GO:0160167 oxoadipate dehydrogenase complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0160167 (oxoadipate dehydrogenase complex, OADHC) is a mitochondrial multi-enzyme complex that catalyzes the oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA, the final step of lysine and tryptophan catabolism.
• OADHC is composed of three enzymes: E1 (2-oxoadipate dehydrogenase), E2 (dihydrolipoamide S-glutaryltransferase) and E3 (dihydrolipoamide dehydrogenase).
• The complex shares its E2 and E3 components with the 2-oxoglutarate dehydrogenase complex (OGDHC), linking lysine/tryptophan degradation to the TCA cycle.
• OADHC produces superoxide/hydrogen peroxide as a side reaction, implicating it in mitochondrial oxidative stress.
• Inhibition of OADHC causes protein glutarylation and delayed metabolic effects in the brain, suggesting a role in neuro-metabolic regulation.
• OADHC is a target for studying inborn errors of lipoic acid biosynthesis, which impair E2 function.
Description
The oxoadipate dehydrogenase complex (OADHC; GO:0160167) is a mitochondrial multi-enzyme assembly that catalyzes the oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA, the terminal step in the degradation of L-lysine, L-hydroxylysine and L-tryptophan. This complex is functionally and structurally related to the 2-oxoglutarate dehydrogenase complex (OGDHC), with which it shares the E2 and E3 subunits. Because of this shared architecture, OADHC sits at the interface of amino acid catabolism and the tricarboxylic acid (TCA) cycle, making it a key node in mitochondrial energy metabolism and redox balance. Researchers study OADHC to understand lysine/tryptophan catabolism, mitochondrial reactive oxygen species (ROS) production, and the metabolic consequences of its dysfunction in neurological and metabolic disorders. The complex is also relevant to inherited defects in lipoic acid biosynthesis, which affect the lipoyl-dependent E2 subunit. This article summarizes the composition, catalytic mechanism, regulation, disease links and experimental models for GO:0160167, based on authoritative QuickGO data and verified PubMed literature.
oxoadipate dehydrogenase complex At A Glance
| GO ID | GO:0160167 |
|---|---|
| GO term | oxoadipate dehydrogenase complex |
| Ontology | cellular_component |
| Synonym | OADHC |
| Major function | Oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA in lysine and tryptophan catabolism |
| Subunits | E1 (2-oxoadipate dehydrogenase), E2 (dihydrolipoamide S-glutaryltransferase), E3 (dihydrolipoamide dehydrogenase) |
| Subcellular location | Mitochondrion |
| Pathway context | Final step of L-lysine, L-hydroxylysine and L-tryptophan degradation |
| Related complex | Shares E2 and E3 with the 2-oxoglutarate dehydrogenase complex (OGDHC) |
What Is GO:0160167?
According to the Gene Ontology, GO:0160167 (oxoadipate dehydrogenase complex) is a multi-enzyme complex that catalyzes the oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA, thereby acting in the final step of lysine and tryptophan catabolism in mitochondria. The complex comprises multiple copies of three enzymes referred to as E1, E2 and E3: 2-oxoadipate dehydrogenase (E1), dihydrolipoamide S-glutaryltransferase (E2) and dihydrolipoamide dehydrogenase (E3).
Why Is oxoadipate dehydrogenase complex Important in Cell Biology?
OADHC is important because it catalyzes the final step of lysine and tryptophan catabolism, connecting amino acid degradation to glutaryl-CoA production and mitochondrial metabolism. Its shared E2/E3 components with OGDHC create a functional and regulatory cross-talk between the TCA cycle and lysine/tryptophan degradation pathways. The complex also generates superoxide/hydrogen peroxide as a side reaction, contributing to mitochondrial ROS and oxidative stress. Inhibition of OADHC leads to protein glutarylation and delayed metabolic changes in the brain, highlighting its role in neuro-metabolic regulation. Furthermore, OADHC function depends on lipoylation, so defects in lipoic acid biosynthesis impair its activity and cause metabolic disease. Understanding OADHC is therefore relevant to mitochondrial biology, redox signaling, and inherited metabolic disorders.
• Catalyzes the final step of L-lysine, L-hydroxylysine and L-tryptophan catabolism in mitochondria.
• Shares E2 and E3 subunits with the 2-oxoglutarate dehydrogenase complex, linking amino acid degradation to the TCA cycle.
• Produces superoxide/hydrogen peroxide, contributing to mitochondrial ROS and oxidative stress.
• Its inhibition causes protein glutarylation and delayed brain metabolic effects.
• Requires lipoic acid for E2 function; defects in lipoic acid biosynthesis impair the complex.
• Is a potential source of oxidative stress in mitochondria alongside OGDHC.
• Relevant to inborn errors of metabolism affecting lysine/tryptophan degradation.
• Provides a model for studying substrate channeling and enzyme complex assembly.
• Can use non-cognate substrates such as 2-oxopimelic acid, showing functional versatility.
• Serves as a target for understanding mitochondrial redox balance and neuro-metabolism.
Structure and Composition of oxoadipate dehydrogenase complex
Overall architecture of OADHC
In simple terms: OADHC is a molecular machine made of three different enzymes working together.
The oxoadipate dehydrogenase complex is a multi-enzyme complex comprising multiple copies of three enzymes: E1 (2-oxoadipate dehydrogenase), E2 (dihydrolipoamide S-glutaryltransferase) and E3 (dihydrolipoamide dehydrogenase). This architecture is shared with other 2-oxo acid dehydrogenase complexes, and the complex functions in the final step of lysine and tryptophan catabolism.
E1 subunit: 2-oxoadipate dehydrogenase
In simple terms: E1 is the enzyme that recognizes and starts the breakdown of 2-oxoadipate.
The E1 subunit of OADHC is 2-oxoadipate dehydrogenase, which catalyzes the oxidative decarboxylation of 2-oxoadipate. Studies have shown that human E1 can also act on non-cognate substrates such as 2-oxopimelic acid, indicating functional versatility in the lysine degradation pathway. The E1 component interacts with E2, and these interactions have been probed by chemical cross-linking mass spectrometry and molecular dynamics simulations.
E2 subunit: dihydrolipoamide S-glutaryltransferase
In simple terms: E2 is the core enzyme that transfers the glutaryl group and uses lipoic acid as a cofactor.
The E2 subunit, dihydrolipoamide S-glutaryltransferase, forms the core of the complex and requires lipoic acid for its activity. OADHC shares its E2 component with the 2-oxoglutarate dehydrogenase complex, meaning both complexes rely on the same E2 protein for function. Defects in lipoic acid biosynthesis impair E2 function and thus affect OADHC activity.
E3 subunit: dihydrolipoamide dehydrogenase
In simple terms: E3 is the enzyme that regenerates the cofactor so the complex can keep working.
The E3 subunit, dihydrolipoamide dehydrogenase, is shared between OADHC and OGDHC and is responsible for reoxidizing the lipoamide cofactor. This shared usage links the redox state of the two complexes and allows cross-talk between the TCA cycle and lysine/tryptophan degradation pathways.
Assembly and subcomplex interactions
In simple terms: The parts of OADHC must fit together properly, and researchers study how they interact.
Binary subcomplexes of E1o-E2o and E1a-E2o have been characterized by chemical cross-linking mass spectrometry and molecular dynamics simulations, revealing how the E1 and E2 components interact in human OADHC and OGDHC. These interactions are critical for assembly and catalytic efficiency, and they highlight the structural similarity between the two complexes.
Key Genes Involved in GO:0160167 oxoadipate dehydrogenase complex
The following genes and proteins are central to the composition, function and regulation of the oxoadipate dehydrogenase complex (GO:0160167).
| Gene | Major Role | Research Relevance |
|---|---|---|
| DHTKD1 | Encodes the E1 subunit (2-oxoadipate dehydrogenase) of OADHC | Mutations cause a metabolic disorder; target for studying lysine/tryptophan catabolism |
| DLST | Encodes the E2 subunit (dihydrolipoamide S-glutaryltransferase) shared with OGDHC | Central to complex assembly and lipoic acid dependence |
| DLD | Encodes the E3 subunit (dihydrolipoamide dehydrogenase) shared with OGDHC | Links redox metabolism and ROS production |
| OGDH | Encodes E1 of OGDHC, which cross-talks with OADHC | Studying shared components and regulatory cross-talk |
| LIAS | Involved in lipoic acid biosynthesis, required for E2 lipoylation | Defects impair OADHC and cause metabolic disease |
| LIPT1 | Lipoate transferase, required for lipoylation of E2 | Relevant to lipoic acid biosynthesis defects |
| LIPT2 | Lipoate transferase, involved in lipoic acid metabolism | Relevant to lipoic acid biosynthesis defects |
| NFU1 | Iron-sulfur cluster assembly, affects lipoic acid biosynthesis | Linked to multiple mitochondrial dysfunction syndromes |
| BOLA3 | Iron-sulfur cluster assembly, affects lipoic acid biosynthesis | Linked to multiple mitochondrial dysfunction syndromes |
| GCSH | Glycine cleavage system H protein, lipoylation target | Model for studying lipoic acid defects |
| PDHX | Component of pyruvate dehydrogenase complex, shares E3 | Comparative studies of 2-oxo acid dehydrogenase complexes |
| PDHB | E1 beta of pyruvate dehydrogenase complex | Comparative studies of complex assembly |
| DLAT | E2 of pyruvate dehydrogenase complex | Comparative studies of lipoyl domains |
| SOD2 | Mitochondrial superoxide dismutase, detoxifies ROS from OADHC | Studying oxidative stress from OADHC |
| CAT | Catalase, detoxifies hydrogen peroxide | Studying ROS production by OADHC |
| GPX1 | Glutathione peroxidase, detoxifies hydrogen peroxide | Studying ROS production by OADHC |
| SLC25A21 | Mitochondrial oxodicarboxylate carrier, transports 2-oxoadipate | Relevant to substrate supply for OADHC |
| AASS | Alpha-aminoadipate semialdehyde synthase, upstream in lysine degradation | Provides substrate for OADHC |
How Is oxoadipate dehydrogenase complex Regulated?
OADHC activity is regulated by substrate availability, product inhibition, and the redox state of its shared E3 component. Functional and regulatory cross-talk exists between OADHC and OGDHC, as they compete for shared E2 and E3 subunits and influence each other's activity. The complex is also regulated by the availability of lipoic acid, which is required for E2 function; defects in lipoic acid biosynthesis reduce OADHC activity. Additionally, inhibition of OADHC leads to protein glutarylation, which may feedback on metabolic pathways. ROS production by OADHC is a side reaction that can be modulated by the redox environment and may contribute to oxidative stress.
oxoadipate dehydrogenase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DHTKD1 | Metabolic disorder with impaired lysine/tryptophan catabolism | Knockout or point-mutation cell models |
| DLST | Lipoic acid biosynthesis defect affecting E2 function | Knock-in of patient mutations |
| DLD | Redox imbalance and ROS production | Overexpression or knockout models |
| LIAS | Lipoic acid biosynthesis defect | Knockout cell models |
| NFU1 | Multiple mitochondrial dysfunction syndrome | Knock-in of patient mutations |
OADHC and oxidative stress
The oxoadipate dehydrogenase complex generates superoxide/hydrogen peroxide as a side reaction during catalysis, contributing to mitochondrial ROS. Both OADHC and OGDHC produce ROS, and each could contribute to oxidative stress in mitochondria. This links OADHC to conditions involving mitochondrial oxidative damage, such as neurodegenerative diseases.
OADHC and neuro-metabolic disorders
Inhibition of OADHC in the rat brain leads to delayed metabolic effects linked to protein glutarylation, suggesting a role in neuro-metabolic regulation. This implies that OADHC dysfunction may affect brain metabolism and contribute to neurological phenotypes.
Lipoic acid biosynthesis defects and OADHC
Lipoic acid biosynthesis defects impair the lipoylation of E2 subunits, including that of OADHC, leading to metabolic disorders. These defects affect multiple mitochondrial enzyme complexes and cause severe clinical phenotypes.
OADHC in inherited metabolic diseases
Mutations in DHTKD1, encoding the E1 subunit of OADHC, cause a metabolic disorder characterized by abnormal lysine and tryptophan catabolism. The complex is therefore relevant to inborn errors of metabolism affecting these pathways.
From oxoadipate dehydrogenase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of DHTKD1 impair lysine catabolism? | DHTKD1 knockout cell line |
| Does a patient mutation in DLST affect OADHC assembly? | DLST point-mutation knock-in |
| Can wild-type DHTKD1 rescue metabolic defects? | DHTKD1 overexpression |
| Where is OADHC localized in mitochondria? | Tagged knock-in of DHTKD1 with fluorescent tag |
| Does OADHC inhibition affect protein glutarylation? | OADHC inhibitor treatment in cell models |
| What is the role of E3 in ROS production? | DLD knockout or overexpression |
How to Study the oxoadipate dehydrogenase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme activity assay | Oxidative decarboxylation of 2-oxoadipate | Measuring OADHC activity in cell lysates |
| ROS detection | Superoxide/hydrogen peroxide production | Quantifying oxidative stress from OADHC |
| Cross-linking mass spectrometry | Protein-protein interactions in subcomplexes | Studying E1-E2 assembly |
| Molecular dynamics simulation | Structural dynamics of complex components | Modeling E1-E2 interactions |
| Metabolic profiling | Levels of metabolites and glutarylation | Assessing OADHC inhibition effects |
| Proteomics | Protein glutarylation and expression changes | Linking OADHC to metabolic regulation |
| Western blot | Protein expression and lipoylation status | Validating knockout or knock-in models |
| Immunofluorescence | Subcellular localization | Confirming mitochondrial localization |
Biochemical assays for OADHC activity
OADHC activity can be measured by monitoring the oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA using spectrophotometric or fluorometric assays. These assays are used to study enzyme kinetics, substrate specificity and the effects of inhibitors.
ROS detection methods
Superoxide/hydrogen peroxide production by OADHC can be measured using fluorescent probes or electron paramagnetic resonance. These methods help quantify the contribution of OADHC to mitochondrial oxidative stress.
Cross-linking mass spectrometry and molecular dynamics
Chemical cross-linking mass spectrometry combined with molecular dynamics simulations has been used to probe E1-E2 interactions in OADHC and OGDHC. This approach reveals structural details of subcomplex assembly.
Metabolic and proteomic profiling
Metabolic profiling and proteomics can assess the impact of OADHC inhibition on protein glutarylation and brain metabolism. These methods link OADHC function to broader metabolic networks.
How CRISPR Can Be Used to Study GO:0160167 oxoadipate dehydrogenase complex
Knockout
CRISPR knockout of DHTKD1, DLST or DLD can abolish OADHC function, allowing researchers to study the consequences for lysine/tryptophan catabolism, ROS production and protein glutarylation. Knockout cell models are useful for validating the role of OADHC in metabolic pathways.
Point Mutation
Point mutations in DHTKD1 or DLST identified in patients can be introduced using CRISPR to model metabolic disorders and assess their impact on OADHC assembly and activity. These models help establish causality between specific mutations and disease phenotypes.
Knock-in
Knock-in of tagged versions of DHTKD1 or DLST enables visualization and purification of OADHC components for interaction studies. Tagged knock-in models are valuable for studying subcomplex assembly and localization.
Overexpression
Overexpression of wild-type or mutant DHTKD1, DLST or DLD can be used to study gain-of-function effects, ROS production and rescue of knockout phenotypes. Overexpression models help dissect the contribution of individual subunits to OADHC function.
How EDITGENE Supports oxoadipate dehydrogenase complex Research
Researchers studying oxoadipate dehydrogenase complex-related genes often need to determine whether a candidate gene is causally involved in lysine/tryptophan catabolism, ROS production or metabolic disease. EDITGENE provides CRISPR-based cell model services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for oxoadipate dehydrogenase complex research.
Frequently Asked Questions About oxoadipate dehydrogenase complex
What is the oxoadipate dehydrogenase complex?
The oxoadipate dehydrogenase complex (GO:0160167) is a mitochondrial multi-enzyme complex that catalyzes the oxidative decarboxylation of 2-oxoadipate to glutaryl-CoA, the final step of lysine and tryptophan catabolism.
What genes are involved in the oxoadipate dehydrogenase complex?
Key genes include DHTKD1 (E1), DLST (E2) and DLD (E3), as well as lipoic acid biosynthesis genes such as LIAS, LIPT1 and LIPT2.
What is the function of GO:0160167?
GO:0160167 functions in the final step of L-lysine, L-hydroxylysine and L-tryptophan degradation, converting 2-oxoadipate to glutaryl-CoA.
Where is the oxoadipate dehydrogenase complex located?
It is located in mitochondria.
Does the oxoadipate dehydrogenase complex produce ROS?
Yes, it generates superoxide/hydrogen peroxide as a side reaction, contributing to mitochondrial oxidative stress.
What are the subunits of OADHC?
OADHC comprises E1 (2-oxoadipate dehydrogenase), E2 (dihydrolipoamide S-glutaryltransferase) and E3 (dihydrolipoamide dehydrogenase).
How is OADHC related to OGDHC?
OADHC shares its E2 and E3 components with the 2-oxoglutarate dehydrogenase complex, creating functional cross-talk.
What diseases are linked to OADHC dysfunction?
OADHC dysfunction is linked to metabolic disorders, oxidative stress and neuro-metabolic effects.
How can I study OADHC in the lab?
You can use enzyme activity assays, ROS detection, cross-linking mass spectrometry and CRISPR knockout models.
What CRISPR models are available for OADHC research?
Knockout, point-mutation, knock-in and overexpression models for DHTKD1, DLST, DLD and related genes.
Conclusion
The oxoadipate dehydrogenase complex (GO:0160167) is a mitochondrial multi-enzyme complex essential for the final step of lysine and tryptophan catabolism. Its shared components with OGDHC, its capacity to produce ROS, and its links to metabolic and neurological disorders make it a compelling subject for mitochondrial research. CRISPR-based cell models targeting DHTKD1, DLST, DLD and related genes provide powerful tools to dissect OADHC function and disease mechanisms.
References
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- 2. Nemeria NS et al.. 2018. Evidence for functional and regulatory cross-talk between the tricarboxylic acid cycle 2-oxoglutarate dehydrogenase complex and 2-oxoadipate dehydrogenase on the l-lysine, l-hydroxylysine and l-tryptophan degradation pathways from studies in vitro.. Biochim Biophys Acta Bioenerg 1859(9):932-939 PMID: 29752936
- 3. Jordan F et al.. 2019. Human 2-Oxoglutarate Dehydrogenase and 2-Oxoadipate Dehydrogenase Both Generate Superoxide/H(2)O(2) in a Side Reaction and Each Could Contribute to Oxidative Stress in Mitochondria.. Neurochem Res 44(10):2325-2335 PMID: 30847859
- 4. Mayr JA et al.. 2014. Lipoic acid biosynthesis defects.. J Inherit Metab Dis 37(4):553-63 PMID: 24777537
- 5. Nemeria NS et al.. 2022. Functional Versatility of the Human 2-Oxoadipate Dehydrogenase in the L-Lysine Degradation Pathway toward Its Non-Cognate Substrate 2-Oxopimelic Acid.. Int J Mol Sci 23(15) PMID: 35897808
- 6. Ozohanics O et al.. 2023. Probing the E1o-E2o and E1a-E2o Interactions in Binary Subcomplexes of the Human 2-Oxoglutarate Dehydrogenase and 2-Oxoadipate Dehydrogenase Complexes by Chemical Cross-Linking Mass Spectrometry and Molecular Dynamics Simulation.. Int J Mol Sci 24(5) PMID: 36901986
- 7. Boyko AI et al.. 2022. Delayed Impact of 2-Oxoadipate Dehydrogenase Inhibition on the Rat Brain Metabolism Is Linked to Protein Glutarylation.. Front Med (Lausanne) 9:896263 PMID: 35721081
- 8. Nemeria NS et al.. 2018. The mitochondrial 2-oxoadipate and 2-oxoglutarate dehydrogenase complexes share their E2 and E3 components for their function and both generate reactive oxygen species.. Free Radic Biol Med 115:136-145 PMID: 29191460
