arg41 (SPBC1539.03c; UniProt gene name argx) encodes an argininosuccinate lyase (EC 4.3.2.1) of the lyase 1 family, orthologous to S. cerevisiae ARG4. It cleaves 2-(N-omega-L-arginino)succinate into L-arginine and fumarate, the final step of arginine biosynthesis, and acts in the cytosol. S. pombe has a second argininosuccinate lyase paralog, arg7 (SPBC1773.14); deletion of arg41 causes arginine auxotrophy whereas deletion of arg7 does not, showing a requirement for arg41 under the tested conditions, without quantifying the relative catalytic flux through the two paralogs. The catalytic activity is inferred from sequence; it has not been assayed for the purified S. pombe protein.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000050 urea cycle | IC GO_REF:0000111 | KEEP AS NON CORE | Summary: This enzyme performs a shared ornithine-to-arginine reaction within the fungal arginine/urea reaction network. Reason: Live GO:0000050 defines ornithine-to-arginine synthesis followed by arginine cleavage to urea and regenerated ornithine; it does not require a ureotelic organism or nitrogen excretion. The target has the annotated OTC/ASS/ASL reaction and native fungal arginase supplies the return chemistry. Retain the existing process annotation as a contextual role, without asserting measured net full-cycle flux or a metazoan detoxification function. The primary role remains arginine biosynthesis. PMID:20435771 directly measures S. pombe Car1/Car3 arginase activity and urea production. Supporting Evidence: PMID:20435771 arginase catalyzes the degradation of arginine into urea and ornithine. |
| GO:0000050 urea cycle | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: This enzyme performs a shared ornithine-to-arginine reaction within the fungal arginine/urea reaction network. Reason: Live GO:0000050 defines ornithine-to-arginine synthesis followed by arginine cleavage to urea and regenerated ornithine; it does not require a ureotelic organism or nitrogen excretion. The target has the annotated OTC/ASS/ASL reaction and native fungal arginase supplies the return chemistry. Retain the existing process annotation as a contextual role, without asserting measured net full-cycle flux or a metazoan detoxification function. The primary role remains arginine biosynthesis. PMID:20435771 directly measures S. pombe Car1/Car3 arginase activity and urea production. Supporting Evidence: PMID:20435771 arginase catalyzes the degradation of arginine into urea and ornithine. |
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO (IPR008948 L-aspartase-like, IPR020557 fumarate lyase signature) mapping to catalytic activity. Reason: Uninformative root-level term; the specific activity is argininosuccinate lyase. Proposed replacements: argininosuccinate lyase activity Supporting Evidence: file:SCHPO/arg41/arg41-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; file:SCHPO/arg41/arg41-uniprot.txt SIMILARITY: Belongs to the lyase 1 family. Argininosuccinate lyase |
| GO:0004056 argininosuccinate lyase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for argininosuccinate lyase (node PTN000154674) with S. cerevisiae ARG4, rat Asl and the S. pombe paralog arg7 among sources. Reason: arg41 retains the lyase 1 catalytic residues and is genetically required for arginine synthesis. Supporting Evidence: file:SCHPO/arg41/arg41-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; PMID:32896087 arg7 is one of two argininosuccinate lyases (with deletion of the other one, arg41, showing arginine auxotrophy) |
| GO:0004056 argininosuccinate lyase activity | IEA GO_REF:0000120 | ACCEPT | Summary: InterPro (IPR009049) / Rhea 24020 / EC 4.3.2.1 mapping to argininosuccinate lyase activity. Reason: Correct activity. Supporting Evidence: file:SCHPO/arg41/arg41-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; |
| GO:0005829 cytosol | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: Cytosolic signal for arg41 in the ORFeome localisation screen. Reason: Consistent with the cytosolic final steps of fungal arginine biosynthesis. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for cytosol (S. cerevisiae ARG4 source). Reason: Correct, corroborated by HDA. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0006526 L-arginine biosynthetic process | EXP PMID:32896087 Mitochondrial respiration is required to provide amino acids... | ACCEPT | Summary: Malecki et al. 2020 report that deletion of arg41, but not of its paralog arg7, causes arginine auxotrophy. Reason: Direct deletion phenotype establishes a requirement for arg41 under the tested growth conditions; it does not quantify its share of total lyase activity or negate independently supported arg7 function. Supporting Evidence: PMID:32896087 arg7 is one of two argininosuccinate lyases (with deletion of the other one, arg41, showing arginine auxotrophy) |
| GO:0006526 L-arginine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for L-arginine biosynthetic process (node PTN000154674); arg41 (SPBC1539.03c) itself is among the sources. Reason: Correct and experimentally grounded. Supporting Evidence: PMID:32896087 arg7 is one of two argininosuccinate lyases (with deletion of the other one, arg41, showing arginine auxotrophy) |
| GO:0006526 L-arginine biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: ARBA/InterPro/UniPathway mapping to L-arginine biosynthetic process. Reason: Correct pathway. Supporting Evidence: file:SCHPO/arg41/arg41-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; |
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Download this section (compressed HTML)Q: What is the role of the second argininosuccinate lyase paralog arg7, whose deletion does not cause auxotrophy: redundant low-level activity, a different expression condition, or a divergent function?
Q: How much native argininosuccinate lyase flux is carried by Arg41 versus Arg7 under different growth conditions? The deletion phenotype establishes a condition-specific requirement, while the catalytic assignment also relies on conserved lyase architecture and phylogenetic inference.
Experiment: Assay argininosuccinate lyase activity in extracts of arg41 and arg7 single and double deletions, and test complementation of arg41 deletion by arg7 overexpression.
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