amino-3-oxobutanoate + CoA" with
  "PhysiologicalDirection=right-to-left", i.e. glycine-forming
  [file:DROME/Gcat/Gcat-uniprot.txt "PhysiologicalDirection=right-to-left"].
• PANTHER PTHR13693:SF102 (mitochondrial GCAT subfamily); PLP cofactor.
• Pathway partner: Tdh (CG5955) makes 2-amino-3-oxobutanoate from threonine
  PMID:31313987.

Decisions

• All annotations accepted except generic transferase activity (MODIFY -> GO:0008890).
• Core function: glycine C-acetyltransferase activity in mitochondrion, L-threonine catabolism and
  glycine biosynthesis.

Update: deep research arrived

• The first falcon run finished after the wrapper timed out and wrote Gcat-deep-research-falcon.md.
• It confirms there is no enzyme assay of fly Gcat; identity rests on orthology
  [Gcat-deep-research-falcon.md "The publication establishes an orthology-based annotation, not an enzyme assay of Q9VTN9."].
• A 2026 fly study (Yoshinari et al., per the deep research) reports Gcat expression mainly in fat body,
  induced by starvation, and fat-body Tdh knockdown reduces threonine-derived label in glycine and serine
  [Gcat-deep-research-falcon.md "fat-body Tdh knockdown reduced incorporation of threonine-derived isotope into glycine and serine"].
  This supports the pathway context; no change to review decisions.