GO:0030409 glutamate formimidoyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0030409 glutamate formimidoyltransferase activity catalyzes the reversible transfer of a formimidoyl group from 5-formimidoyltetrahydrofolate to L-glutamate, yielding tetrahydrofolate and N-formimidoyl-L-glutamate.
• The enzyme is classically known as formiminotransferase and is part of the bifunctional formiminotransferase-cyclodeaminase (FTCD) protein in humans.
• FTCD channeling between formiminotransferase and cyclodeaminase active sites allows efficient folate metabolism without releasing the intermediate.
• Biallelic loss-of-function variants in FTCD cause glutamate formiminotransferase deficiency, a rare inborn error of folate metabolism with elevated formiminoglutamate in urine.
• Plant and other non-mammalian glutamate formiminotransferases can moonlight as 5-formyltetrahydrofolate cycloligases, revealing evolutionary flexibility of this activity.
• Studying GO:0030409 requires combining enzyme assays, metabolic profiling, and CRISPR-based models to dissect its role in one-carbon metabolism and disease.
Description
Glutamate formimidoyltransferase activity (GO:0030409) is a molecular function that sits at the intersection of histidine catabolism and one-carbon folate metabolism. It catalyzes the reversible transfer of a formimidoyl group from 5-formimidoyltetrahydrofolate to L-glutamate, producing tetrahydrofolate and N-formimidoyl-L-glutamate. This reaction is essential for recycling tetrahydrofolate, a central cofactor for nucleotide biosynthesis and methylation reactions. In humans, the activity is carried by the bifunctional enzyme formiminotransferase-cyclodeaminase (FTCD), which couples transfer and deamination to optimize folate handling. Researchers study GO:0030409 because its dysfunction leads to a rare metabolic disorder, glutamate formiminotransferase deficiency, and because it exemplifies enzyme channeling and multifunctional protein organization. Understanding this activity also informs broader questions about folate-dependent pathways in development, liver function, and disease.
glutamate formimidoyltransferase activity At A Glance
| GO ID | GO:0030409 |
|---|---|
| GO term | glutamate formimidoyltransferase activity |
| Ontology | molecular_function |
| Synonym | formiminotransferase activity; glutamate formyltransferase activity; formiminoglutamic acid transferase activity; 5-formimidoyltetrahydrofolate:L-glutamate N-formimidoyltransferase activity |
| Major function | Transfer of a formimidoyl group from 5-formimidoyltetrahydrofolate to L-glutamate, yielding tetrahydrofolate and N-formimidoyl-L-glutamate |
| Cofactor | Tetrahydrofolate (as acceptor/donor in the reversible reaction) |
| Substrates | 5-formimidoyltetrahydrofolate and L-glutamate |
| Products | Tetrahydrofolate and N-formimidoyl-L-glutamate |
| Associated human gene | FTCD (formiminotransferase cyclodeaminase) |
| Related disease | Glutamate formiminotransferase deficiency |
What Is GO:0030409?
GO:0030409 glutamate formimidoyltransferase activity is defined as the catalysis of the reaction: 5-formimidoyltetrahydrofolate + L-glutamate = tetrahydrofolate + N-formimidoyl-L-glutamate. In other words, the enzyme transfers a formimidoyl group from a folate derivative to glutamate, regenerating tetrahydrofolate. This activity is also known by synonyms such as formiminotransferase activity, glutamate formyltransferase activity, and formiminoglutamic acid transferase activity. It belongs to the molecular_function ontology and is typically measured by monitoring the formation of N-formimidoyl-L-glutamate or the release of tetrahydrofolate.
Why Is glutamate formimidoyltransferase activity Important in Cell Biology?
GO:0030409 is important because it links histidine degradation to folate one-carbon pools, which are required for DNA synthesis, amino acid metabolism, and methylation. The reaction regenerates tetrahydrofolate, a critical cofactor, and its dysfunction can cause formiminoglutamic aciduria and altered folate status. The bifunctional FTCD enzyme that carries this activity in humans also provides a paradigm for substrate channeling, where consecutive active sites cooperate to prevent wasteful release of intermediates. Moreover, the discovery that some glutamate formiminotransferases can moonlight as 5-formyltetrahydrofolate cycloligases highlights unexpected functional plasticity relevant to folate metabolism across species. Clinically, understanding this activity helps interpret metabolic screens and genetic variants in patients with suspected inborn errors of folate metabolism.
• Regenerates tetrahydrofolate, a central one-carbon carrier for nucleotide and methionine synthesis.
• Connects histidine catabolism to folate metabolism via the formiminoglutamate pathway.
• Deficiency causes a rare metabolic disorder with elevated formiminoglutamate in urine.
• FTCD, the human enzyme, is bifunctional and exhibits substrate channeling between two active sites.
• Some glutamate formiminotransferases can moonlight as 5-formyltetrahydrofolate cycloligases, expanding functional roles.
• Folate enzyme patterns differ between premature and full-term infants, suggesting developmental regulation.
• The activity is relevant to liver biology, as FTCD is highly expressed in liver and its isoforms localize to Golgi and other compartments.
• Autoimmune hepatitis models show altered immune regulation that may intersect with metabolic pathways, though direct links to GO:0030409 remain to be defined.
• Enzyme assays for this activity are used in clinical diagnostics of folate disorders.
• CRISPR models of FTCD can help dissect its role in one-carbon metabolism and disease.
What Happens During glutamate formimidoyltransferase activity?
Substrate binding and formimidoyl transfer
In simple terms: The enzyme grabs a formimidoyl group from one molecule and hands it to another.
The reaction begins when 5-formimidoyltetrahydrofolate and L-glutamate bind to the formiminotransferase active site. The enzyme transfers the formimidoyl group from the folate derivative to glutamate, forming N-formimidoyl-L-glutamate and releasing tetrahydrofolate. This step is reversible and is the defining catalytic event of GO:0030409.
Channeling to the cyclodeaminase site
In simple terms: The product is passed directly to a second active site without floating away.
In the bifunctional human enzyme FTCD, the N-formimidoyl-L-glutamate produced by the transferase domain is channeled to the adjacent cyclodeaminase active site. Kinetic and binding studies show that this channeling prevents the intermediate from diffusing away, enhancing overall efficiency. This coupling is a classic example of substrate channeling in folate metabolism.
Tetrahydrofolate regeneration
In simple terms: The reaction replenishes the folate pool needed for many cellular processes.
By converting 5-formimidoyltetrahydrofolate back to tetrahydrofolate, the activity maintains the pool of this essential cofactor. Tetrahydrofolate is required for one-carbon transfer reactions in nucleotide synthesis and amino acid metabolism. Thus, GO:0030409 indirectly supports cell proliferation and methylation.
Moonlighting cycloligase activity
In simple terms: Some versions of the enzyme can do a second, unrelated job.
Certain glutamate formiminotransferases, particularly from plants, can functionally replace 5-formyltetrahydrofolate cycloligase, an enzyme in folate interconversion. This moonlighting activity demonstrates that the protein scaffold can accommodate different catalytic functions. It suggests evolutionary flexibility in folate enzyme networks.
Key Genes Involved in GO:0030409 glutamate formimidoyltransferase activity
The following genes and proteins are directly or indirectly associated with glutamate formimidoyltransferase activity (GO:0030409) based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FTCD | Encodes the bifunctional formiminotransferase-cyclodeaminase enzyme that carries GO:0030409 in humans | Mutations cause glutamate formiminotransferase deficiency; model for enzyme channeling |
| MTHFR | Folate metabolism enzyme upstream of tetrahydrofolate pools | Indirectly affects substrate availability for GO:0030409 |
| MTR | Methionine synthase, consumes tetrahydrofolate derivatives | Links folate cycle to methylation; potential crosstalk |
| SHMT1 | Serine hydroxymethyltransferase, contributes to one-carbon pools | May influence tetrahydrofolate availability |
| SHMT2 | Mitochondrial serine hydroxymethyltransferase | Supports one-carbon metabolism; indirect relevance |
| MTHFD1 | Methylenetetrahydrofolate dehydrogenase | Folate interconversion; may affect substrate supply |
| MTHFD2 | Mitochondrial folate enzyme | One-carbon metabolism; indirect |
| GART | Purine synthesis, consumes folate cofactors | Downstream demand for tetrahydrofolate |
| TYMS | Thymidylate synthase, uses folate cofactor | Downstream demand for tetrahydrofolate |
| ATIC | Purine biosynthesis | Indirect link to folate pools |
| DHFR | Dihydrofolate reductase, regenerates tetrahydrofolate | Maintains folate cofactor pool |
| FPGS | Folylpolyglutamate synthetase | Polyglutamation affects enzyme interactions |
| GGH | Gamma-glutamyl hydrolase | Folate polyglutamation; indirect |
| SLC19A1 | Folate transporter | Uptake of folate; indirect |
| MTHFS | 5-formyltetrahydrofolate cycloligase | Moonlighting relationship with formiminotransferases |
| HIST1H1C | Histidine metabolism (representative) | Histidine catabolism feeds formiminoglutamate |
| HAL | Histidine ammonia-lyase | Histidine degradation upstream of formiminoglutamate |
| AMDHD1 | Probable imidazolonepropionase | Histidine catabolism; indirect |
How Is glutamate formimidoyltransferase activity Regulated?
The activity of glutamate formimidoyltransferase is primarily regulated by substrate availability and the bifunctional architecture of FTCD. Polyglutamation of folates affects interaction with the enzyme, as tetrahydropteroylpolyglutamates bind with different affinities to folate-dependent multifunctional enzymes. The enzyme is also subject to developmental regulation, as liver folate enzyme patterns differ between premature and full-term infants. Additionally, FTCD isoforms localize to the Golgi complex and can mediate interaction of trans-Golgi network-derived vesicles with microtubules, suggesting non-metabolic roles that may be regulated by cellular context. No direct allosteric regulators have been firmly established in the provided literature.
glutamate formimidoyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FTCD | Glutamate formiminotransferase deficiency | FTCD knockout or point-mutation knock-in in HepG2 or patient fibroblasts |
| FTCD | Folate metabolism imbalance | Liver-specific FTCD knockout mouse |
| MTHFR | Folate-related disorders | MTHFR knockout or overexpression cell lines |
| MTR | Methylation disorders | MTR knockout in HEK293 |
| HAL | Histidine metabolism disorders | HAL knockout cell model |
Glutamate formiminotransferase deficiency
Biallelic mutations in FTCD cause glutamate formiminotransferase deficiency, an inborn error of folate metabolism characterized by elevated formiminoglutamate in urine and variable neurological symptoms. Molecular analysis has identified missense, nonsense, and splice-site variants that abolish or reduce enzyme activity. Diagnosis relies on metabolic testing and genetic confirmation.
Folate-related metabolic disorders
Because GO:0030409 regenerates tetrahydrofolate, its dysfunction can perturb one-carbon metabolism, affecting nucleotide synthesis and methylation. This may contribute to broader folate-related phenotypes, although direct evidence for specific disorders beyond FTCD deficiency is limited.
Autoimmune hepatitis and immune regulation
Experimental autoimmune hepatitis models show that regulatory T cells and immune pathways influence liver inflammation. While direct links to glutamate formimidoyltransferase activity are not established, FTCD is highly expressed in liver, and metabolic perturbations could intersect with immune-mediated liver damage.
From glutamate formimidoyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of FTCD abolish GO:0030409 activity? | FTCD knockout in HepG2 or HEK293 cells |
| Do patient variants impair enzyme function? | Point-mutation knock-in of FTCD variants |
| Can tagged FTCD reveal subcellular localization? | Knock-in of FLAG- or GFP-tagged FTCD |
| Does FTCD overexpression alter folate pools? | FTCD overexpression in liver cell lines |
| Can moonlighting cycloligase activity be separated? | Point mutations in FTCD active sites |
| Does FTCD channeling require both domains? | Domain-deletion knock-in models |
How to Study the glutamate formimidoyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme assay | Formimidoyl transfer rate | Diagnosis of FTCD deficiency |
| Mass spectrometry | Formiminoglutamate levels | Metabolic profiling |
| Western blot | FTCD protein expression | Knockout validation |
| Immunofluorescence | Subcellular localization | Golgi association |
| CRISPR screen | Gene dependencies | Folate pathway modifiers |
| RNA-seq | Transcriptional changes | Pathway analysis |
| Proteomics | Protein interactions | Channeling partners |
Enzyme activity assays
Direct measurement of GO:0030409 uses spectrophotometric or radiometric assays that monitor the transfer of the formimidoyl group from 5-formimidoyltetrahydrofolate to L-glutamate. These assays are essential for confirming loss-of-function variants in FTCD.
Metabolic profiling
Urine or plasma formiminoglutamate levels are elevated in FTCD deficiency and can be measured by mass spectrometry or colorimetric methods. This provides a functional readout of pathway flux.
Subcellular localization imaging
Fluorescence microscopy of tagged FTCD isoforms reveals Golgi and cytoskeletal associations, informing non-metabolic roles. Co-localization with Golgi markers confirms specific compartments.
CRISPR screening and bioinformatics
Genome-wide CRISPR screens can identify modifiers of folate metabolism and FTCD dependency. Bioinformatics analysis of patient variants helps prioritize pathogenic alleles.
How CRISPR Can Be Used to Study GO:0030409 glutamate formimidoyltransferase activity
Knockout
CRISPR knockout of FTCD in liver cell lines abolishes glutamate formimidoyltransferase activity, providing a clean model to study metabolic consequences and compensatory pathways.
Point Mutation
Introducing patient-specific missense variants into FTCD via CRISPR base editing or HDR allows functional assessment of enzyme activity and stability.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the endogenous FTCD locus enables real-time tracking of localization and interactions without overexpression artifacts.
Overexpression
Overexpression of wild-type or mutant FTCD in cell lines can reveal dominant effects on folate metabolism and substrate channeling.
How EDITGENE Supports glutamate formimidoyltransferase activity Research
Researchers studying glutamate formimidoyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in metabolic flux, disease phenotypes, or drug response. EDITGENE provides a suite of CRISPR services to create precisely engineered cell models that answer these questions.
Contact EDITGENE today to design your custom CRISPR model for glutamate formimidoyltransferase activity research.
Frequently Asked Questions About glutamate formimidoyltransferase activity
What is glutamate formimidoyltransferase activity?
It is a molecular function (GO:0030409) that catalyzes the transfer of a formimidoyl group from 5-formimidoyltetrahydrofolate to L-glutamate, producing tetrahydrofolate and N-formimidoyl-L-glutamate.
What genes are involved in glutamate formimidoyltransferase activity?
The primary human gene is FTCD, which encodes the bifunctional formiminotransferase-cyclodeaminase enzyme. Other folate metabolism genes may indirectly influence the pathway.
What is the role of FTCD in folate metabolism?
FTCD carries both formiminotransferase and cyclodeaminase activities, channeling the intermediate to regenerate tetrahydrofolate efficiently.
What diseases are associated with glutamate formimidoyltransferase deficiency?
Biallelic FTCD mutations cause glutamate formiminotransferase deficiency, characterized by formiminoglutamic aciduria and variable neurological symptoms.
How is glutamate formimidoyltransferase activity measured?
Enzyme assays monitor the transfer of the formimidoyl group, often using spectrophotometric or radiometric detection.
Can CRISPR be used to study FTCD function?
Yes, CRISPR knockout, point mutation, and knock-in models allow precise dissection of FTCD roles in folate metabolism and disease.
What are the symptoms of glutamate formiminotransferase deficiency?
Symptoms may include developmental delay, seizures, and elevated formiminoglutamate in urine, though presentation varies.
Is glutamate formimidoyltransferase activity found in plants?
Yes, plant glutamate formiminotransferases can moonlight as 5-formyltetrahydrofolate cycloligases, indicating evolutionary conservation.
How does substrate channeling work in FTCD?
The formiminotransferase and cyclodeaminase active sites are coupled, allowing the intermediate to pass directly without diffusion, as shown by kinetic studies.
What model systems are used to study GO:0030409?
Liver cell lines, patient fibroblasts, and knockout mouse models are commonly used, along with CRISPR-engineered cells.
Conclusion
Glutamate formimidoyltransferase activity (GO:0030409) is a key enzymatic function that bridges histidine catabolism and folate one-carbon metabolism. Its human representative, FTCD, is a bifunctional enzyme with substrate channeling properties, and its deficiency causes a rare metabolic disorder. Studying this activity with CRISPR models and metabolic assays continues to reveal insights into folate biology and disease.
References
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- 2. Jeanguenin L et al.. 2010. Moonlighting glutamate formiminotransferases can functionally replace 5-formyltetrahydrofolate cycloligase.. J Biol Chem 285(53):41557-66 PMID: 20952389
- 3. Paquin J et al.. 1985. Channeling between the active sites of formiminotransferase-cyclodeaminase. Binding and kinetic studies.. J Biol Chem 260(28):14925-31 PMID: 4066660
- 4. MacKenzie RE et al.. 1983. Interaction of tetrahydropteroylpolyglutamates with two folate-dependent multifunctional enzymes.. Adv Exp Med Biol 163:19-34 PMID: 6412522
- 5. Hennig D et al.. 1998. A formiminotransferase cyclodeaminase isoform is localized to the Golgi complex and can mediate interaction of trans-Golgi network-derived vesicles with microtubules.. J Biol Chem 273(31):19602-11 PMID: 9677386
- 6. Yuksel M et al.. 2016. The induction of autoimmune hepatitis in the human leucocyte antigen-DR4 non-obese diabetic mice autoimmune hepatitis mouse model.. Clin Exp Immunol 186(2):164-176 PMID: 27414259
- 7. Lapierre P et al.. 2010. Forkhead box p3+ regulatory T cell underlies male resistance to experimental type 2 autoimmune hepatitis.. Hepatology 51(5):1789-98 PMID: 20232291
- 8. Kalnitsky A et al.. 1982. Differences in liver folate enzyme patterns in premature and full term infants.. Pediatr Res 16(8):628-31 PMID: 7050870
