GO:0008718 D-amino-acid dehydrogenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008718 describes D-amino-acid dehydrogenase activity, a quinone-dependent oxidoreductase reaction that converts a D-alpha-amino acid plus a quinone and water into a 2-oxocarboxylate, a quinol, and ammonium.
• The reaction is a deaminating oxidation, meaning the amino group of the D-amino acid is released as ammonium while the carbon skeleton becomes a 2-oxocarboxylate.
• D-amino-acid dehydrogenase from Helicobacter pylori NCTC 11637 has been biochemically characterized and uses quinone electron acceptors.
• D-amino-acid dehydrogenase activity is distinct from D-amino acid oxidase activity, which uses molecular oxygen and produces hydrogen peroxide rather than ammonium and a quinol.
• Enzyme engineering and immobilization studies show that D-amino-acid dehydrogenases can be repurposed for synthesis of D-phenylalanine and other D-amino acids.
• D-amino acid metabolism is relevant to brain function, aging, neurodegeneration, and gut microbiota, making this activity a target for mechanistic and translational studies [5,6,8].
Description
D-amino-acid dehydrogenase activity (GO:0008718) is a molecular function defined by the catalysis of the reaction: a D-alpha-amino acid + a quinone + H2O = a 2-oxocarboxylate + a quinol + NH4+. This reaction sits at the intersection of D-amino acid catabolism and quinone-dependent respiratory or redox metabolism, and it is mechanistically distinct from the better-known flavoenzyme D-amino acid oxidase, which uses oxygen and generates hydrogen peroxide. Because D-amino acids are now recognized as biologically active molecules in bacteria, brain, and peripheral tissues, enzymes that consume them are of growing interest [5,6]. The D-amino-acid dehydrogenase from Helicobacter pylori NCTC 11637 was purified and characterized as a quinone-dependent enzyme, providing a direct biochemical anchor for GO:0008718. More recent work has explored site-specific immobilization of a D-amino acid dehydrogenase for the synthesis of D-phenylalanine, showing that this activity can be harnessed for biocatalysis. Researchers study GO:0008718 to understand D-amino acid homeostasis, to engineer enzymes for chiral amine synthesis, and to probe links between D-amino acid metabolism and host physiology [1,3,8].
D-amino-acid dehydrogenase activity At A Glance
| GO ID | GO:0008718 |
|---|---|
| GO term | D-amino-acid dehydrogenase activity |
| Ontology | molecular_function |
| Synonym | D-amino-acid:(acceptor) oxidoreductase (deaminating); D-amino-acid:acceptor oxidoreductase (deaminating) |
| Major function | Oxidative deamination of D-alpha-amino acids using a quinone electron acceptor, producing a 2-oxocarboxylate, a quinol, and ammonium |
| Reaction direction | D-alpha-amino acid + a quinone + H2O = a 2-oxocarboxylate + a quinol + NH4+ |
| Electron acceptor | Quinone (not molecular oxygen), distinguishing it from D-amino acid oxidase [2,3] |
| Representative enzyme source | Helicobacter pylori NCTC 11637 D-amino acid dehydrogenase |
| Biotechnological relevance | Site-specifically immobilized D-amino acid dehydrogenase for synthesis of D-phenylalanine |
What Is GO:0008718?
In plain terms, GO:0008718 describes an enzyme activity that removes an amino group from a D-alpha-amino acid while transferring electrons to a quinone. The official QuickGO definition states: Catalysis of the reaction: a D-alpha-amino acid + a quinone + H2O = a 2-oxocarboxylate + a quinol + NH4+. This means the substrate is a D-configured alpha-amino acid, the electron acceptor is a quinone, water is consumed, and the products are a 2-oxocarboxylate, a reduced quinol, and ammonium. The synonym D-amino-acid:(acceptor) oxidoreductase (deaminating) emphasizes that the reaction is an oxidoreductase reaction in which the acceptor is not oxygen but a quinone or related acceptor.
Why Is D-amino-acid dehydrogenase activity Important in Cell Biology?
GO:0008718 matters because it defines a specific route for D-amino acid breakdown that is chemically and physiologically distinct from D-amino acid oxidase. D-amino acids are not merely metabolic curiosities; they participate in bacterial cell wall metabolism, host-microbe interactions, and neurotransmission, and their levels are influenced by enzymes that degrade them [5,6,8]. The quinone-dependent dehydrogenase reaction links D-amino acid catabolism to respiratory electron transport chains and redox balance, which is relevant for pathogens such as Helicobacter pylori. In biotechnology, D-amino-acid dehydrogenases are attractive catalysts for producing enantiopure D-amino acids, as shown by immobilization strategies for D-phenylalanine synthesis. Finally, because D-amino acid metabolism intersects with aging and neurodegeneration, understanding GO:0008718 supports research into how D-amino acid pools are maintained in the brain and periphery [5,6].
• Provides a quinone-dependent route for D-amino acid deamination, distinct from flavin-dependent D-amino acid oxidase [2,3].
• Supports D-amino acid catabolism in bacteria such as Helicobacter pylori, where the enzyme has been biochemically characterized.
• Enables biocatalytic production of D-amino acids, including D-phenylalanine, through enzyme immobilization.
• Connects D-amino acid metabolism to quinone pools and respiratory electron transport, influencing cellular redox state.
• Relevant to brain D-amino acid homeostasis, because D-amino acid degrading enzymes shape D-serine and related pools.
• Relevant to aging and neurodegeneration research, where D-amino acid oxidase activity changes with age and sex.
• Relevant to gut microbiota and antimicrobial peptide biology through D-amino acid oxidase-derived peptides.
• Provides a target for enzyme engineering to alter substrate specificity or electron acceptor preference.
• Offers a molecular function anchor for annotating genomes and metagenomes with D-amino acid catabolic potential.
• Complements D-amino acid oxidase research, allowing researchers to dissect parallel D-amino acid degradation pathways [2,4].
What Happens During D-amino-acid dehydrogenase activity?
Substrate recognition of D-alpha-amino acids
In simple terms: The enzyme first binds a D-amino acid, the mirror-image form of a standard amino acid.
The reaction begins with binding of a D-alpha-amino acid substrate. The enzyme must discriminate D-configured amino acids from L-configured amino acids, because the dehydrogenase reaction is defined for D-alpha-amino acids. The Helicobacter pylori D-amino acid dehydrogenase was characterized with D-amino acid substrates, establishing that the enzyme operates on D-configured amino acids. This substrate selectivity is a key feature that distinguishes GO:0008718 from L-amino acid dehydrogenases and from D-amino acid oxidase, which also acts on D-amino acids but uses oxygen [2,3].
Quinone-dependent oxidation and deamination
In simple terms: The enzyme removes electrons from the D-amino acid and hands them to a quinone molecule.
In the catalytic step, the D-alpha-amino acid is oxidized and deaminated. The QuickGO definition specifies that a quinone is the electron acceptor and that water participates in the reaction, yielding a 2-oxocarboxylate, a quinol, and ammonium. This is an oxidoreductase reaction in which the acceptor is a quinone rather than molecular oxygen, which is why the synonym includes acceptor oxidoreductase deaminating. The formation of ammonium reflects the removal of the amino group, while the 2-oxocarboxylate is the carbon skeleton of the original D-amino acid.
Product formation and redox coupling
In simple terms: The reaction produces a keto acid, a reduced quinone, and ammonium.
The products of GO:0008718 are a 2-oxocarboxylate, a quinol, and NH4+. The quinol product links this activity to quinone pools, which are central to respiratory and redox metabolism. Because the reaction consumes a quinone and produces a quinol, the activity is intrinsically coupled to the redox state of the cell or organelle where it occurs. This coupling distinguishes it from D-amino acid oxidase, which produces hydrogen peroxide and does not generate ammonium.
Physiological context of D-amino acid turnover
In simple terms: By breaking down D-amino acids, this activity helps control how much D-amino acid is available in cells and tissues.
D-amino acids are present in bacteria, brain, and peripheral tissues, and their levels are regulated by degrading enzymes [5,6]. D-amino acid oxidase is a well-studied D-amino acid degrading enzyme, and its activity changes with age and sex in mouse brain and peripheral tissues, with implications for aging and neurodegeneration. Mutant rodents lacking D-amino acid oxidase activity have been used to study D-amino acid levels in the brain, showing that D-amino acid degradation pathways shape brain D-amino acid pools. GO:0008718 represents a parallel, quinone-dependent route for D-amino acid turnover that can contribute to these pools.
Key Genes Involved in GO:0008718 D-amino-acid dehydrogenase activity
The table below lists genes and proteins that are experimentally or mechanistically connected to D-amino acid dehydrogenase activity (GO:0008718) and to the broader D-amino acid metabolic network, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| D-amino acid dehydrogenase (H. pylori NCTC 11637 enzyme) | Catalyzes quinone-dependent oxidative deamination of D-amino acids | Biochemical characterization of GO:0008718 activity |
| D-amino acid dehydrogenase (immobilized enzyme for D-phenylalanine synthesis) | Biocatalytic production of D-phenylalanine | Enzyme immobilization and industrial biocatalysis |
| D-amino acid oxidase (DAO) | Flavin-dependent oxidation of D-amino acids using oxygen | Comparison with dehydrogenase activity and D-amino acid catabolism |
| D-amino acid oxidase (DAO) in mouse brain | Age- and sex-dependent D-amino acid degradation | Aging and neurodegeneration research |
| D-amino acid oxidase (DAO) mutant rodent models | Loss of D-amino acid oxidase activity alters brain D-amino acids | In vivo D-amino acid metabolism studies |
| Human D-amino acid oxidase G183R variant | Inactive variant of human D-amino acid oxidase | Structure-function and variant analysis |
| D-amino acid oxidase-derived peptides | Antimicrobial peptides that shape gut microbiota | Microbiome and host-microbe interaction research |
| D-kynurenine derivative substrates | Fluorescence probes for D-amino acid oxidase activity | Activity assays and screening |
| Quinone pool components | Electron acceptors for D-amino-acid dehydrogenase | Redox coupling and respiratory metabolism |
| 2-oxocarboxylate products | Metabolic products of D-amino acid deamination | Metabolic flux and keto acid analysis |
| Ammonium (NH4+) | Nitrogen product of deamination | Nitrogen metabolism and enzyme assays |
| D-phenylalanine | Product of D-amino acid dehydrogenase biocatalysis | Chiral amine synthesis |
| D-serine | Brain D-amino acid influenced by degrading enzymes | Neurotransmission and neurodegeneration research |
| D-amino acid metabolic network enzymes | Collective D-amino acid homeostasis | Comparative studies of oxidase versus dehydrogenase routes [2,3] |
| Gut microbiota D-amino acid metabolism genes | Microbial D-amino acid turnover | Microbiome and antimicrobial peptide research |
How Is D-amino-acid dehydrogenase activity Regulated?
Regulation of D-amino-acid dehydrogenase activity is not fully defined in the verified literature, but several contextual factors are relevant. The reaction depends on quinone availability, because quinones are the electron acceptors in the GO:0008718 definition. D-amino acid availability also influences flux through this activity, and D-amino acid pools are shaped by other enzymes such as D-amino acid oxidase, whose activity varies with age and sex in mouse tissues. In the brain, D-amino acid levels are affected by D-amino acid oxidase activity, as shown in mutant rodents lacking the enzyme. Human D-amino acid oxidase variants, such as the inactive G183R variant, illustrate how sequence changes can abolish D-amino acid degrading activity, providing a paradigm for studying regulation by protein variants. Finally, D-amino acid oxidase-derived peptides can influence gut microbiota, indicating that D-amino acid metabolism is embedded in host-microbe regulatory networks.
D-amino-acid dehydrogenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| D-amino acid oxidase (DAO) | Aging and neurodegeneration | DAO knockout or point-mutation cell models [5,6] |
| Human DAO G183R variant | Loss of D-amino acid degrading activity | Knock-in of G183R variant |
| D-amino acid dehydrogenase (H. pylori) | Bacterial D-amino acid catabolism and infection biology | Bacterial knockout of the dehydrogenase gene |
| D-amino acid oxidase-derived peptides | Gut microbiota composition | Microbiota colonization models |
| D-amino acid dehydrogenase (immobilized) | Biocatalytic D-phenylalanine production | Enzyme immobilization and overexpression systems |
Neurodegeneration and aging
D-amino acid metabolism has been linked to aging and neurodegeneration. D-amino acid oxidase activity in mouse brain and peripheral tissues changes with age and sex, which has implications for aging and neurodegeneration. Mutant rodents lacking D-amino acid oxidase activity have been used to study D-amino acids in the brain, showing that D-amino acid degradation influences brain D-amino acid levels. Because GO:0008718 provides an alternative quinone-dependent route for D-amino acid breakdown, it may contribute to D-amino acid homeostasis in contexts where D-amino acid oxidase is altered [3,5].
Gut microbiota and host-microbe interactions
D-amino acid oxidase-derived peptides can specify gut microbiota, indicating that D-amino acid metabolism shapes microbial communities. This connects D-amino acid degrading activities, including GO:0008718, to host-microbe interactions and antimicrobial defense. The ability of D-amino acid metabolic enzymes to influence microbiota composition makes them relevant to studies of intestinal health and infection.
Enzyme variants and metabolic disease
The human D-amino acid oxidase G183R variant is inactive, demonstrating that single amino acid changes can abolish D-amino acid degrading activity. Such variants provide models for understanding how loss of D-amino acid metabolism affects cellular and organismal physiology. Although the verified literature does not directly link GO:0008718 to a specific human disease, the broader D-amino acid metabolic network is clearly relevant to neurological and metabolic phenotypes [5,6,7].
From D-amino-acid dehydrogenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of D-amino-acid dehydrogenase activity alter D-amino acid pools? | Knockout cell model |
| Does a specific active-site residue control quinone-dependent deamination? | Point-mutation knock-in |
| Can a tagged enzyme be used to monitor localization and interactions? | Tagged knock-in |
| Does overexpression increase D-amino acid catabolic flux? | Overexpression cell model |
| Can the enzyme be engineered for D-phenylalanine synthesis? | Site-specific immobilization and overexpression |
| How does D-amino acid oxidase loss affect brain D-amino acids? | DAO mutant rodent models |
How to Study the D-amino-acid dehydrogenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzymatic activity assay | Quinone-dependent deamination of D-amino acids | Characterizing GO:0008718 activity |
| Fluorescence probe assay | D-amino acid oxidase activity using D-kynurenine derivative | Activity screening |
| Enzyme immobilization | Biocatalytic synthesis of D-phenylalanine | Industrial biocatalysis |
| Mutant rodent models | Brain D-amino acid levels after loss of D-amino acid oxidase | In vivo D-amino acid metabolism |
| Variant expression | Activity of human D-amino acid oxidase G183R | Structure-function studies |
| Microbiome analysis | Gut microbiota composition influenced by D-amino acid oxidase-derived peptides | Host-microbe interaction research |
| Age- and sex-dependent profiling | D-amino acid oxidase activity across tissues | Aging and neurodegeneration research |
| Biochemical purification | Substrate and acceptor specificity of D-amino acid dehydrogenase | Enzyme characterization |
Enzymatic activity assays
D-amino-acid dehydrogenase activity can be measured by monitoring the conversion of D-amino acid substrates to 2-oxocarboxylate, ammonium, and quinol products. Because the reaction uses a quinone acceptor, assays can be designed to track quinone reduction or product formation. For D-amino acid oxidase, fluorescence evaluation using a synthetic D-kynurenine derivative has been developed, illustrating how activity assays can be adapted for D-amino acid degrading enzymes.
Biochemical characterization and immobilization
Purification and biochemical characterization of D-amino acid dehydrogenase from Helicobacter pylori NCTC 11637 established its substrate and acceptor properties. Site-specific immobilization of a D-amino acid dehydrogenase has been used for the synthesis of D-phenylalanine, demonstrating that immobilization can support biocatalytic applications. These approaches allow researchers to determine kinetic parameters and operational stability [1,3].
Genetic and mutant models
Mutant rodents lacking D-amino acid oxidase activity have been used to study D-amino acids in the brain, providing a model for how loss of a D-amino acid degrading enzyme affects physiology. Human D-amino acid oxidase variants, such as G183R, can be expressed to study structure-function relationships. Similar knockout, point-mutation, and knock-in strategies can be applied to D-amino-acid dehydrogenase genes to test function.
Microbiome and peptide studies
D-amino acid oxidase-derived peptides have been shown to specify gut microbiota, indicating that D-amino acid metabolism can be studied in microbiome contexts. Age- and gender-dependent D-amino acid oxidase activity in mouse brain and peripheral tissues provides a framework for studying how D-amino acid degrading activities vary across conditions. These methods can be adapted to investigate GO:0008718 in host-microbe systems [5,8].
How CRISPR Can Be Used to Study GO:0008718 D-amino-acid dehydrogenase activity
Knockout
CRISPR knockout of a candidate D-amino-acid dehydrogenase gene can test whether the enzyme is required for D-amino acid catabolism in a given cell type. Loss-of-function models are useful for comparing dehydrogenase-dependent and oxidase-dependent D-amino acid degradation [2,3]. Knockout of D-amino acid oxidase has been modeled in rodents, providing a precedent for genetic loss-of-function studies in D-amino acid metabolism.
Point Mutation
Point mutations can be introduced into the active site of a D-amino-acid dehydrogenase to test catalytic residues and substrate specificity. The human D-amino acid oxidase G183R variant shows how a single mutation can inactivate a D-amino acid degrading enzyme, illustrating the value of point-mutation models. Such models help assign function to specific residues within GO:0008718 enzymes [3,7].
Knock-in
Knock-in of tagged or variant D-amino-acid dehydrogenase alleles allows localization and interaction studies. Knock-in of disease-associated or activity-altering variants, such as the DAO G183R variant, can reveal consequences for D-amino acid metabolism. These models are valuable for linking sequence variation to enzyme function.
Overexpression
Overexpression of D-amino-acid dehydrogenase can increase flux through the quinone-dependent deamination pathway and support biocatalytic applications. Site-specific immobilization of overexpressed enzyme has been used for D-phenylalanine synthesis, showing the practical value of overexpression systems. Overexpression also enables biochemical purification and kinetic analysis [1,3].
How EDITGENE Supports D-amino-acid dehydrogenase activity Research
Researchers studying D-amino-acid dehydrogenase activity-related genes often need to determine whether a candidate gene is causally involved in D-amino acid metabolism, whether a specific residue controls catalysis, or whether altering expression changes metabolic flux. CRISPR-based models provide a direct way to test these questions in relevant cell types, and EDITGENE offers a suite of services to support such studies.
Contact EDITGENE today to design your custom CRISPR model for D-amino-acid dehydrogenase activity research.
Frequently Asked Questions About D-amino-acid dehydrogenase activity
What is D-amino-acid dehydrogenase activity?
D-amino-acid dehydrogenase activity (GO:0008718) is a molecular function that catalyzes the reaction: a D-alpha-amino acid + a quinone + H2O = a 2-oxocarboxylate + a quinol + NH4+.
What is the GO ID for D-amino-acid dehydrogenase activity?
The GO ID is GO:0008718, with the official name D-amino-acid dehydrogenase activity.
What genes are involved in D-amino-acid dehydrogenase activity?
The best-characterized enzyme is the D-amino acid dehydrogenase from Helicobacter pylori NCTC 11637, and related D-amino acid metabolic genes include D-amino acid oxidase and its variants [3,7].
How is D-amino-acid dehydrogenase different from D-amino acid oxidase?
D-amino-acid dehydrogenase uses a quinone acceptor and produces ammonium and a quinol, whereas D-amino acid oxidase uses oxygen and produces hydrogen peroxide [2,3].
What reaction does GO:0008718 catalyze?
It catalyzes the oxidative deamination of a D-alpha-amino acid using a quinone and water to produce a 2-oxocarboxylate, a quinol, and ammonium.
Why is D-amino-acid dehydrogenase important for biotechnology?
It can be used for the synthesis of D-amino acids such as D-phenylalanine, especially when site-specifically immobilized.
Is D-amino-acid dehydrogenase related to brain function?
D-amino acid metabolism is relevant to brain function, and D-amino acid oxidase activity changes with age and sex in mouse brain, with implications for neurodegeneration [5,6].
What diseases are linked to D-amino acid metabolism?
D-amino acid metabolism has been linked to aging, neurodegeneration, and gut microbiota interactions, and human D-amino acid oxidase variants can abolish activity [5,6,7,8].
How can I study D-amino-acid dehydrogenase activity in the lab?
You can use enzymatic activity assays, enzyme purification, mutant models, and CRISPR knockout or knock-in cell models to study this activity [1,3,6].
What CRISPR models are available for D-amino-acid dehydrogenase research?
Knockout, point-mutation, knock-in, and overexpression models can be generated to test the function of D-amino-acid dehydrogenase genes and variants [1,3,7].
Conclusion
GO:0008718 D-amino-acid dehydrogenase activity defines a quinone-dependent, deaminating oxidation of D-alpha-amino acids that is mechanistically distinct from D-amino acid oxidase [2,3]. The reaction produces a 2-oxocarboxylate, a quinol, and ammonium, linking D-amino acid catabolism to quinone redox pools. D-amino acid metabolism is relevant to brain function, aging, neurodegeneration, and gut microbiota, and enzymes in this network are attractive targets for both mechanistic and applied research [5,6,8]. Biocatalytic applications, such as immobilized D-amino-acid dehydrogenase for D-phenylalanine synthesis, further highlight the practical value of this activity. CRISPR-based knockout, point-mutation, knock-in, and overexpression models provide powerful tools to dissect the function of D-amino-acid dehydrogenase genes and their variants [1,3,7].
References
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- 2. Pilone MS. 2000. D-Amino acid oxidase: new findings.. Cell Mol Life Sci 57(12):1732-47 PMID: 11130179
- 3. Tanigawa M et al.. 2010. D-Amino acid dehydrogenase from Helicobacter pylori NCTC 11637.. Amino Acids 38(1):247-55 PMID: 19212808
- 4. Sakamoto T et al.. 2022. Direct Fluorescence Evaluation of d-Amino Acid Oxidase Activity Using a Synthetic d-Kynurenine Derivative.. Anal Chem 94(42):14530-14536 PMID: 36222234
- 5. Kim SH et al.. 2019. Age- and gender-dependent D-amino acid oxidase activity in mouse brain and peripheral tissues: implication for aging and neurodegeneration.. J Biochem 166(2):187-196 PMID: 30938755
- 6. Yamanaka M et al.. 2012. D-Amino acids in the brain and mutant rodents lacking D-amino-acid oxidase activity.. Amino Acids 43(5):1811-21 PMID: 22892863
- 7. Murtas G et al.. 2018. Human d-amino acid oxidase: The inactive G183R variant.. Biochim Biophys Acta Proteins Proteom 1866(7):822-830 PMID: 29274788
- 8. Murtas G et al.. 2021. Antimicrobial D-amino acid oxidase-derived peptides specify gut microbiota.. Cell Mol Life Sci 78(7):3607-3620 PMID: 33484270
