N-acetylglutamate synthase (NAGS; amino-acid acetyltransferase, EC 2.3.1.1) of Saccharomyces cerevisiae, a mitochondrial matrix enzyme that acetylates L-glutamate with acetyl-CoA to form N-acetyl-L-glutamate, the first step of the acetylated (ornithine-producing) branch of arginine biosynthesis. Like other fungal NAGS it is unrelated in sequence to bacterial ArgA. Arg2 is active only in a stoichiometric complex (metabolon) with the acetylglutamate kinase domain of Arg5,6; complex formation is required for synthase activity and stability and couples arginine feedback inhibition of NAGS and NAGK, the two flux-controlling steps of the pathway. Arg2 provides the anaplerotic supply of N-acetylglutamate, which is otherwise recycled by ornithine acetyltransferase (Arg7). The kinase-associated domain is required for synthase activity, while the separate reductase product is dispensable for this support.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004042 L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor | EXP PMID:391804 Regulation of activity and synthesis of N-acetylglutamate sy... | ACCEPT | Summary: N-acetylglutamate synthase activity measured in a particulate yeast fraction, including arginine feedback inhibition and regulation of enzyme synthesis. Supporting Evidence: PMID:391804 Feedback inhibition of N-acetylgutamate synthase in a particulate fraction from Saccharomyces cerevisiae by L-arginine |
| GO:0004042 L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor | IBA GO_REF:0000033 | ACCEPT | Summary: Acetyl-CoA-dependent N-acetylglutamate synthase activity; ARG2 itself is among the experimental descendants. Core function. Supporting Evidence: file:yeast/ARG2/ARG2-uniprot.txt Reaction=L-glutamate + acetyl-CoA = N-acetyl-L-glutamate + CoA + H(+); |
| GO:0004042 L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor | IDA PMID:11553611 A new yeast metabolon involving at least the two first enzym... | ACCEPT | Summary: Synthase activity assayed for ARG2 (YJL071W) and shown to depend on the Arg5,6 kinase. Core function. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis PMID:11553611 The results imply that the synthase must interact stoichiometrically in vivo with the kinase, the reductase, or both to be active. |
| GO:0004042 L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor | IEA GO_REF:0000120 | ACCEPT | Summary: Automated RHEA/InterPro assignment consistent with experiment. Core function. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis. |
| GO:0004042 L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor | IMP PMID:11553611 A new yeast metabolon involving at least the two first enzym... | ACCEPT | Summary: Gene-dosage/mutant analysis shows ARG2 encodes the synthase activity. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0005739 mitochondrion | EXP PMID:205532 Arginine metabolism in Saccharomyces cerevisiae: subcellular... | ACCEPT | Summary: ARG2 has supported mitochondrial localization; the matrix assertion is retained separately. Reason: The fractionation study measured the acetylated ornithine-pathway enzyme activities in particulate fractions and compared their distribution with mitochondrial markers. This directly supports the organelle location. The root-organelle policy preserves mitochondrion as an informative claim. Matrix localization was checked and remains a separate annotation, with its own experimental or inference basis. Supporting Evidence: PMID:205532 These enzymes were exclusively particulate. PMID:205532 suggested that these enzymes were associated with the mitochondria |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: ARG2 has supported mitochondrial localization; the matrix assertion is retained separately. Reason: The electronic compartment assignment agrees with the publication-linked curated target localization and existing experimental mitochondrial annotations. Its source stops at the organelle and is retained at that level. The root-organelle policy preserves mitochondrion as an informative claim. Matrix localization was checked and remains a separate annotation, with its own experimental or inference basis. Supporting Evidence: PMID:205532 These enzymes were exclusively particulate. PMID:205532 suggested that these enzymes were associated with the mitochondria |
| GO:0005759 mitochondrial matrix | IBA GO_REF:0000033 | ACCEPT | Summary: Mitochondrial matrix location; consistent with fractionation data. Supporting Evidence: PMID:205532 These enzymes were exclusively particulate. |
| GO:0005759 mitochondrial matrix | IDA PMID:205532 Arginine metabolism in Saccharomyces cerevisiae: subcellular... | ACCEPT | Summary: Fractionation associated acetylglutamate synthase with mitochondria; curator assigned the matrix compartment from the full text. Supporting Evidence: PMID:205532 suggested that these enzymes were associated with the mitochondria |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: YeastPathways-derived (GO_REF:0000123) location assigning activity to the cytosol. This enzyme of the acetylated (ornithine-producing) part of the yeast arginine pathway is a mitochondrial matrix protein, shown by subcellular fractionation and by the cleaved mitochondrial presequence; the cytosol term contradicts the experimental location data. Reason: PMID:205532 explicitly included acetylglutamate synthase among the measured activities restricted to particulate fractions, distinguished from the soluble downstream arginine-pathway enzymes. This is direct biochemical compartment discrimination for the target activity, not rejection from a targeting peptide or absence of a cytosolic database entry. It supports rejecting the pathway-derived cytosolic assignment under the measured native conditions; it does not prove that no precursor molecule or minor conditional pool can ever occur outside mitochondria. Unlike ARG7, no target-specific pre-import autocatalysis is established in the inspected evidence. Supporting Evidence: PMID:205532 These enzymes were exclusively particulate. PMID:205532 suggested that these enzymes were associated with the mitochondria |
| GO:0006526 L-arginine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: First step of arginine biosynthesis. Core process. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0006526 L-arginine biosynthetic process | IDA PMID:11553611 A new yeast metabolon involving at least the two first enzym... | ACCEPT | Summary: ARG2 identified as the structural gene for the first step of arginine biosynthesis. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0006526 L-arginine biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: Automated pathway assignment; correct. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0006526 L-arginine biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways assignment; correct. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0006592 L-ornithine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: N-acetylglutamate synthesis is the first step of the acetylated route that produces ornithine (the ornithine-producing segment of the arginine pathway). Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0006592 L-ornithine biosynthetic process | IMP PMID:11553611 A new yeast metabolon involving at least the two first enzym... | ACCEPT | Summary: Mutant analysis places ARG2 in the ornithine-producing segment of the pathway. Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis |
| GO:0103045 L-methionine N-acyltransferase activity | RCA GO_REF:0000123 | MODIFY | Summary: The acetyl-cycle pathway assignment supports glutamate acetylation rather than a methionine-specific reaction. Reason: The proximate source is SGD_PWY:ARGSYNBSUB-PWY, the arginine acetyl-cycle pathway. Its initiating acetyl-transfer step uses L-glutamate. Target-specific work establishes acetyl-CoA-dependent N-acetylglutamate synthesis; replace this methionine-acceptor assignment with the existing GO:0004042. This is a pathway/reaction-specificity correction, not a claim that all possible side-substrate activities have been experimentally excluded. Proposed replacements: L-glutamate N-acetyltransferase activity, acting on acetyl-CoA as donor Supporting Evidence: PMID:11553611 Open reading frame YJL071W of Saccharomyces cerevisiae was shown to be ARG2 and identified as the structural gene for acetylglutamate synthase, first step in arginine biosynthesis. |
| GO:0106098 NAGS/NAGK complex | IPI PMID:11553611 A new yeast metabolon involving at least the two first enzym... | ACCEPT | Summary: HA-tagged Arg2 co-immunoprecipitated the Arg5,6-derived kinase, and synthase activity requires stoichiometric complex formation. Core complex membership. Supporting Evidence: PMID:11553611 hemagglutinin-tagged synthase coprecipitated with a protein proven by microsequencing to be the kinase PMID:11553611 The results imply that the synthase must interact stoichiometrically in vivo with the kinase, the reductase, or both to be active. |
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Download this section (compressed HTML)Acetylglutamate synthase (glutamate N-acetyltransferase); mitochondrial enzyme that catalyzes the first step in the biosynthesis of the arginine precursor ornithine; forms a complex with Arg5,6p
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