GLO1 (At3g14420; UniProt Q9LRR9) - curation notes

Deep research could not be run for this gene (no deep-research provider API keys in this
environment). These notes were built only from cached publications (publications/PMID_*.md),
the UniProt record (GLO1-uniprot.txt) and papers cached with ai-gene-review fetch-pmid.
No -deep-research-*.md file exists for this gene.

Nomenclature warning (GOX1 vs GOX2)

• UniProt: GN Name=GLO1; OrderedLocusNames=At3g14420, with Short=GOX1 (from PMID:25416784)
  and DR TAIR; AT3G14420; GOX1. So in this folder GLO1 = GOX1 = At3g14420.
• The two leaf genes are adjacent on chromosome 3 (At3g14415 and At3g14420) and the
  GOX1/GOX2 names are crossed in part of the literature:
• Dellero et al. 2015 uses TAIR naming: PMID:25416784.
• Reumann et al. 2007 (leaf peroxisome proteome) uses the crossed naming:
  PMID:17951448. Here "GOX2" = our GLO1.
• UniProt Q9LRS0 (GLO2, At3g14415) lists Synonyms=GOX1, reflecting the crossed usage.
• Kerchev et al. 2016 (PMID:27225899) uses TAIR naming in its full text (GOX1 = At3g14420,
  GOX2 = At3g14415; checked on the PMC full text via WebFetch, not in the cached abstract).
• Always check the AGI locus, not the GOX number.

Molecular function

• Glycolate oxidase (EC 1.1.3.15), an FMN-dependent (S)-2-hydroxy-acid oxidase:
  [file:ARATH/GLO1/GLO1-uniprot.txt "Catalyzes the oxidation of glycolate to glyoxylate, with a
  reduction of O2 to H2O2"]; kinetics from recombinant enzyme: Km 0.22 mM glycolate, kcat
  29.86 s-1 (UniProt, from PMID:25416784).
• Recombinant His-tagged AtGOX1 and AtGOX2 were purified and assayed with glycolate
  PMID:25416784; the study supports a hydride
  transfer mechanism PMID:25416784.
• GO term: GO:0008891 glycolate oxidase activity is obsolete and replaced by GO:0003973
  (S)-2-hydroxy-acid oxidase activity (verified in OLS4, term_replaced_by: GO_0003973).
• Family: FMN-dependent alpha-hydroxy acid dehydrogenase family (PROSITE PS51349, Pfam
  PF01070, PANTHER PTHR10578:SF107); FMN binding residues by similarity to spinach GOX P05414.
• Class description PMID:22303256.
• No experimental data found for GLO1 activity on L-lactate (that data, PMID:21828292, is for
  GOX2/At3g14415 only).

Localization

• Peroxisome (UniProt by similarity); C-terminal PTS1 tripeptide ARL> per Reumann 2007, and the
  protein was detected in purified leaf peroxisomes PMID:17951448.
• Detections in chloroplast, stroma, nucleus, plasmodesma, apoplast, cytosolic ribosome and
  cytosol proteomes are most likely carry-over of this very abundant leaf peroxisomal protein;
  the Arabidopsis cytosolic proteome (PMID:21166475) gave a NOT cytosol (RCA) annotation.

Biological process

• Photorespiration (C2 cycle), glycolate -> glyoxylate step in the leaf peroxisome.
  PMID:22303256, and redundancy explained the lack of mutants in
  classical screens PMID:22303256.
• GOX1 and GOX2 are redundant for photorespiration under normal conditions:
  PMID:26896850; double
  knock-down PMID:26896850.
• GOX1 is the more important isoform under high photorespiratory flux and in the cat2 background:
  PMID:27225899 and PMID:27225899
• Post-translational regulation: GOX1 S-nitrosylation at Cys-343 in cat2 PMID:39777728
  (abstract only; locus mapping for "GOX1" not verified from the cached abstract).
• Ozone/photo-oxidative stress: a T-DNA line at the GOX1/GOX2 locus with ~60% GOX activity is
  ozone sensitive PMID:28339978.
• Defence / H2O2 production: GOX-derived H2O2 contributes to nonhost resistance
  PMID:22286136. Cached text is abstract-only; Kerchev 2016 full text
  states that gox1-1 and gox2-1 were described in Rojas et al. 2012, consistent with the GOA IMP
  rows on both genes. This is a secondary, non-core role of the H2O2 product.

RNA binding

• Leaf RNA interactome capture lists "(S)-2-HYDROXY-ACID OXIDASE" among moonlighting enzymes
  PMID:32344669; no functional follow-up.

Module comparison (modules/photorespiration_c2_cycle.yaml)

• Module: GO:0003973 MF, GO:0009853 photorespiration, GO:0005777 peroxisome. Review agrees on MF
  and location; for process the existing annotation is the more specific GO:0009854 oxidative
  photosynthetic carbon pathway (part_of GO:0009853), which is accepted here.