GO_REF:0000002

GO reference used by source annotation pipeline

GO_REF:0000024

GO reference used by source annotation pipeline

GO_REF:0000033

GO reference used by source annotation pipeline

GO_REF:0000044

GO reference used by source annotation pipeline

GO_REF:0000117

GO reference used by source annotation pipeline

GO_REF:0000120

GO reference used by source annotation pipeline

GO_REF:0000121

GO reference used by source annotation pipeline

PMID:18621030

N-acetylaspartate synthesis in the brain: mitochondria vs. microsomes

In rat (and bovine) brain homogenates, the majority of Asp-NAT (NAA-synthesizing) activity fractionates with mitochondria rather than microsomes, supporting a predominantly mitochondrial localization for NAA biosynthesis, with the enzyme eluting as a high-molecular-weight (~670 kD) species.

"We found that about 70% of the total Asp-NAT activity in the crude supernatant was present in the mitochondrial fraction which is about 5 times more than that in the microsomes."

file:rat/Nat8l/Nat8l-deep-research-falcon.md

Falcon (Edison Scientific) deep research report: rat Nat8l / N-acetylaspartate synthetase (UniProt D3ZVU9)

Nat8l encodes N-acetylaspartate synthetase (Asp-NAT; EC 2.3.1.17), which synthesizes N-acetylaspartate (NAA) from acetyl-CoA and L-aspartate; this is the gene's primary molecular function.

"*Rattus norvegicus* **Nat8l** encodes **N-acetylaspartate synthetase / aspartate N-acetyltransferase (NAT8L; Asp-NAT; EC 2.3.1.17)**, the enzyme that synthesizes **N-acetylaspartate (NAA)** from **acetyl‑CoA** and **L‑aspartate**."
The catalyzed reaction is acetyl-CoA + L-aspartate -> CoA + N-acetyl-L-aspartate, with high substrate selectivity for aspartate over related amino acids.

"**Substrate specificity:** NAT8L/Asp-NAT is reported to be highly selective for **aspartate**. Enzymology summarized by Moffett et al. indicates **<3% activity** with glutamate/asparagine/glutamine compared with aspartate (stringent specificity), and also notes an approximately **~10-fold preference** for aspartate over glutamate in other reports."
Subcellular localization is unresolved: NAT8L is membrane-associated with microsomal/ER-associated and mitochondrial-associated pools, and this uncertainty should be preserved rather than collapsed to a single compartment.

"**Localization remains somewhat mixed across experimental approaches**, but NAT8L is consistently described as a membrane-associated enzyme with **microsomal/ER-associated and mitochondrial-associated pools**."
Localization across ER/microsome versus mitochondria remains actively debated and should be preserved as uncertainty in functional annotation.

"NAT8L’s **precise subcellular localization** (ER/microsome vs mitochondria, or dual) and **native complex organization** remain debated, with evidence supporting multiple fractions and large complexes"
In the CNS, NAT8L is predominantly a neuronal enzyme producing NAA, which is catabolized by oligodendroglial ASPA to acetate supporting acetyl-CoA and myelin lipid synthesis.

"**NAT8L/Asp-NAT:** The enzyme catalyzing NAA synthesis from acetyl-CoA and aspartate. This places NAT8L at the intersection of mitochondrial acetyl-CoA availability, aspartate metabolism, and intercellular acetate trafficking hypotheses relevant to myelination and acetylation homeostasis."
Downstream NAA is hydrolyzed by ASPA to acetate plus aspartate, linking NAT8L to acetate/acetyl-CoA metabolism and lipid/myelin synthesis.

"NAT8L initiates the **NAA pathway** in neurons. NAA is transferred to oligodendrocytes, where **ASPA hydrolyzes NAA → acetate + aspartate**; acetate supports **acetyl-CoA**, **lipid/myelin synthesis**, and acetylation reactions."