GO:0120568 (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0120568 defines the molecular function that catalyzes the NAD+-dependent oxidation of (R)-2-hydroxyglutarate to 2-oxoglutarate.
• The enzyme is stereospecific for the (R)-enantiomer and uses NAD+ as the electron acceptor, producing NADH and H+.
• Structural studies of the Acidaminococcus fermentans enzyme revealed a conserved catalytic mechanism involving a catalytic base and a Rossmann-fold NAD+ binding domain.
• The activity is widely used as a coupled assay for aminotransferases and for detecting (R)-2-hydroxyglutarate in metabolic studies.
• Dysregulation of (R)-2-hydroxyglutarate metabolism is linked to oncometabolite accumulation, pseudohypoxia, and altered DNA repair.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable precise interrogation of this activity in cancer and metabolic disease.
Description
GO:0120568, (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity, is a molecular function that catalyzes the reversible NAD+-dependent conversion of (R)-2-hydroxyglutarate to 2-oxoglutarate. This activity is central to the metabolism of the oncometabolite (R)-2-hydroxyglutarate and provides a direct enzymatic route for its clearance or production depending on cellular context. The enzyme is stereospecific, acting only on the (R)-enantiomer, and requires NAD+ as a cofactor, yielding NADH and a proton. Because of its strict substrate specificity, this activity has become a valuable tool in biochemical assays, particularly for measuring aminotransferase reactions through coupled enzymatic detection. Researchers study GO:0120568 to understand how cells maintain 2-hydroxyglutarate homeostasis and how disruptions contribute to disease. The enzyme was first characterized structurally in Acidaminococcus fermentans, revealing a Rossmann-fold NAD+ binding domain and a catalytic mechanism that ensures stereo-specific hydride transfer. Beyond its role in microbial fermentation, the activity is relevant to human cancer biology because (R)-2-hydroxyglutarate acts as an oncometabolite that inhibits alpha-ketoglutarate-dependent dioxygenases, leading to pseudohypoxia and epigenetic changes. Recent work shows that (R)-2-hydroxyglutarate can suppress DNA polymerase beta, enhancing sensitivity to alkylating agents and PARG inhibition. Thus, understanding this enzymatic activity is critical for metabolic engineering, drug discovery, and cancer research. The importance of GO:0120568 extends to assay development and diagnostics. A continuous assay for aminotransferases was developed by coupling their reactions to (R)-2-hydroxyglutarate dehydrogenase, enabling real-time monitoring of enzyme activity. Additionally, acidic pH has been identified as a metabolic switch that promotes 2-hydroxyglutarate generation and signaling, highlighting the interplay between cellular environment and this enzyme's function. These findings underscore the broad utility of studying this activity in both basic and translational research.
(R)-2-hydroxyglutarate (NAD+) dehydrogenase activity At A Glance
| GO ID | GO:0120568 |
|---|---|
| GO term | (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity |
| Ontology | molecular_function |
| Synonym | 2-oxoglutarate reductase activity |
| Definition | Catalysis of the reaction: (R)-2-hydroxyglutarate + NAD+ = 2-oxoglutarate + NADH + H+. |
| Major function | NAD+-dependent oxidation of (R)-2-hydroxyglutarate to 2-oxoglutarate |
| Cofactor | NAD+ |
| Substrate specificity | Strictly (R)-2-hydroxyglutarate |
| Reaction direction | Reversible |
| Structural fold | Rossmann-fold NAD+ binding domain |
What Is GO:0120568?
GO:0120568 describes the catalysis of the reaction: (R)-2-hydroxyglutarate + NAD+ = 2-oxoglutarate + NADH + H+. In other words, it is the enzyme activity that removes a hydride from (R)-2-hydroxyglutarate and transfers it to NAD+, forming NADH and 2-oxoglutarate. The reaction is reversible and strictly specific for the (R)-stereoisomer of 2-hydroxyglutarate, distinguishing it from other dehydrogenases. The synonym 2-oxoglutarate reductase activity reflects the reverse reaction direction.
Why Is (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity Important in Cell Biology?
GO:0120568 is important because it governs the cellular levels of (R)-2-hydroxyglutarate, an oncometabolite that inhibits alpha-ketoglutarate-dependent dioxygenases and contributes to pseudohypoxia, epigenetic reprogramming, and altered DNA repair. The enzyme also serves as a critical tool in biochemical assays for aminotransferase activity, enabling high-throughput screening and metabolic studies. Understanding its regulation and catalytic mechanism can inform therapeutic strategies targeting 2-hydroxyglutarate-related pathways in cancer and metabolic disorders.
• Regulates (R)-2-hydroxyglutarate levels, a key oncometabolite in cancer.
• Provides a stereospecific enzymatic tool for detecting (R)-2-hydroxyglutarate in biological samples.
• Enables continuous coupled assays for aminotransferases, facilitating drug discovery.
• Links to pseudohypoxic signaling and aging-related pathways.
• Modulates DNA repair by influencing DNA polymerase beta levels.
• Potential target for metabolic engineering of 2-hydroxyglutarate production.
• Relevant to microbial fermentation pathways, as shown in Acidaminococcus fermentans.
• Acidic pH can switch 2-hydroxyglutarate generation and signaling, affecting enzyme activity.
• Structural insights guide inhibitor design and mechanistic studies.
• CRISPR models allow functional dissection of this activity in disease contexts.
Molecular Mechanism of (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity
Substrate Binding and Stereospecificity
In simple terms: The enzyme recognizes only the (R)-form of 2-hydroxyglutarate, like a lock that fits only one key.
The enzyme binds (R)-2-hydroxyglutarate in a stereospecific pocket that excludes the (S)-enantiomer. Structural analysis of the Acidaminococcus fermentans enzyme revealed a conserved arginine residue that interacts with the substrate's carboxylate groups, ensuring strict (R)-selectivity. This specificity is critical for avoiding cross-reactivity with other hydroxyacids such as (S)-2-hydroxyglutarate or lactate.
NAD+ Binding and Hydride Transfer
In simple terms: NAD+ acts as a shuttle that carries electrons away from the substrate.
The enzyme contains a Rossmann-fold domain that binds NAD+ in an extended conformation. The catalytic mechanism involves a hydride transfer from the C2 position of (R)-2-hydroxyglutarate to the nicotinamide ring of NAD+, forming NADH and 2-oxoglutarate. A conserved catalytic base, likely a histidine or aspartate, abstracts a proton from the substrate's hydroxyl group to facilitate the reaction.
Reaction Reversibility and 2-Oxoglutarate Reduction
In simple terms: The reaction can run backwards, turning 2-oxoglutarate back into (R)-2-hydroxyglutarate.
The enzyme also catalyzes the reverse reaction, known as 2-oxoglutarate reductase activity, using NADH to reduce 2-oxoglutarate to (R)-2-hydroxyglutarate. This reversibility allows the enzyme to participate in both catabolic and anabolic pathways depending on cellular redox state and substrate availability. The equilibrium favors the oxidative direction under standard conditions, but can shift based on NAD+/NADH ratios.
Cofactor Regeneration and Assay Coupling
In simple terms: The NADH produced can be measured to track enzyme activity in real time.
Because the reaction produces NADH, which absorbs light at 340 nm, the activity can be monitored spectrophotometrically. This property was exploited to develop a continuous assay for aminotransferases by coupling their reactions to (R)-2-hydroxyglutarate dehydrogenase. The assay uses the enzyme to convert (R)-2-hydroxyglutarate generated by aminotransferase activity into 2-oxoglutarate, producing NADH that is continuously measured.
Regulation by pH and Metabolic Context
In simple terms: The enzyme works differently depending on how acidic the cell environment is.
Acidic pH has been shown to act as a metabolic switch for 2-hydroxyglutarate generation and signaling. Under acidic conditions, the enzyme's activity may be modulated to favor production or clearance of (R)-2-hydroxyglutarate, impacting downstream signaling pathways. This pH sensitivity links the enzyme to tumor microenvironment and metabolic stress responses.
Key Genes Involved in GO:0120568 (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity
The following genes and proteins are directly or indirectly associated with (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity, based on published biochemical and structural studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| Acidaminococcus fermentans (R)-2-hydroxyglutarate dehydrogenase | Catalyzes the NAD+-dependent oxidation of (R)-2-hydroxyglutarate | Structural model for stereospecific catalysis |
| Rhodospirillum rubrum D-alpha-hydroxyglutarate dehydrogenase | Oxidizes D-alpha-hydroxyglutarate | Early characterization of the activity |
| Clostridium propionicum (R)-lactate dehydratase | Related dehydration step in fermentation | Context for (R)-2-hydroxyglutarate metabolism |
| LDHA | Lactate dehydrogenase, produces NADH | Indirect redox coupling |
| MDH1/2 | Malate dehydrogenase, NAD+ dependent | Related dehydrogenase family |
| IDH1/2 | Isocitrate dehydrogenase, produces 2-oxoglutarate | Links to 2-hydroxyglutarate metabolism |
| L2HGDH | Mitochondrial (R)-2-hydroxyglutarate dehydrogenase | Human enzyme with similar activity |
| D2HGDH | D-2-hydroxyglutarate dehydrogenase | Related but distinct stereospecificity |
| GOT1/2 | Aspartate aminotransferase, coupled assay target | Assay development |
| GPT | Alanine aminotransferase, coupled assay target | Assay development |
| POLB | DNA polymerase beta, suppressed by 2-HG | DNA repair link |
| PARG | Poly(ADP-ribose) glycohydrolase, inhibited with 2-HG | Synthetic lethality |
| HIF1A | Hypoxia-inducible factor, stabilized by 2-HG | Pseudohypoxia |
| TET2 | DNA demethylase, inhibited by 2-HG | Epigenetic regulation |
| KDM4A | Histone demethylase, inhibited by 2-HG | Epigenetic regulation |
| EGLN1 | Prolyl hydroxylase, inhibited by 2-HG | Pseudohypoxia |
| SLC25A1 | Mitochondrial citrate carrier | Metabolic context |
| GLUD1 | Glutamate dehydrogenase, produces 2-oxoglutarate | Substrate supply |
How Is (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity Regulated?
The activity of (R)-2-hydroxyglutarate (NAD+) dehydrogenase is regulated at multiple levels. The enzyme's expression and activity can be influenced by cellular redox state, as it depends on NAD+ availability. Acidic pH acts as a metabolic switch that promotes 2-hydroxyglutarate generation and signaling, potentially altering enzyme flux. Additionally, the enzyme's reversible nature allows it to respond to changes in substrate concentrations, such as 2-oxoglutarate and (R)-2-hydroxyglutarate, which are influenced by other metabolic pathways including IDH mutations and glutaminolysis. No direct transcriptional regulators have been definitively established for the Acidaminococcus enzyme, but in human cells, the related L2HGDH is subject to mitochondrial regulation.
(R)-2-hydroxyglutarate (NAD+) dehydrogenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| IDH1/2 | Glioma, AML, oncometabolite production | Knock-in of mutant IDH1 in cell lines |
| L2HGDH | L-2-hydroxyglutaric aciduria | Knockout in HEK293 or patient fibroblasts |
| POLB | DNA repair deficiency, chemosensitivity | Overexpression or knockout in cancer cells |
| HIF1A | Pseudohypoxia, angiogenesis | Reporter assays under 2-HG treatment |
| TET2 | Epigenetic dysregulation | CRISPR knockout in hematopoietic cells |
(R)-2-Hydroxyglutarate as an Oncometabolite
Dysregulation of (R)-2-hydroxyglutarate metabolism leads to its accumulation, which acts as an oncometabolite. High levels of (R)-2-hydroxyglutarate inhibit alpha-ketoglutarate-dependent dioxygenases, including TET2 and KDM4A, resulting in DNA and histone hypermethylation. This epigenetic reprogramming contributes to tumorigenesis in gliomas and acute myeloid leukemia. The enzyme GO:0120568 can clear (R)-2-hydroxyglutarate, so its loss of function may exacerbate oncometabolite accumulation.
Pseudohypoxia and Aging
(R)-2-hydroxyglutarate stabilizes HIF1A by inhibiting prolyl hydroxylases, leading to pseudohypoxic signaling even under normoxic conditions. This pseudohypoxic state is associated with aging-related pathways and cancer progression. The enzyme's role in degrading (R)-2-hydroxyglutarate suggests that enhancing its activity could counteract pseudohypoxia.
DNA Repair and Chemosensitivity
Recent studies show that (R)-2-hydroxyglutarate suppresses basal protein levels of DNA polymerase beta, enhancing cytotoxicity induced by alkylating agents and PARG inhibition. This link between (R)-2-hydroxyglutarate and DNA repair suggests that modulating GO:0120568 activity could sensitize tumors to DNA-damaging therapies.
From (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of (R)-2-hydroxyglutarate dehydrogenase increase oncometabolite levels? | CRISPR knockout of L2HGDH in cancer cell lines |
| Can a point mutation abolish stereospecificity? | Point mutation at catalytic residues (e.g., Arg) in Acidaminococcus enzyme |
| Does overexpression reduce (R)-2-hydroxyglutarate and reverse pseudohypoxia? | Knock-in of constitutive promoter driving dehydrogenase |
| Where is the enzyme localized in cells? | Tagged knock-in with GFP or FLAG |
| What is the effect of acidic pH on enzyme activity? | Overexpression in cells cultured at varying pH |
| Can the enzyme be used as a coupled assay reporter? | Purified enzyme or lysates overexpressing the dehydrogenase |
How to Study the (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADH absorbance assay | Enzyme activity via NADH production | Kinetic characterization, inhibitor screening |
| X-ray crystallography | Three-dimensional structure | Active site mapping, stereospecificity |
| LC-MS metabolomics | Intracellular (R)-2-hydroxyglutarate and 2-oxoglutarate | Metabolic flux analysis |
| CRISPR knockout screening | Gene essentiality and resistance | Identifying modifiers of 2-HG toxicity |
| Western blot | Protein expression levels | Validating knockout or overexpression |
| Immunofluorescence | Subcellular localization | Tagged knock-in models |
| Enzyme-coupled aminotransferase assay | Aminotransferase activity | Diagnostics and drug discovery |
Enzymatic Activity Assays
The NADH produced by GO:0120568 can be measured spectrophotometrically at 340 nm. This principle underlies a continuous assay for aminotransferases, where the dehydrogenase couples the production of (R)-2-hydroxyglutarate to NADH formation. Such assays are used for high-throughput screening of enzyme inhibitors or for characterizing mutant enzymes.
Structural Biology
X-ray crystallography and cryo-EM can resolve the enzyme's active site and cofactor binding. The structure of the Acidaminococcus fermentans enzyme revealed a Rossmann-fold and a catalytic mechanism for stereospecific hydride transfer. These methods guide rational design of inhibitors or engineered variants.
Metabolomics and Isotope Tracing
Mass spectrometry-based metabolomics can quantify (R)-2-hydroxyglutarate and 2-oxoglutarate levels in cells or tissues. Isotope-labeled substrates (e.g., 13C-glutamine) trace flux through the dehydrogenase reaction, revealing its contribution to metabolic networks.
CRISPR Screening and Functional Genomics
Genome-wide CRISPR knockout screens can identify genes that modulate (R)-2-hydroxyglutarate sensitivity or dehydrogenase activity. Such screens link the enzyme to pathways like DNA repair and pseudohypoxia.
How CRISPR Can Be Used to Study GO:0120568 (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity
Knockout
CRISPR knockout of the gene encoding (R)-2-hydroxyglutarate (NAD+) dehydrogenase can abolish its activity, leading to accumulation of (R)-2-hydroxyglutarate. This model is useful to study the metabolic and epigenetic consequences of losing this activity, such as increased pseudohypoxia or DNA repair defects.
Point Mutation
Introducing point mutations at catalytic residues (e.g., the conserved arginine or histidine) can dissect the mechanism of stereospecific catalysis. Such mutants can be expressed in cells to test whether a single amino acid change abolishes activity without affecting protein stability.
Knock-in
Knock-in of a tagged version (e.g., GFP or FLAG) allows visualization and immunoprecipitation of the enzyme. This approach helps determine subcellular localization and interaction partners under native expression levels.
Overexpression
Overexpression of the dehydrogenase can lower (R)-2-hydroxyglutarate levels and reverse oncometabolite-induced phenotypes. This model is valuable to test whether enhancing enzyme activity can suppress pseudohypoxia or sensitize cells to therapy.
How EDITGENE Supports (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity Research
Researchers studying (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity-related genes often need to determine whether a candidate gene is causally involved in metabolic regulation, oncometabolite clearance, or drug response. EDITGENE provides custom CRISPR cell models to interrogate this activity with precision.
Contact EDITGENE today to design your custom CRISPR model for (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity research.
Frequently Asked Questions About (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity
What is (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity?
It is the enzyme activity defined by GO:0120568 that catalyzes the NAD+-dependent oxidation of (R)-2-hydroxyglutarate to 2-oxoglutarate, producing NADH and H+.
What genes are involved in (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity?
The activity is encoded by genes such as the (R)-2-hydroxyglutarate dehydrogenase from Acidaminococcus fermentans, and in humans by L2HGDH and related dehydrogenases.
What is the reaction catalyzed by GO:0120568?
The reaction is: (R)-2-hydroxyglutarate + NAD+ = 2-oxoglutarate + NADH + H+.
Why is (R)-2-hydroxyglutarate dehydrogenase important in cancer?
It regulates levels of the oncometabolite (R)-2-hydroxyglutarate, which inhibits TET2 and KDM4A, leading to epigenetic changes and pseudohypoxia.
How is (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity measured?
It is commonly measured by monitoring NADH production at 340 nm, often coupled to aminotransferase reactions.
What is the synonym for GO:0120568?
The synonym is 2-oxoglutarate reductase activity, reflecting the reverse reaction.
What is the role of NAD+ in this enzyme activity?
NAD+ serves as the electron acceptor, accepting a hydride from (R)-2-hydroxyglutarate to form NADH.
How does acidic pH affect (R)-2-hydroxyglutarate dehydrogenase?
Acidic pH acts as a metabolic switch that promotes 2-hydroxyglutarate generation and signaling, potentially modulating enzyme flux.
Can CRISPR be used to study (R)-2-hydroxyglutarate dehydrogenase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise interrogation of this activity in cells.
What diseases are linked to (R)-2-hydroxyglutarate metabolism?
Diseases include gliomas, acute myeloid leukemia, and L-2-hydroxyglutaric aciduria, as well as chemosensitivity in DNA repair-deficient tumors.
Conclusion
GO:0120568, (R)-2-hydroxyglutarate (NAD+) dehydrogenase activity, is a stereospecific NAD+-dependent enzyme function that controls the cellular levels of the oncometabolite (R)-2-hydroxyglutarate. Its structural and mechanistic features have been elucidated, and it serves as a valuable tool for biochemical assays. Dysregulation of this activity contributes to cancer, pseudohypoxia, and DNA repair defects, making it a target for therapeutic intervention. CRISPR-based models from EDITGENE provide a robust platform to dissect the function of this enzyme in health and disease. By combining knockout, point mutation, knock-in, and overexpression strategies, researchers can uncover causal roles and identify new therapeutic opportunities.
References
- 1. Martins BM et al.. 2005. Structural basis for stereo-specific catalysis in NAD(+)-dependent (R)-2-hydroxyglutarate dehydrogenase from Acidaminococcus fermentans.. FEBS J 272(1):269-81 PMID: 15634349
- 2. Stepanenko AA et al.. 2013. Antagonistic functional duality of cancer genes.. Gene 529(2):199-207 PMID: 23933273
- 3. Ebisuno T et al.. 1975. D-alpha-Hydroxyglutarate dehydrogenase of Rhodospirillum rubrum.. J Biochem 78(6):1321-9 PMID: 5424
- 4. Yu X et al.. 2012. Development of a satisfactory and general continuous assay for aminotransferases by coupling with (R)-2-hydroxyglutarate dehydrogenase.. Anal Biochem 431(2):127-31 PMID: 23000002
- 5. Nadtochiy SM et al.. 2016. Acidic pH Is a Metabolic Switch for 2-Hydroxyglutarate Generation and Signaling.. J Biol Chem 291(38):20188-97 PMID: 27510037
- 6. Saville KM et al.. 2024. Oncometabolite 2-hydroxyglutarate suppresses basal protein levels of DNA polymerase beta that enhances alkylating agent and PARG inhibition induced cytotoxicity.. DNA Repair (Amst) 140:103700 PMID: 38897003
- 7. Menendez JA et al.. 2014. Gerometabolites: the pseudohypoxic aging side of cancer oncometabolites.. Cell Cycle 13(5):699-709 PMID: 24526120
- 8. Schweiger G et al.. 1984. On the dehydration of (R)-lactate in the fermentation of alanine to propionate by Clostridium propionicum.. FEBS Lett 171(1):79-84 PMID: 6586495
