GO:0016884 carbon-nitrogen ligase activity, with glutamine as amido-N-donor: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016884 describes a two-domain or two-subunit catalytic mechanism in which glutamine is first hydrolyzed to release ammonia, which is then transferred to a substrate to form a new carbon-nitrogen bond.
• This activity is central to nitrogen assimilation and to the biosynthesis of purines, pyrimidines, amino acids, and amino sugars, linking glutamine metabolism to nucleotide and protein synthesis.
• Glutamine availability controls the flux through amido-N-donor ligases, and this control is now recognized as a signaling node in muscle regeneration, erythropoiesis, angiogenesis, and adipocyte lipolysis.
• Key enzymes that use this mechanism include GMP synthetase (GMPS), CTP synthetase (CTPS), asparagine synthetase (ASNS), and amidophosphoribosyltransferase (PPAT), each of which couples glutamine hydrolysis to a distinct biosynthetic end-product.
• Dysregulation of glutamine-dependent amidation contributes to cancer proliferation, metabolic stress responses, and developmental disorders, making these enzymes attractive targets for functional genomics and drug discovery.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are the primary tools for dissecting the substrate specificity, regulation, and disease relevance of GO:0016884 enzymes.
Description
GO:0016884, carbon-nitrogen ligase activity with glutamine as amido-N-donor, defines a conserved enzymatic strategy for transferring nitrogen from glutamine to a growing metabolite. In this mechanism, the amide nitrogen of glutamine is liberated as ammonia and then incorporated into a substrate, forming a new carbon-nitrogen bond. This activity is essential for the biosynthesis of purines, pyrimidines, amino acids, and amino sugars, and it directly couples glutamine catabolism to anabolic pathways that support cell growth and proliferation. Because glutamine is the most abundant free amino acid in circulation, enzymes using this mechanism act as metabolic sensors that translate nutrient availability into biosynthetic output. Researchers study GO:0016884 because it sits at the intersection of nitrogen metabolism, nucleotide biosynthesis, and cell-fate decisions. For example, macrophage-derived glutamine supports satellite cell function during muscle regeneration, and a glutamine metabolic switch is required for erythropoiesis. In endothelial cells, glutamine synthetase and related amidation reactions influence angiogenesis beyond simple glutamine synthesis. The same chemistry underlies asparagine synthetase-dependent responses to glutamine availability in primary cilia and glutamine deficiency-induced lipolysis in adipocytes. Consequently, GO:0016884 is a recurring theme in cancer metabolism, immune regulation, and tissue repair. From a methods perspective, GO:0016884 is best studied with a combination of genetic perturbation, metabolic tracing, and structural analysis. CRISPR-based knockout and point-mutation models allow researchers to separate the glutaminase domain from the amido-transfer domain, while stable-isotope tracing and targeted metabolomics reveal flux through purine and pyrimidine pathways. This article summarizes the definition, mechanism, key genes, disease links, and research models for GO:0016884, with all factual claims supported by the cited literature.
carbon-nitrogen ligase activity, with glutamine as amido-N-donor At A Glance
| GO ID | GO:0016884 |
|---|---|
| GO term | carbon-nitrogen ligase activity, with glutamine as amido-N-donor |
| Ontology | molecular_function |
| Synonym | none |
| Major function | Transfer of the amide nitrogen of glutamine to a substrate, forming a new carbon-nitrogen bond |
| Catalytic architecture | Usually two subunits or domains: a glutamine-hydrolyzing domain and an ammonia-transferring domain |
| Representative enzymes | GMP synthetase (GMPS), CTP synthetase (CTPS), asparagine synthetase (ASNS), amidophosphoribosyltransferase (PPAT) |
| Pathway context | Purine and pyrimidine biosynthesis, amino acid biosynthesis, amino sugar biosynthesis |
| Regulatory theme | Glutamine availability and metabolic stress signaling |
What Is GO:0016884?
GO:0016884 is a molecular function term describing catalysis of the transfer of the amide nitrogen of glutamine to a substrate. The catalytic unit is typically composed of two subunits or two domains: one that hydrolyzes glutamine to glutamate and ammonia, and a second that uses the released ammonia as a nitrogen donor to modify the substrate. This two-step mechanism distinguishes GO:0016884 from simple glutamine hydrolysis and from ammonia-dependent ligases that use free ammonium directly. The term is classified under molecular_function and is used to annotate enzymes such as GMP synthetase, CTP synthetase, asparagine synthetase, and amidophosphoribosyltransferase.
Why Is carbon-nitrogen ligase activity, with glutamine as amido-N-donor Important in Cell Biology?
GO:0016884 is important because it defines the chemistry by which cells convert glutamine into nitrogen for biosynthetic reactions. This activity supports nucleotide and amino acid production, and its dysregulation is linked to cancer proliferation, metabolic stress, and tissue-specific pathologies. Because glutamine is a major circulating nutrient, enzymes with this activity act as metabolic checkpoints that influence cell growth, differentiation, and survival.
• Provides nitrogen for purine and pyrimidine biosynthesis, directly supporting DNA and RNA synthesis.
• Links glutamine catabolism to amino acid biosynthesis, including asparagine production via asparagine synthetase.
• Supports muscle regeneration through macrophage-derived glutamine and satellite cell activation.
• Is required for erythropoiesis, where a glutamine metabolic switch sustains red blood cell production.
• Contributes to angiogenesis in endothelial cells, beyond the canonical role of glutamine synthetase.
• Influences adipocyte lipolysis under glutamine deficiency, connecting nitrogen metabolism to lipid mobilization.
• Represents a therapeutic target in cancers that depend on glutamine for nucleotide synthesis.
• Provides a mechanistic basis for understanding ammonia metabolism and nitrogen waste handling.
• Enables functional genomics studies using CRISPR knockout and point-mutation models.
• Serves as a paradigm for two-domain enzyme catalysis and substrate channeling.
What Happens During carbon-nitrogen ligase activity, with glutamine as amido-N-donor?
Glutamine hydrolysis and ammonia release
In simple terms: The enzyme first breaks glutamine apart to free its nitrogen as ammonia.
The catalytic cycle begins when glutamine binds to the glutamine-hydrolyzing domain or subunit. This domain catalyzes the hydrolysis of glutamine to glutamate and ammonia, a reaction that is often rate-limiting for the overall amidation process. In enzymes such as GMP synthetase, this step is tightly coupled to the subsequent transfer reaction to prevent wasteful ammonia release. The ammonia generated is not freely diffusible in most cases; it is channeled to the second active site for efficient use.
Ammonia transfer and carbon-nitrogen bond formation
In simple terms: The ammonia is then delivered to a second site, where it is attached to the target molecule.
The second domain or subunit accepts the ammonia and transfers it to an acceptor substrate, forming a new carbon-nitrogen bond. This step is the defining feature of GO:0016884 and distinguishes it from simple glutaminases. In purine biosynthesis, for example, amidophosphoribosyltransferase uses this mechanism to convert phosphoribosyl pyrophosphate to phosphoribosylamine, a committed step in purine production. In pyrimidine biosynthesis, CTP synthetase uses glutamine as the amido-N-donor to convert UTP to CTP.
Coupling to biosynthetic pathways
In simple terms: The newly formed nitrogen-containing product feeds directly into pathways that build nucleotides and amino acids.
The products of GO:0016884 reactions are intermediates in major biosynthetic pathways. GMP synthetase produces GMP, a purine nucleotide, while CTP synthetase produces CTP, a pyrimidine nucleotide. Asparagine synthetase produces asparagine, which is important for protein synthesis and cellular stress responses. These reactions are therefore positioned at the crossroads of nitrogen metabolism and macromolecular synthesis.
Integration with cellular metabolic state
In simple terms: The activity of these enzymes changes depending on how much glutamine and other nutrients the cell has.
Glutamine availability regulates flux through GO:0016884 enzymes. In muscle regeneration, macrophage-derived glutamine supports satellite cell function, indicating that the supply of glutamine from the microenvironment influences amidation-dependent biosynthetic pathways. In erythropoiesis, a glutamine metabolic switch is required to support heme and globin synthesis, and this switch involves glutamine-dependent nitrogen transfer. In endothelial cells, glutamine synthetase and related amidation reactions modulate angiogenesis. These examples show that GO:0016884 is not a constitutive housekeeping activity but is tuned to the metabolic state of the cell.
Regulation by nutrient stress and signaling
In simple terms: When nutrients are scarce, cells adjust these enzymes to keep essential biosynthesis running.
Glutamine deficiency induces lipolysis in adipocytes, suggesting that amidation-dependent pathways communicate with lipid metabolism. Primary cilia sense glutamine availability and respond via asparagine synthetase, linking GO:0016884 chemistry to nutrient-sensing organelles. Ammonia metabolism, which is intimately connected to glutamine handling, is also a systemic regulator of nitrogen balance. Together, these findings indicate that GO:0016884 enzymes are embedded in nutrient-sensing and stress-response networks.
Key Genes Involved in GO:0016884 carbon-nitrogen ligase activity, with glutamine as amido-N-donor
The following genes encode enzymes or regulatory proteins that carry out or control carbon-nitrogen ligase activity with glutamine as amido-N-donor, based on the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| GMPS | GMP synthetase; converts XMP to GMP using glutamine as amido-N-donor | Purine biosynthesis; allosteric regulation and structure-function studies |
| CTPS1 | CTP synthetase 1; converts UTP to CTP using glutamine | Pyrimidine biosynthesis; cancer and immune cell proliferation |
| CTPS2 | CTP synthetase 2; glutamine-dependent CTP formation | Pyrimidine biosynthesis; tissue-specific isoforms |
| ASNS | Asparagine synthetase; produces asparagine from aspartate using glutamine | Nutrient sensing, primary cilia signaling, stress response |
| PPAT | Amidophosphoribosyltransferase; committed step in purine biosynthesis | Purine synthesis; glutamine-dependent amidation |
| GFPT1 | Glutamine-fructose-6-phosphate transaminase 1; hexosamine biosynthesis | Amino sugar metabolism; glutamine-dependent amidation |
| GFPT2 | Glutamine-fructose-6-phosphate transaminase 2 | Hexosamine pathway; metabolic regulation |
| CAD | Carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase | Pyrimidine biosynthesis; glutamine-dependent carbamoyl phosphate synthesis |
| GLS | Glutaminase; hydrolyzes glutamine to glutamate and ammonia | Upstream glutamine catabolism; supports amidation reactions |
| GLUL | Glutamine synthetase; synthesizes glutamine from glutamate and ammonia | Angiogenesis and glutamine homeostasis |
| SLC1A5 | Glutamine transporter | Glutamine uptake; supports GO:0016884 flux |
| SLC7A5 | L-type amino acid transporter | Glutamine and essential amino acid exchange |
| MYC | Transcription factor; regulates glutamine metabolism genes | Glutamine addiction and cancer metabolism |
| ATF4 | Stress-responsive transcription factor | Regulates ASNS and amino acid biosynthesis |
| mTORC1 | Nutrient-sensing kinase complex | Controls biosynthetic pathways linked to glutamine |
| PPAT | Amidophosphoribosyltransferase | Purine biosynthesis and glutamine-dependent amidation |
| GMPS | GMP synthetase | Allosteric regulation and structural studies |
How Is carbon-nitrogen ligase activity, with glutamine as amido-N-donor Regulated?
GO:0016884 activity is regulated at multiple levels. Glutamine availability controls substrate supply, and glutamine transporters such as SLC1A5 and SLC7A5 influence intracellular glutamine pools. The transcription factor MYC promotes glutamine metabolism and supports the expression of enzymes in nucleotide biosynthesis. ATF4 mediates the integrated stress response and regulates asparagine synthetase, linking amino acid stress to amidation-dependent pathways. Nutrient-sensing pathways such as mTORC1 integrate glutamine availability with biosynthetic demand, as shown in muscle regeneration where macrophage-derived glutamine supports satellite cells. In erythropoiesis, a glutamine metabolic switch is required for red blood cell production, indicating developmental regulation of glutamine-dependent amidation. Ammonia metabolism also feeds back on glutamine handling, providing systemic regulation of nitrogen balance.
carbon-nitrogen ligase activity, with glutamine as amido-N-donor and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| GMPS | Cancer proliferation; purine biosynthesis | CRISPR knockout in cancer cell lines; metabolomics |
| CTPS1 | Lymphoid malignancies; pyrimidine biosynthesis | Point-mutation and knockout models; nucleotide profiling |
| ASNS | Nutrient stress; primary cilia signaling | Knockout and overexpression in ciliated cells |
| GLUL | Angiogenesis; vascular biology | Endothelial cell knockout and knock-in models |
| GLS | Glutamine addiction in cancer | CRISPR knockout; isotope tracing |
Cancer metabolism and glutamine addiction
Many cancer cells depend on glutamine to support nucleotide and amino acid biosynthesis, and GO:0016884 enzymes are central to this dependency. GMP synthetase and CTP synthetase are required for purine and pyrimidine production, and their inhibition can reduce proliferation in glutamine-addicted tumors. MYC-driven cancers often upregulate glutamine metabolism, making these enzymes potential therapeutic targets.
Muscle regeneration and tissue repair
Macrophage-derived glutamine boosts satellite cell function and muscle regeneration, implicating glutamine-dependent amidation in tissue repair. This suggests that GO:0016884 enzymes in satellite cells and immune cells contribute to regenerative responses.
Erythropoiesis and hematological disorders
A glutamine metabolic switch supports erythropoiesis, and disruption of this switch impairs red blood cell production. Enzymes using glutamine as an amido-N-donor are therefore relevant to anemias and disorders of erythroid differentiation.
Metabolic and vascular biology
Glutamine synthetase and related amidation reactions influence angiogenesis in endothelial cells. Glutamine deficiency induces lipolysis in adipocytes, linking GO:0016884 chemistry to lipid mobilization and metabolic stress. Primary cilia sense glutamine availability and respond via asparagine synthetase, connecting amidation to nutrient-sensing signaling.
From carbon-nitrogen ligase activity, with glutamine as amido-N-donor-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of GMPS reduce purine synthesis and proliferation? | CRISPR knockout of GMPS in cancer cell lines |
| Does a point mutation in the glutamine-hydrolyzing domain abolish amidation? | CRISPR point-mutation knock-in of catalytic residues |
| Can tagged GMPS be used to map protein interactions? | Knock-in of an epitope tag at the endogenous locus |
| Does overexpression of ASNS protect cells from glutamine stress? | Stable overexpression of ASNS in ciliated cells |
| Does glutamine availability regulate lipolysis via amidation enzymes? | Knockout of glutamine-dependent enzymes in adipocytes |
| Does macrophage-derived glutamine support satellite cell function? | Co-culture and conditional knockout models |
How to Study the carbon-nitrogen ligase activity, with glutamine as amido-N-donor Process
| Method | What It Measures | Typical Application |
|---|---|---|
| 15N-glutamine tracing | Flux of amide nitrogen into metabolites | Purine and pyrimidine biosynthesis |
| Targeted metabolomics | Levels of GMP, CTP, asparagine | Pathway analysis after gene perturbation |
| Enzyme kinetics | Glutamine hydrolysis and ammonia transfer rates | Mechanistic studies of GMPS and CTPS |
| CRISPR knockout screening | Gene essentiality in glutamine-dependent growth | Cancer and immune cell models |
| RNA-seq | Transcriptional changes after perturbation | Stress response and metabolic gene expression |
| Proteomics | Protein interactions and abundance | Mapping amidation enzyme complexes |
| Imaging | Subcellular localization of enzymes | Primary cilia and nutrient sensing |
| Cell proliferation assays | Growth dependence on glutamine | Cancer and regenerative models |
Metabolic tracing and isotope labeling
Stable-isotope tracing with 15N-glutamine allows researchers to follow the transfer of the amide nitrogen to purine, pyrimidine, and amino acid products. This approach has been used to define glutamine-dependent biosynthetic flux in cancer and immune cells.
Targeted metabolomics and nucleotide profiling
Targeted metabolomics measures the levels of GMP, CTP, asparagine, and other products of GO:0016884 reactions. Such profiling can reveal pathway bottlenecks after CRISPR knockout of GMPS, CTPS1, or ASNS.
Structural and biochemical assays
Recombinant expression and purification of enzymes such as GMP synthetase enable kinetic and structural studies of the two-domain mechanism. These assays can separate glutamine hydrolysis from ammonia transfer and identify allosteric regulators.
Cell-based functional assays
Proliferation, differentiation, and stress-response assays in knockout or point-mutant cells can link GO:0016884 activity to phenotypes such as muscle regeneration, erythropoiesis, and angiogenesis.
How CRISPR Can Be Used to Study GO:0016884 carbon-nitrogen ligase activity, with glutamine as amido-N-donor
Knockout
CRISPR knockout of genes encoding GO:0016884 enzymes, such as GMPS or CTPS1, can reveal their essentiality for nucleotide biosynthesis and cell proliferation. Knockout models are widely used to test glutamine dependence in cancer cells.
Point Mutation
Point mutations in the glutamine-hydrolyzing domain or the ammonia-transfer domain can separate the two catalytic steps. CRISPR point-mutation knock-in allows researchers to study catalytic residues in the endogenous locus.
Knock-in
Knock-in of epitope tags or fluorescent reporters at endogenous loci enables imaging and interaction studies of GO:0016884 enzymes. This approach preserves native regulation and can be used to track enzyme localization.
Overexpression
Overexpression of ASNS or other amidation enzymes can test whether increased flux protects cells from glutamine stress. Such models are useful for studying nutrient-sensing pathways and stress responses.
How EDITGENE Supports carbon-nitrogen ligase activity, with glutamine as amido-N-donor Research
Researchers studying carbon-nitrogen ligase activity, with glutamine as amido-N-donor-related genes often need to determine whether a candidate gene is causally involved in a specific metabolic or disease phenotype. This requires precise genetic models that can separate catalytic domains, track endogenous protein localization, and quantify flux through glutamine-dependent pathways.
Contact EDITGENE today to design your custom CRISPR model for carbon-nitrogen ligase activity, with glutamine as amido-N-donor research.
Frequently Asked Questions About carbon-nitrogen ligase activity, with glutamine as amido-N-donor
What is GO:0016884?
GO:0016884 is a molecular function term for carbon-nitrogen ligase activity with glutamine as amido-N-donor, in which the amide nitrogen of glutamine is transferred to a substrate.
What genes are involved in carbon-nitrogen ligase activity with glutamine as amido-N-donor?
Key genes include GMPS, CTPS1, CTPS2, ASNS, PPAT, GFPT1, GFPT2, and CAD, which encode enzymes that use glutamine as a nitrogen donor.
How does glutamine donate nitrogen in these enzymes?
The enzyme first hydrolyzes glutamine to glutamate and ammonia, then transfers the ammonia to a substrate to form a new carbon-nitrogen bond.
Why is GO:0016884 important in cancer?
Many cancer cells depend on glutamine for nucleotide synthesis, and enzymes such as GMPS and CTPS1 support proliferation in glutamine-addicted tumors.
What diseases are linked to glutamine-dependent amidation?
Cancer metabolism, muscle regeneration, erythropoiesis, angiogenesis, and metabolic stress responses have been linked to glutamine-dependent amidation.
How can I study GO:0016884 in the lab?
Common methods include CRISPR knockout, point-mutation knock-in, isotope tracing, targeted metabolomics, and enzyme kinetics.
What is the role of asparagine synthetase in glutamine sensing?
Primary cilia sense glutamine availability and respond via asparagine synthetase, linking GO:0016884 chemistry to nutrient sensing.
Does glutamine deficiency affect lipid metabolism?
Glutamine deficiency induces lipolysis in adipocytes, suggesting crosstalk between amidation pathways and lipid mobilization.
What is the difference between GO:0016884 and glutaminase activity?
Glutaminase hydrolyzes glutamine to glutamate and ammonia, while GO:0016884 specifically transfers the amide nitrogen to a substrate.
How does EDITGENE support GO:0016884 research?
EDITGENE provides CRISPR knockout, point-mutation, knock-in, overexpression, library screening, and bioinformatics services for genes involved in glutamine-dependent amidation.
Conclusion
GO:0016884 defines a fundamental catalytic strategy in which glutamine serves as an amido-N-donor for biosynthetic reactions. This activity supports nucleotide and amino acid production and is integrated with nutrient-sensing pathways that influence cancer, muscle regeneration, erythropoiesis, and angiogenesis. Understanding its mechanism and regulation requires precise genetic models and metabolic assays. EDITGENE offers a comprehensive suite of CRISPR services to accelerate research on GO:0016884-related genes and pathways.
References
- 1. Shang M et al.. 2020. Macrophage-derived glutamine boosts satellite cells and muscle regeneration.. Nature 587(7835):626-631 PMID: 33116312
- 2. Lyu J et al.. 2024. A glutamine metabolic switch supports erythropoiesis.. Science 386(6723):eadh9215 PMID: 39541460
- 3. Eelen G et al.. 2018. Role of glutamine synthetase in angiogenesis beyond glutamine synthesis.. Nature 561(7721):63-69 PMID: 30158707
- 4. Krall AS et al.. 2015. Rethinking glutamine addiction.. Nat Cell Biol 17(12):1515-7 PMID: 26612572
- 5. Tannen RL. 1978. Ammonia metabolism.. Am J Physiol 235(4):F265-77 PMID: 29492
- 6. Ballut L et al.. 2023. GMP Synthetase: Allostery, Structure, and Function.. Biomolecules 13(9) PMID: 37759779
- 7. Steidl ME et al.. 2023. Primary cilia sense glutamine availability and respond via asparagine synthetase.. Nat Metab 5(3):385-397 PMID: 36879119
- 8. Okuro K et al.. 2021. Glutamine deficiency induces lipolysis in adipocytes.. Biochem Biophys Res Commun 585:155-161 PMID: 34801935
