| Property | Human NAGS summary |
|---|---|
| Gene symbol | **NAGS** (N-acetylglutamate synthase) (pqac-00000008, pqac-00000031) |
| UniProt accession | **Q8N159** |
| EC number | **EC 2.3.1.1** (pqac-00000003, pqac-00000044) |
| Enzyme classification | **Acetyltransferase**; specifically an N-acetylglutamate synthase in the acetyltransferase family (pqac-00000006, pqac-00000031) |
| Reaction catalyzed | **L-glutamate + acetyl-CoA → N-acetylglutamate (NAG) + CoA** (pqac-00000003, pqac-00000005, pqac-00000006) |
| Substrates | **L-glutamate** and **acetyl-CoA**; human enzyme shows high specificity for these substrates (pqac-00000001, pqac-00000006) |
| Product | **N-acetylglutamate (NAG)**, the essential allosteric activator of CPS1 (pqac-00000003, pqac-00000019) |
| Allosteric activator | **L-arginine**; activates mammalian NAGS about **2–5-fold**, with **Ka ~30–50 µM** (pqac-00000019, pqac-00000023) |
| Km for glutamate | Reported range **~1–8.1 mM** depending on preparation/assay system (pqac-00000001) |
| Km for acetyl-CoA | Reported range **~0.7–4.4 mM** depending on preparation/assay system (pqac-00000001) |
| Subcellular localization | **Mitochondrial matrix** (pqac-00000003, pqac-00000008, pqac-00000012) |
| Tissue expression | Highest in **liver** and **small intestine**; lower expression reported in **kidney, testis, spleen** (pqac-00000008) |
| Protein length | **534 aa preprotein** with N-terminal mitochondrial targeting sequence (pqac-00000008, pqac-00000014) |
| Domain architecture | N-terminal **AAK (amino acid kinase-like) domain** plus C-terminal **NAT/GNAT acetyltransferase domain**; also contains an N-terminal variable segment (pqac-00000027, pqac-00000029, pqac-00000031) |
| Oligomeric state | Reported as **trimeric** in some studies, with evidence for arginine-dependent oligomerization behavior; vertebrate-like NAGS family members also discussed in relation to **tetrameric** organization/models (pqac-00000023, pqac-00000028) |
| Disease association | **NAGS deficiency (NAGSD)** causing **hyperammonemia** / urea cycle dysfunction; strong disease-target association in Open Targets (pqac-00000035, pqac-00000037, pqac-00000000) |
| Drug / functional replacement therapy | **N-carbamylglutamate (carglumic acid / carbamylglutamate)**, a stable NAG analog that activates CPS1 and can normalize ammonia in NAGSD (pqac-00000038, pqac-00000040, pqac-00000042) |


*Table: This table summarizes core biochemical, cellular, and clinical properties of human NAGS, including its catalytic reaction, regulation, localization, and disease relevance. It is useful as a compact reference for the functional annotation of UniProt Q8N159.*