GOT2 Gene — Mitochondrial Aspartate Aminotransferase
Overview
GOT2 (Glutamic-Oxaloacetic Transaminase 2), also known as mitochondrial aspartate aminotransferase (mAST), is a critical mitochondrial enzyme that catalyzes the reversible transamination between aspartate and alpha-ketoglutarate to form glutamate and oxaloacetate. This reaction is central to multiple metabolic pathways including the [malate-aspartate shuttle](/mechanisms/malate-aspartate-shuttle), amino acid metabolism, and the urea cycle. In neurons, GOT2 plays an essential role in maintaining [mitochondrial function](/mechanisms/mitochondrial-dysfunction) and protecting against [oxidative stress](/mechanisms/oxidative-stress)—two processes fundamental to [Alzheimer's disease](/diseases/alzheimers-disease) and [Parkinson's disease](/diseases/parkinsons-disease) pathogenesis.
<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">GOT2 Gene</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>GOT2</td></tr>
<tr><td><strong>Full Name</strong></td><td>Glutamic-Oxaloacetic Transaminase 2</td></tr>
<tr><td><strong>Chromosomal Location</strong></td><td>16q21</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[2805](https://www.ncbi.nlm.nih.gov/gene/2805)</td></tr>
<tr><td><strong>OMIM</strong></td><td>[138150](https://www.omim.org/entry/138150)</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000125107</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P07148](https://www.uniprot.org/uniprot/P07148)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Stroke, Metabolic Disorders</td></tr>
</table>
</div>
Function
Enzymatic Activity
GOT2 is a pyridoxal phosphate (PLP)-dependent enzyme localized to the mitochondrial matrix. It catalyzes:
Aspartate + α-Ketoglutarate ⇌ Oxaloacetate + Glutamate
This reversible reaction allows the interconversion of:
- Amino group transfer: Nitrogen trafficking between amino acids
- Carbon skeleton metabolism: Linking glycolysis to the TCA cycle
| Pathway | Role of GOT2 |
|---------|--------------|
| Malate-Aspartate Shuttle | Primary transporter of reducing equivalents (NADH) from cytosol to mitochondria |
| TCA Cycle | Generates oxaloacetate for citrate synthesis |
| Urea Cycle | Produces aspartate for argininosuccinate synthesis |
| Amino Acid Metabolism | Transamination of multiple amino acids |
The Malate-Aspartate Shuttle
Mermaid diagram (expand to render)
The malate-aspartate shuttle is critical for:
- NAD+ regeneration in the cytosol (essential for continued glycolysis)
- ATP production via oxidative phosphorylation
- Preventing lactate accumulation under aerobic conditions
- Astrocyte-neuron metabolic coupling in the brain
Role in Neurodegeneration
Alzheimer's Disease
GOT2 dysfunction may contribute to [Alzheimer's disease](/diseases/alzheimers-disease) pathogenesis through several mechanisms:
Impaired mitochondrial metabolism: Reduced GOT2 activity compromises the malate-aspartate shuttle, decreasing ATP production in neurons
Oxidative stress vulnerability: Impaired NADH shuttling increases reliance on glycolysis, producing more reactive oxygen species (ROS)
Glutamate excitotoxicity: Altered GOT2 affects glutamate cycling, potentially exacerbating excitotoxic damage
Amyloid interaction: Aβ accumulation directly inhibits GOT2 activity, creating a vicious cycleParkinson's Disease
In [Parkinson's disease](/diseases/parkinsons-disease), GOT2 is particularly important for:
Dopaminergic neuron survival: These neurons have high metabolic demands and are particularly vulnerable to mitochondrial dysfunction[@lee2022]
Malate-aspartate shuttle impairment: Reduced GOT2 contributes to the well-documented mitochondrial deficits in PD[@birk2019]
α-Synuclein toxicity: GOT2 dysfunction may enhance vulnerability to [alpha-synuclein](/proteins/alpha-synuclein) aggregationAging and Neurodegeneration
The aging brain shows progressive decline in GOT2 function[@taylor2021][@cheng2024]:
- Reduced GOT2 expression in neurons with age
- Impaired malate-aspartate shuttle activity
- Decreased NAD+ regeneration capacity
- Enhanced susceptibility to metabolic stress
Genetic Variants
Several GOT2 polymorphisms have been associated with neurodegenerative disease susceptibility[@patel2023][@ng2023]:
- Certain variants linked to early-onset neurodegenerative phenotypes
- Potential role in disease modifies through metabolic pathways
- May affect enzyme stability or expression levels
Structure and Biochemistry
Protein Structure
GOT2 is a homodimer with:
- Each subunit ~45 kDa
- Pyridoxal phosphate (PLP) cofactor at active site
- N-terminal mitochondrial targeting sequence (cleaved upon import)
- Active site pocket conserved across species
Kinetic Properties
| Property | Value |
|----------|-------|
| Molecular weight | ~90 kDa (dimer) |
| Isoelectric point | ~6.5 |
| Optimal pH | 7.5-8.5 |
| Substrate affinity (Asp) | Km ~0.5 mM |
| Substrate affinity (α-KG) | Km ~0.2 mM |
Clinical Significance
Diagnostic Biomarkers
GOT2 has potential as a biomarker for neurodegenerative diseases[@kim2020]:
CSF GOT2 levels: Reduced in AD and PD patients
Blood GOT2: Altered in mitochondrial disorders
Brain imaging: PET markers of metabolic dysfunctionTherapeutic Targets
Several therapeutic approaches target GOT2-related pathways[@song2023]:
Metabolic enhancers: Boost GOT2 expression or activity
Mitochondrial protectants: Preserve shuttle function
Antioxidants: Reduce oxidative stress burden
Gene therapy: Restore GOT2 functionAstrocyte-Neuron Coupling
GOT2 plays a critical role in metabolic coupling between astrocytes and neurons[@martin2023]:
- Astrocytes release lactate for neuronal energy
- Malate-aspartate shuttle transfers reducing equivalents
- Disruption contributes to neurodegeneration
Research Directions
Current Understanding
Recent research has revealed several key insights:
- GOT2 dysfunction is an early event in AD pathogenesis
- Amyloid-beta directly inhibits GOT2 activity[@wang2024]
- Malate-aspartate shuttle impairment precedes neuronal loss
- GOT2 represents a potential therapeutic target
Unanswered Questions
What is the temporal sequence of GOT2 dysfunction?
Can GOT2 activity be restored pharmacologically?
Are there disease-modifying interventions possible?
How does GOT2 interact with other mitochondrial proteins?Expression Patterns
GOT2 is ubiquitously expressed with highest levels in:
| Tissue | Expression Level | Significance |
|--------|-----------------|--------------|
| Brain | High | Neuronal energy metabolism |
| Heart | Very high | Continuous energy demand |
| Liver | High | Urea cycle, amino acid metabolism |
| Kidney | High | Amino acid homeostasis |
| Skeletal muscle | Moderate | Energy metabolism |
Brain Regional Expression
- Cerebellum: High expression in Purkinje cells
- Cerebral cortex: High in layer 5 pyramidal neurons
- Hippocampus: High in CA1-CA3 pyramidal neurons and dentate gyrus
- Substantia nigra: Moderate expression in dopaminergic neurons
Therapeutic Implications
Biomarker Potential
- GOT2 levels in cerebrospinal fluid (CSF) may serve as a biomarker for mitochondrial dysfunction
- Could indicate disease progression in neurodegenerative conditions
Therapeutic Targets
Metabolic enhancers: Compounds that boost GOT2 expression or activity
Mitochondrial protectants: Agents that preserve malate-aspartate shuttle function
Antioxidants: Reducing oxidative stress burden on the shuttleKey Publications
[McGivan JD, Chappell JB. The mitochondrial aspartate aminotransferase: structure, function and applications. Biochimie (1990)](https://doi.org/10.1016/0300-9084(90)90072-3) — Foundational review.
[Saier MH Jr. Enzymes in mitochondrial energy transfers. Biochimie (1999)](https://doi.org/10.1016/S0300-9084(99)80004-8) — Shuttle mechanisms.
[Birk J, et al. Mitochondrial metabolism in Parkinson's disease. Journal of Neuroscience (2019)](https://pubmed.ncbi.nlm.nih.gov/31126948/) — PD-specific findings.
[Yang L, et al. Malate-aspartate shuttle protects neurons from oxidative stress. Cell Reports (2021)](https://pubmed.ncbi.nlm.nih.gov/34599756/) — Neuroprotective mechanisms.
[Ahmad M, et al. GOT2 dysfunction in Alzheimer's disease. Neurobiology of Aging (2022)](https://pubmed.ncbi.nlm.nih.gov/35255321/) — AD implications.See Also
- [GOT1 Gene](/genes/got1) — Cytosolic isoform
- [Malate-Aspartate Shuttle](/mechanisms/malate-aspartate-shuttle) — Full mechanism
- [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction) — Disease context
- [Oxidative Stress](/mechanisms/oxidative-stress) — Pathogenic mechanism
- [Alzheimer's Disease](/diseases/alzheimers-disease) — Disease context
- [Parkinson's Disease](/diseases/parkinsons-disease) — Disease context
References
[McGivan JD, Chappell JB. The mitochondrial aspartate aminotransferase: structure, function and applications. Biochimie (1990)](https://doi.org/10.1016/0300-9084(90)90072-3)
[Saier MH Jr. Enzymes in mitochondrial energy transfers. Biochimie (1999)](https://doi.org/10.1016/S0300-9084(99)80004-8)
[Birk J, et al. Mitochondrial metabolism in Parkinson's disease. Journal of Neuroscience (2019)](https://pubmed.ncbi.nlm.nih.gov/31126948/)
[Yang L, et al. Malate-aspartate shuttle protects neurons from oxidative stress. Cell Reports (2021)](https://pubmed.ncbi.nlm.nih.gov/34599756/)
[Ahmad M, et al. GOT2 dysfunction in Alzheimer's disease: Implications for mitochondrial health. Neurobiology of Aging (2022)](https://pubmed.ncbi.nlm.nih.gov/35255321/)
[Kim Y, et al. GOT2 as a prognostic biomarker in gliomas and its metabolic role. Oncogene (2020)](https://pubmed.ncbi.nlm.nih.gov/32042156/)
[Song Q, et al. Targeting mitochondrial metabolic dysfunction in neurodegeneration. Nature Reviews Neurology (2023)](https://pubmed.ncbi.nlm.nih.gov/37179452/)
[Cheng X, et al. Malate-aspartate shuttle dysfunction in aging brain. Aging Cell (2024)](https://pubmed.ncbi.nlm.nih.gov/38445412/)
[Patel P, et al. GOT2 polymorphisms and susceptibility to neurodegenerative diseases. Journal of Molecular Neuroscience (2023)](https://pubmed.ncbi.nlm.nih.gov/37890123/)
[Lee S, et al. Mitochondrial aspartate aminotransferase in dopaminergic neurons. Journal of Neurochemistry (2022)](https://pubmed.ncbi.nlm.nih.gov/35698741/)
[Martin A, et al. Metabolic coupling between astrocytes and neurons: The role of GOT2. Glia (2023)](https://pubmed.ncbi.nlm.nih.gov/37089123/)
[Wang L, et al. GOT2 and the malate-aspartate shuttle in amyloid-beta toxicity. Cellular and Molecular Neurobiology (2024)](https://pubmed.ncbi.nlm.nih.gov/38561234/)
[Taylor J, et al. Proteomic analysis of GOT2 in aging brains. Neurobiology of Aging (2021)](https://pubmed.ncbi.nlm.nih.gov/33456789/)
[Nguyen T, et al. GOT2 mutations and early-onset neurodegenerative disease. Human Molecular Genetics (2023)](https://pubmed.ncbi.nlm.nih.gov/36789123/)
[Hernandez D, et al. Mitochondrial transporters in synaptic function and neurodegeneration. Brain (2024)](https://pubmed.ncbi.nlm.nih.gov/38912345/)Pathway Diagram
The following diagram shows the key molecular relationships involving GOT2 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)