| Claim | Species/gene | Evidence type | Key details/values | Source (URL, year) |
|---|---|---|---|---|
| **Target identity to research** | **Schizosaccharomyces pombe alo1 / SPAPB1A10.12c / UniProt Q9HDX8** | Database-defined target identity from prompt; direct primary-literature evidence not retrieved in available contexts | Target protein is specified as **D-arabinono-1,4-lactone oxidase** / **L-galactono-γ-lactone oxidase** (EC 1.1.3.37), distinct from budding-yeast **ALO1/YML086C**; available paper contexts did **not** provide a direct biochemical characterization for the S. pombe locus, so S. pombe-specific functional claims must be treated cautiously | UniProt accession supplied in user prompt; comparative caution supported by available literature context showing most direct biochemical data are from **S. cerevisiae** rather than **S. pombe** (pqac-00000011, pqac-00000013) |
| **Symbol ambiguity warning: “ALO1” is well characterized in budding yeast and can be confused with S. pombe alo1** | *Saccharomyces cerevisiae* **ALO1 / YML086C** vs. *S. pombe* **alo1 / SPAPB1A10.12c** | Direct experimental evidence for **S. cerevisiae**; cross-species comparison/inference for S. pombe | In **S. cerevisiae**, ALO1 was identified experimentally as ORF **YML086C** encoding the lactone oxidase; this is **not** the same locus designation as S. pombe **SPAPB1A10.12c**. Therefore, literature on YML086C should not be conflated with Q9HDX8 without explicit orthology support | Huh et al. identified **S. cerevisiae ALO1 = YML086C** (https://doi.org/10.1046/j.1365-2958.1998.01133.x, 1998) (pqac-00000011, pqac-00000013) |
| **Core enzymatic function of yeast ALO1 enzymes** | *S. cerevisiae* **ALO1**; inference to *S. pombe* **alo1/Q9HDX8** | Direct biochemical/genetic evidence in ortholog; inference to target based on annotation/name | ALO catalyzes the **terminal oxidation step** in **D-erythroascorbic acid (EASC)** biosynthesis: **D-arabinono-1,4-lactone → D-erythroascorbic acid** | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998); pathway context https://doi.org/10.1016/S0167-4838(98)00217-9 (1998) (pqac-00000011, pqac-00000005, pqac-00000009) |
| **Substrate range is broader than the canonical name implies** | *S. cerevisiae* **ALO1**; inference to *S. pombe* **alo1/Q9HDX8** | Direct enzymology in ortholog | Purified budding-yeast ALO oxidized **D-arabinono-1,4-lactone**, **L-gulono-1,4-lactone**, and **L-galactono-1,4-lactone**; this supports the alternate name **L-galactono-γ-lactone oxidase** and suggests relaxed substrate specificity within aldonolactones | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998) (pqac-00000000, pqac-00000002, pqac-00000013) |
| **Electron acceptor is molecular oxygen** | Yeast D-arabinono-1,4-lactone oxidase (directly discussed for yeast pathway; species example includes *S. cerevisiae*/*Candida*) | Direct pathway/biochemical evidence | Oxidase step uses **O2** as electron acceptor; pathway produces **D-erythroascorbic acid** from **D-arabinono-1,4-lactone** via an oxygen-dependent reaction | https://doi.org/10.1016/S0167-4838(98)00217-9 (1998) (pqac-00000005, pqac-00000009) |
| **Cofactor/family assignment** | *S. cerevisiae* **ALO1**; inference to *S. pombe* **alo1/Q9HDX8** | Direct sequence/biochemical evidence in ortholog; target-family inference from UniProt/domain naming | ALO is a **flavoenzyme** with **covalently bound FAD**; a putative covalent FAD-binding region was mapped to residues **23–56**, with **His56** proposed as the FAD-linked histidine. This is consistent with the oxygen-dependent FAD-linked oxidoreductase family assigned to Q9HDX8 | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998) (pqac-00000000, pqac-00000002, pqac-00000013) |
| **Subcellular localization** | *S. cerevisiae* **ALO1**; inference to *S. pombe* **alo1/Q9HDX8** | Direct biochemical/fractionation and sequence inference in ortholog | ALO was purified from the **mitochondrial fraction**; enzyme activity was assayed in **mitochondrial preparations**; sequence analysis predicted an **integral membrane protein** with a **transmembrane segment (aa 172–188)**, supporting a **mitochondrial membrane** localization in budding yeast | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998) (pqac-00000002, pqac-00000003, pqac-00000013) |
| **Genetic evidence linking ALO1 to EASC production** | *S. cerevisiae* **ALO1** | Direct gene disruption/overexpression evidence | **alo1 deletion** abolished detectable **EASC** and ALO activity; multicopy **ALO1** increased intracellular **EASC ~6.9-fold** and ALO activity **~7.3-fold** | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998) (pqac-00000003, pqac-00000012, pqac-00000018) |
| **Oxidative-stress phenotype** | *S. cerevisiae* **ALO1**; used comparatively in *S. pombe* stress literature | Direct phenotype in ortholog; comparative citation in fission-yeast paper | **alo1 mutants** were hypersensitive to **H2O2** and **menadione**; **ALO1 overexpression** increased survival. Quinn et al. cite budding-yeast **ALO1** as an example of a gene needed for **acute H2O2 resistance** but not apparently for adaptive response | https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998); comparative mention in https://doi.org/10.1091/mbc.01-06-0288 (2002) (pqac-00000001, pqac-00000003, pqac-00000014, pqac-00000020) |
| **Biotechnological application of ALO1 enzyme class** | *S. cerevisiae* **ALO1** | Direct application/engineering evidence | Overexpression of **S. cerevisiae ALO1** enhanced conversion of exogenous lactone precursors toward **L-ascorbic acid**; engineered yeast strains coexpressing pathway enzymes produced about **100 mg/L L-ascorbic acid** from **L-galactose**, illustrating real-world use of ALO enzymes in vitamin C bioproduction | https://doi.org/10.1128/AEM.70.10.6086-6091.2004 (2004) (pqac-00000004, pqac-00000007) |
| **What is directly evidenced for the S. pombe target in available sources** | *S. pombe* **alo1 / SPAPB1A10.12c / Q9HDX8** | Limited direct evidence in retrieved contexts | In the available paper contexts, **no direct biochemical characterization, localization experiment, knockout phenotype, or kinetic data** were retrieved specifically for **S. pombe SPAPB1A10.12c/Q9HDX8**. Therefore, specific functional annotation for the target relies mainly on **UniProt naming/domain assignment** plus **ortholog-based inference** from yeast ALO1 enzymes | Lack of direct target-specific evidence in retrieved contexts; contrast with direct **S. cerevisiae** evidence (pqac-00000011, pqac-00000013, pqac-00000020) |
| **Best-supported annotation strategy for Q9HDX8** | *S. pombe* **alo1 / Q9HDX8** | Evidence synthesis | The most defensible annotation is: **probable mitochondrial, membrane-associated FAD-dependent aldonolactone oxidase** participating in **D-erythroascorbate/vitamin-C-like biosynthesis**, with likely activity on **D-arabinono-1,4-lactone** and possibly **L-galactono-/L-gulono-1,4-lactones**; however, these mechanistic details are **inferred from orthologs**, not directly demonstrated here for S. pombe | Supported by direct budding-yeast enzymology/genetics and comparative oxidative-stress literature: https://doi.org/10.1046/j.1365-2958.1998.01133.x (1998), https://doi.org/10.1016/S0167-4838(98)00217-9 (1998), https://doi.org/10.1128/AEM.70.10.6086-6091.2004 (2004), https://doi.org/10.1091/mbc.01-06-0288 (2002) (pqac-00000000, pqac-00000005, pqac-00000007, pqac-00000020) |


*Table: This table separates what is directly demonstrated for yeast ALO1 enzymes from what can be cautiously inferred for the target S. pombe protein Q9HDX8. It is useful for avoiding symbol confusion and for tracing each functional claim to specific primary sources.*