GO:0110050 deaminated glutathione amidase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0110050 deaminated glutathione amidase activity is a molecular_function defined as the hydrolysis of N-(4-oxoglutarate)-L-cysteinylglycine to 2-oxoglutarate and L-cysteinylglycine.
• The activity is a metabolite repair function that removes a spontaneously formed deaminated glutathione adduct, preventing loss of glutathione and accumulation of a damaged metabolite.
• Nit1 is the principal enzyme in mammals that carries this activity, and it belongs to the nitrilase superfamily, a large group of amidases and related enzymes.
• The reaction is part of the transaminase-omega-amidase pathway that links glutathione turnover to glutamine metabolism and alpha-ketoglutarate levels, and it responds to oxidative stress in endothelial cells.
• Loss of deaminated glutathione amidase activity can disturb cellular redox balance and metabolite pools, which is relevant to cancer, metabolic stress, and endothelial dysfunction.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are the main tools for testing the causal role of this activity in cells and organisms.
Description
GO:0110050 deaminated glutathione amidase activity is a molecular_function term that describes a specific hydrolytic reaction: N-(4-oxoglutarate)-L-cysteinylglycine + H2O = 2-oxoglutarate + L-cysteinylglycine. This activity is unusual because its substrate is not a standard metabolite but a damaged adduct formed when glutathione reacts with a reactive carbonyl species, and its product is a free amino acid derivative plus a central metabolic intermediate. The term therefore sits at the intersection of glutathione homeostasis, metabolite repair, and alpha-ketoglutarate metabolism. Researchers care about this activity because it protects cells from the consequences of spontaneous metabolite damage. Without repair, deaminated glutathione would accumulate and glutathione would be sequestered in a form that cannot perform its antioxidant and redox-buffering roles. The enzyme that carries this activity, Nit1, is a member of the nitrilase superfamily, a large and ancient group of enzymes whose catalytic chemistry has been studied for decades. Understanding GO:0110050 therefore connects basic enzymology to cellular stress responses and to disease states in which redox and glutamine metabolism are perturbed. This article summarizes the authoritative definition, the catalytic and structural context, the genes and pathways involved, and the experimental methods used to study deaminated glutathione amidase activity. It is written for researchers who need a precise, citation-backed overview that can support experimental design, grant writing, and target evaluation.
deaminated glutathione amidase activity At A Glance
| GO ID | GO:0110050 |
|---|---|
| GO term | deaminated glutathione amidase activity |
| Ontology | molecular_function |
| Synonym | none |
| Definition | Catalysis of the reaction: N-(4-oxoglutarate)-L-cysteinylglycine + H2O = 2-oxoglutarate + L-cysteinylglycine |
| Major function | Metabolite repair by hydrolyzing a deaminated glutathione adduct to release 2-oxoglutarate and L-cysteinylglycine |
| Representative enzyme | Nit1, a nitrilase superfamily amidase |
| Pathway context | Transaminase-omega-amidase pathway linking glutathione turnover to glutamine metabolism and alpha-ketoglutarate levels |
| Substrate | N-(4-oxoglutarate)-L-cysteinylglycine |
| Products | 2-oxoglutarate and L-cysteinylglycine |
What Is GO:0110050?
In simple terms, GO:0110050 deaminated glutathione amidase activity is the ability of an enzyme to cut a damaged glutathione molecule and release two useful pieces. More formally, it catalyzes the reaction N-(4-oxoglutarate)-L-cysteinylglycine + H2O = 2-oxoglutarate + L-cysteinylglycine. The substrate is a deaminated glutathione adduct in which the cysteine moiety has been converted to a 4-oxoglutarate-linked form, and the enzyme hydrolyzes the amide bond to release 2-oxoglutarate and L-cysteinylglycine. This is a metabolite repair reaction rather than a biosynthetic step, because it recovers usable metabolites from a spontaneously damaged molecule. The activity is classified as a molecular_function, meaning it describes what the enzyme does at the chemical level rather than where it acts or which pathway it belongs to.
Why Is deaminated glutathione amidase activity Important in Cell Biology?
Deaminated glutathione amidase activity matters because it protects a central antioxidant and a central metabolic intermediate from being lost to spontaneous damage. Glutathione is the most abundant non-enzymatic antioxidant in cells, and its reaction with reactive carbonyl species can generate deaminated adducts that would otherwise accumulate. By hydrolyzing these adducts, the enzyme recovers L-cysteinylglycine and releases 2-oxoglutarate, a key intermediate in the tricarboxylic acid cycle and a co-substrate for many transamination reactions. This repair function is especially important under oxidative stress, when adduct formation increases and when cells must rapidly adjust glutamine metabolism and alpha-ketoglutarate levels. Consequently, the activity is relevant to cancer metabolism, endothelial dysfunction, and any condition in which redox balance and metabolite repair are compromised.
• Maintains glutathione availability by removing a damaged glutathione adduct that would otherwise sequester cysteine and glycine.
• Supplies 2-oxoglutarate, a central TCA cycle intermediate and nitrogen acceptor, from a repair reaction.
• Connects glutathione turnover to glutamine metabolism through the transaminase-omega-amidase pathway.
• Acts as a metabolite repair enzyme, a growing class of activities that counteract spontaneous chemical damage.
• Is carried out by Nit1, a nitrilase superfamily member whose catalytic mechanism is broadly conserved.
• Responds to oxidative stress in endothelial cells, linking the activity to vascular biology.
• Provides a potential target for modulating redox and metabolic stress in cancer and metabolic disease.
• Offers a defined enzymatic readout for CRISPR screens and biochemical assays.
• Helps interpret metabolomic signatures in which deaminated glutathione or 2-oxoglutarate levels are altered.
• Is relevant to biotechnology because amidases and nitrilases are widely used in biocatalysis.
Molecular Mechanism of deaminated glutathione amidase activity
Substrate recognition and binding
In simple terms: The enzyme first grabs the damaged glutathione molecule in a way that positions the bond to be cut.
The substrate of GO:0110050 is N-(4-oxoglutarate)-L-cysteinylglycine, a deaminated glutathione adduct in which the cysteine amino group has been converted to a 4-oxoglutarate-linked moiety. The enzyme must recognize this modified glutathione structure and bind it so that the amide bond between the 4-oxoglutarate moiety and the cysteinylglycine portion is exposed to the catalytic site. This specificity distinguishes the activity from general amidases and from other nitrilase superfamily members that act on different substrates.
Catalytic hydrolysis
In simple terms: The enzyme uses water to split the damaged molecule into two useful pieces.
The catalytic reaction is a hydrolysis: N-(4-oxoglutarate)-L-cysteinylglycine + H2O = 2-oxoglutarate + L-cysteinylglycine. The enzyme therefore functions as an amidase, cleaving a carbon-nitrogen bond with water as the nucleophile. Nit1, the principal mammalian enzyme with this activity, belongs to the nitrilase superfamily, whose members share a conserved catalytic fold and use a cysteine or serine nucleophile in a similar mechanism. The reaction releases 2-oxoglutarate, a TCA cycle intermediate, and L-cysteinylglycine, a dipeptide that can be further metabolized.
Metabolite repair function
In simple terms: This is a repair job: the enzyme fixes a molecule that was accidentally damaged.
Deaminated glutathione forms spontaneously when glutathione reacts with reactive carbonyl species, and if it is not repaired it accumulates as a damaged metabolite. Nit1 was identified as a metabolite repair enzyme that hydrolyzes deaminated glutathione, preventing the loss of glutathione and the buildup of a non-functional adduct. This repair function is distinct from biosynthetic or degradative pathways and represents a quality-control mechanism for cellular metabolites.
Link to glutamine metabolism and alpha-ketoglutarate
In simple terms: The repair reaction feeds into the cell's central carbon and nitrogen metabolism.
The transaminase-omega-amidase pathway senses oxidative stress to control glutamine metabolism and alpha-ketoglutarate levels in endothelial cells. Deaminated glutathione amidase activity produces 2-oxoglutarate, which is a key node in this pathway and a co-substrate for transamination reactions. This connects the repair of a damaged glutathione adduct to the broader regulation of glutamine utilization and TCA cycle flux.
Enzyme family and evolutionary context
In simple terms: The enzyme belongs to a large family of similar enzymes found across life.
Nit1 is a member of the nitrilase superfamily, a large group of enzymes that includes nitrilases, amidases, and related proteins. Catalysis in this superfamily has been studied extensively, and the mechanisms are broadly conserved. Amidase activity is also widespread among bacteria and has been characterized for biotechnological applications. The deaminated glutathione amidase activity of Nit1 is therefore a specialized member of a much larger catalytic family.
Key Genes Involved in GO:0110050 deaminated glutathione amidase activity
The genes and proteins most directly associated with GO:0110050 include the enzyme that carries the activity, its substrate-generating and product-utilizing partners, and related family members.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NIT1 | Principal mammalian enzyme with deaminated glutathione amidase activity; hydrolyzes deaminated glutathione | Core target for knockout, point-mutation, and overexpression studies of GO:0110050 |
| NIT2 | Nitrilase superfamily member related to NIT1; omega-amidase activity in the transaminase-omega-amidase pathway | Comparator for substrate specificity and pathway context |
| GGT1 | Gamma-glutamyltransferase involved in glutathione metabolism and cysteinylglycine handling | Upstream context for substrate availability |
| GGT5 | Gamma-glutamyltransferase family member with roles in glutathione and cysteinylglycine metabolism | Potential modifier of deaminated glutathione levels |
| GCLC | Catalytic subunit of glutamate-cysteine ligase, rate-limiting for glutathione synthesis | Determines glutathione pool size and adduct formation |
| GCLM | Modulatory subunit of glutamate-cysteine ligase | Modifies glutathione synthesis capacity |
| GSS | Glutathione synthetase, produces glutathione from gamma-glutamylcysteine | Affects substrate supply for deaminated glutathione formation |
| GLS | Glutaminase, converts glutamine to glutamate | Links glutamine metabolism to the transaminase-omega-amidase pathway |
| GLUD1 | Glutamate dehydrogenase, produces alpha-ketoglutarate from glutamate | Connects the pathway to TCA cycle and alpha-ketoglutarate levels |
| GPT | Alanine aminotransferase, a transaminase in the pathway | Transaminase-omega-amidase pathway component |
| GOT1 | Aspartate aminotransferase, a transaminase in the pathway | Transaminase-omega-amidase pathway component |
| NIT1 paralogs | Nitrilase superfamily members with related amidase chemistry | Evolutionary and mechanistic comparisons |
| Bacterial amidases | Microbial enzymes with amidase activity used in biocatalysis | Biotechnological and comparative enzymology |
| Nitrilases | Enzymes in the nitrilase superfamily with catalytic promiscuity | Mechanistic and engineering studies |
| Cysteine conjugate beta-lyases | Enzymes that process cysteinylglycine and related conjugates | Downstream metabolism of the L-cysteinylglycine product |
| Aminopeptidases | Peptidases that can further hydrolyze cysteinylglycine | Product fate and metabolite channeling |
| Transaminases | Enzymes that interconvert amino acids and alpha-keto acids | Supply and consume 2-oxoglutarate in the pathway |
| Omega-amidase | Enzyme that hydrolyzes omega-amides in the transaminase-omega-amidase pathway | Pathway partner for nitrogen disposal |
How Is deaminated glutathione amidase activity Regulated?
The transaminase-omega-amidase pathway, which includes deaminated glutathione amidase activity, senses oxidative stress to control glutamine metabolism and alpha-ketoglutarate levels in endothelial cells. This implies that the activity is not constitutive but is integrated into stress-responsive metabolic regulation. At the enzyme level, Nit1 abundance and activity determine the capacity for deaminated glutathione repair, and changes in glutathione synthesis or adduct formation will alter flux through the reaction. The pathway context also links the activity to transaminase reactions that consume or produce 2-oxoglutarate, so the net rate depends on the balance of transamination and hydrolysis. No specific transcription factor or post-translational modification has been verified for GO:0110050 in the provided citations, so regulation is best described at the pathway and metabolite level.
deaminated glutathione amidase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NIT1 | Metabolite repair deficiency; glutathione and 2-oxoglutarate imbalance | NIT1 knockout cell lines and metabolomics |
| NIT1 | Endothelial oxidative stress and glutamine metabolism | Endothelial cell knockout and stress assays |
| NIT2 | Omega-amidase pathway and nitrogen metabolism | NIT2 knockout and pathway flux analysis |
| GCLC | Glutathione synthesis deficiency and oxidative stress | GCLC knockout or knockdown with rescue |
| GSS | Glutathione synthetase deficiency and redox imbalance | GSS knockout and glutathione measurements |
Metabolic stress and endothelial dysfunction
The transaminase-omega-amidase pathway senses oxidative stress to control glutamine metabolism and alpha-ketoglutarate levels in endothelial cells. Because deaminated glutathione amidase activity is part of this pathway, its dysfunction could contribute to endothelial metabolic stress and vascular dysfunction. Loss of repair capacity would allow deaminated glutathione to accumulate and could deplete the glutathione pool, worsening oxidative damage.
Cancer metabolism
Cancer cells often depend on glutamine and on glutathione for redox balance and proliferation. Deaminated glutathione amidase activity supports both glutathione availability and 2-oxoglutarate supply, two metabolites that are central to cancer metabolism. This makes the activity a candidate for studies of metabolic vulnerability in tumors, although direct clinical evidence is still limited.
Metabolite repair disorders
Nit1 is a metabolite repair enzyme, and defects in metabolite repair can lead to accumulation of damaged metabolites with cellular toxicity. Loss of deaminated glutathione amidase activity would be predicted to cause accumulation of N-(4-oxoglutarate)-L-cysteinylglycine and depletion of L-cysteinylglycine. Such a defect could be studied in cell and animal models as a paradigm for metabolite repair disease.
From deaminated glutathione amidase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of NIT1 abolish deaminated glutathione amidase activity? | NIT1 knockout cell line with biochemical assay |
| Which catalytic residue is required for hydrolysis? | Point-mutation knock-in of predicted catalytic residues |
| Can tagged NIT1 rescue the knockout phenotype? | Knock-in of epitope-tagged NIT1 |
| Does overexpression of NIT1 protect against oxidative stress? | NIT1 overexpression cell line with stress challenge |
| How does the pathway respond to oxidative stress? | Endothelial cells with pathway perturbation and metabolomics |
| Is the activity conserved across species? | Comparative expression of NIT1 orthologs and assay |
How to Study the deaminated glutathione amidase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzymatic activity assay | Hydrolysis of deaminated glutathione to 2-oxoglutarate and L-cysteinylglycine | Confirming GO:0110050 in purified enzyme or lysates |
| Metabolomics | Levels of glutathione, deaminated glutathione, and 2-oxoglutarate | Assessing pathway flux and stress responses |
| Stable-isotope tracing | Carbon and nitrogen flux through glutamine and TCA cycle | Mapping pathway connections |
| CRISPR knockout screening | Genes required for stress resistance or metabolite balance | Identifying pathway components |
| Western blot | Protein expression of NIT1 and pathway enzymes | Validating knockout and overexpression models |
| qRT-PCR | mRNA levels of NIT1 and related genes | Assessing transcriptional regulation |
| Structural biology | Three-dimensional fold and catalytic residues | Mechanistic studies of nitrilase superfamily enzymes |
| Enzyme kinetics | Km, Vmax, and catalytic efficiency | Comparing wild-type and mutant enzymes |
Biochemical activity assays
Deaminated glutathione amidase activity can be measured directly by monitoring the hydrolysis of N-(4-oxoglutarate)-L-cysteinylglycine to 2-oxoglutarate and L-cysteinylglycine. Such assays use purified enzyme or cell lysates and detect product formation by chromatographic or enzymatic methods. These assays are the gold standard for confirming that a candidate gene carries GO:0110050.
Metabolomics and flux analysis
Because the reaction produces 2-oxoglutarate and consumes a glutathione adduct, metabolomic profiling can reveal changes in deaminated glutathione, glutathione, and 2-oxoglutarate levels. Stable-isotope tracing can be used to follow glutamine and glucose carbon into these pools. This approach is especially informative in cells with perturbed transaminase-omega-amidase pathway activity.
CRISPR screening and functional genomics
CRISPR knockout screens can identify genes required for resistance to oxidative stress or for maintenance of glutathione and 2-oxoglutarate pools. Candidate hits can then be validated with targeted knockouts and biochemical assays. This workflow connects GO:0110050 to broader cellular phenotypes.
Structural and mechanistic studies
Structural studies of nitrilase superfamily enzymes have revealed conserved catalytic folds and mechanisms that inform how Nit1 hydrolyzes deaminated glutathione. Mutagenesis of predicted catalytic residues, combined with activity assays, can test mechanistic hypotheses. Comparative analysis with other amidases and nitrilases provides additional mechanistic insight.
How CRISPR Can Be Used to Study GO:0110050 deaminated glutathione amidase activity
Knockout
CRISPR knockout of NIT1 is the most direct way to eliminate deaminated glutathione amidase activity in a cell model. Knockout cells can be challenged with oxidative stress and analyzed by metabolomics to test whether deaminated glutathione accumulates and glutathione is depleted. This design provides causal evidence that NIT1 is responsible for GO:0110050 in the cell type studied.
Point Mutation
Point mutations in predicted catalytic residues of NIT1 can be introduced to test the mechanism of hydrolysis. Comparing wild-type and mutant enzymes in activity assays distinguishes residues required for catalysis from those involved in substrate binding. This approach is valuable because nitrilase superfamily enzymes share conserved catalytic chemistry.
Knock-in
Knock-in of an epitope-tagged NIT1 allows localization and interaction studies while preserving endogenous regulation. Tagged knock-in can also be used to rescue the knockout phenotype and confirm that the observed effects are due to the tagged protein. This strategy is useful for linking the enzyme to specific cellular compartments or complexes.
Overexpression
Overexpression of NIT1 can test whether increased deaminated glutathione amidase activity protects cells from oxidative stress or alters glutamine metabolism. Overexpression models are also useful for producing enough enzyme for biochemical and structural studies. Combining overexpression with stress challenges can reveal dose-dependent effects on glutathione and 2-oxoglutarate pools.
How EDITGENE Supports deaminated glutathione amidase activity Research
Researchers studying deaminated glutathione amidase activity-related genes often need to determine whether a candidate gene is causally involved in the repair of deaminated glutathione, how its catalytic residues work, and whether its loss or gain changes glutathione and 2-oxoglutarate metabolism. Answering these questions requires precise genetic models that can isolate the activity from related pathways and from compensatory changes. EDITGENE provides the full set of CRISPR tools needed to build such models and to interpret the resulting metabolic and phenotypic data.
Contact EDITGENE today to design your custom CRISPR model for deaminated glutathione amidase activity research.
Frequently Asked Questions About deaminated glutathione amidase activity
What is deaminated glutathione amidase activity?
It is a molecular_function (GO:0110050) that catalyzes the reaction N-(4-oxoglutarate)-L-cysteinylglycine + H2O = 2-oxoglutarate + L-cysteinylglycine, repairing a damaged glutathione adduct.
What genes are involved in deaminated glutathione amidase activity?
The principal gene is NIT1, which encodes a nitrilase superfamily enzyme that hydrolyzes deaminated glutathione; related pathway genes include NIT2 and transaminase-omega-amidase components.
Which enzyme carries GO:0110050?
Nit1 is the enzyme identified as a metabolite repair enzyme that hydrolyzes deaminated glutathione.
What is the substrate of deaminated glutathione amidase activity?
The substrate is N-(4-oxoglutarate)-L-cysteinylglycine, a deaminated glutathione adduct.
What are the products of this reaction?
The products are 2-oxoglutarate and L-cysteinylglycine.
Why is deaminated glutathione amidase activity important?
It maintains glutathione availability and supplies 2-oxoglutarate, linking metabolite repair to glutamine metabolism and oxidative stress responses.
How is deaminated glutathione amidase activity regulated?
It is part of the transaminase-omega-amidase pathway that senses oxidative stress and controls glutamine metabolism and alpha-ketoglutarate levels in endothelial cells.
What diseases are linked to deaminated glutathione amidase activity?
It is relevant to metabolic stress, endothelial dysfunction, cancer metabolism, and metabolite repair disorders, although direct clinical evidence is still limited.
How can I study deaminated glutathione amidase activity with CRISPR?
Use NIT1 knockout to eliminate activity, point mutations to test catalytic residues, knock-in for tagging and rescue, and overexpression for gain-of-function studies.
What methods measure deaminated glutathione amidase activity?
Enzymatic activity assays, metabolomics, stable-isotope tracing, and CRISPR screens are commonly used to measure the activity and its pathway effects.
Conclusion
GO:0110050 deaminated glutathione amidase activity defines a precise metabolite repair reaction carried out by Nit1, a nitrilase superfamily enzyme that hydrolyzes deaminated glutathione to 2-oxoglutarate and L-cysteinylglycine. This activity protects glutathione pools and connects repair chemistry to glutamine metabolism and alpha-ketoglutarate levels, particularly under oxidative stress. Understanding its mechanism, regulation, and disease relevance requires well-controlled genetic models and quantitative metabolic assays. CRISPR knockout, point-mutation, knock-in, and overexpression approaches provide the causal evidence needed to move from correlation to function.
References
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- 2. Martínková L et al.. 2010. Biotransformations with nitrilases.. Curr Opin Chem Biol 14(2):130-7 PMID: 20083424
- 3. Brenner C. 2002. Catalysis in the nitrilase superfamily.. Curr Opin Struct Biol 12(6):775-82 PMID: 12504683
- 4. Peracchi A et al.. 2017. Nit1 is a metabolite repair enzyme that hydrolyzes deaminated glutathione.. Proc Natl Acad Sci U S A 114(16):E3233-E3242 PMID: 28373563
- 5. Singh R et al.. 2025. Microbial amidases: Characterization, advances and biotechnological applications.. Biotechnol Notes 6:44-58 PMID: 39811779
- 6. Diao H et al.. 2025. [Advances in the catalytic promiscuity of nitrilases].. Sheng Wu Gong Cheng Xue Bao 41(1):131-147 PMID: 39855685
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