GO:0003837 beta-ureidopropionase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003837 beta-ureidopropionase activity is a molecular function that catalyzes the final step of pyrimidine degradation, converting N-carbamoyl-beta-alanine to beta-alanine, ammonia, and CO2.
• The enzyme is encoded by UPB1 in humans; biallelic UPB1 mutations cause beta-ureidopropionase deficiency, an inborn error of pyrimidine metabolism with neurological and urogenital manifestations.
• Beta-ureidopropionase activity is clinically relevant to fluoropyrimidine chemotherapy because it participates in the activation and detoxification of 5-fluorouracil.
• The enzyme is allosterically regulated, and its catalytic activity depends on the stability of active-site loops and subunit interfaces.
• Loss of beta-ureidopropionase activity leads to accumulation of N-carbamoyl-beta-alanine and related metabolites, which can be detected by HPLC-electrospray tandem mass spectrometry.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential for dissecting UPB1 function and for validating disease-associated variants.
Description
GO:0003837 beta-ureidopropionase activity is a molecular function that catalyzes the terminal step of the pyrimidine degradation pathway, the hydrolysis of N-carbamoyl-beta-alanine to beta-alanine, ammonia, and carbon dioxide. This activity is essential for the complete catabolism of uracil and thymine and for the recycling of pyrimidine nitrogen. In humans, the enzyme is encoded by the UPB1 gene, and its deficiency is an autosomal recessive inborn error of metabolism associated with a broad spectrum of neurological abnormalities. Beyond inherited metabolic disease, beta-ureidopropionase activity is directly relevant to cancer pharmacology because it modulates the metabolism of fluoropyrimidine drugs such as 5-fluorouracil. Understanding the molecular mechanism, regulation, and genetic variation of beta-ureidopropionase is therefore important for both rare disease diagnostics and precision oncology. This article integrates authoritative QuickGO annotation data with verified PubMed literature to provide a research-grade overview of GO:0003837, its associated genes, disease links, and experimental strategies.
beta-ureidopropionase activity At A Glance
| GO ID | GO:0003837 |
|---|---|
| GO term | beta-ureidopropionase activity |
| Ontology | Molecular function |
| Synonym | None listed in QuickGO |
| Major function | Catalyzes the final step of pyrimidine degradation: N-carbamoyl-beta-alanine to beta-alanine, ammonia, and CO2 |
| Human gene | UPB1 |
| Pathway | Pyrimidine degradation |
| Disease association | Beta-ureidopropionase deficiency; neurological and urogenital abnormalities |
| Clinical relevance | Fluoropyrimidine chemotherapy metabolism |
What Is GO:0003837?
Beta-ureidopropionase activity (GO:0003837) is the catalytic function that hydrolyzes N-carbamoyl-beta-alanine to produce beta-alanine, ammonia, and carbon dioxide. This activity represents the third and final enzymatic step in the pyrimidine degradation pathway, following dihydropyrimidine dehydrogenase and dihydropyrimidinase. The enzyme belongs to the amidohydrolase superfamily and requires divalent metal ions for catalysis. In humans, this activity is encoded by the UPB1 gene, and its loss-of-function variants cause beta-ureidopropionase deficiency.
Why Is beta-ureidopropionase activity Important in Cell Biology?
Beta-ureidopropionase activity is important because it completes the pyrimidine degradation pathway and its dysfunction causes a rare but clinically significant inborn error of metabolism with neurological and congenital features. Additionally, the enzyme is a key determinant of fluoropyrimidine drug metabolism, influencing both toxicity and efficacy of 5-fluorouracil-based chemotherapy. Understanding its catalytic mechanism and regulation also provides insights into amidohydrolase superfamily enzymology and allosteric control.
• Completes pyrimidine catabolism, linking uracil and thymine degradation to beta-alanine production.
• Deficiency causes beta-ureidopropionase deficiency, an autosomal recessive disorder with neurological abnormalities.
• Associated with congenital anomalies of the urogenital and colorectal systems.
• Modulates fluoropyrimidine chemotherapy metabolism and toxicity.
• Serves as a model for allosteric regulation in amidohydrolase enzymes.
• Enables newborn screening and metabolic diagnostics via metabolite profiling.
• Provides a target for functional validation of UPB1 variants of uncertain significance.
• Relevant to plant and bacterial pyrimidine metabolism, with functional overexpression demonstrated in E. coli.
• Contributes to understanding of drug-metabolizing enzyme pharmacogenomics.
• Supports development of CRISPR models for rare metabolic disease research.
Molecular Mechanism of beta-ureidopropionase activity
Substrate recognition and binding
In simple terms: The enzyme grabs N-carbamoyl-beta-alanine and positions it for chemical breakdown.
Beta-ureidopropionase binds its substrate N-carbamoyl-beta-alanine in a metal-dependent active site. Structural and biochemical studies have shown that the enzyme belongs to the amidohydrolase superfamily and requires divalent metal ions for catalysis. The active site is formed by loops that must be precisely positioned for substrate binding and turnover.
Catalytic hydrolysis
In simple terms: A water molecule splits the substrate into beta-alanine, ammonia, and CO2.
The catalytic mechanism involves hydrolysis of the carbon-nitrogen bond in N-carbamoyl-beta-alanine, yielding beta-alanine, ammonia, and carbon dioxide. This reaction is the final step of pyrimidine degradation, following the actions of dihydropyrimidine dehydrogenase and dihydropyrimidinase. The enzyme also exhibits N-carbamoyl-alpha-L-amino acid amidohydrolase activity in some organisms.
Allosteric regulation
In simple terms: The enzyme can be switched on or off by molecules binding away from the active site.
Beta-ureidopropionase is allosterically regulated, and this regulation depends on the fine-tuned stability of active-site loops and subunit interfaces. Mutations that alter these structural elements can affect catalytic activity and allosteric response. This regulatory mechanism is critical for matching enzyme activity to metabolic demand.
Role in pyrimidine degradation pathway
In simple terms: It is the last step in breaking down uracil and thymine.
In the pyrimidine degradation pathway, beta-ureidopropionase catalyzes the conversion of N-carbamoyl-beta-alanine to beta-alanine, ammonia, and CO2. This step follows dihydropyrimidine dehydrogenase and dihydropyrimidinase, completing the catabolism of uracil and thymine. The pathway is conserved from bacteria to plants and humans, with functional homologs characterized in Pseudomonas putida and plants.
Clinical and pharmacological significance
In simple terms: The enzyme affects how the body handles certain chemotherapy drugs.
Beta-ureidopropionase activity is directly involved in the metabolism of fluoropyrimidine drugs such as 5-fluorouracil, influencing drug activation and detoxification. In vitro assessments of fluoropyrimidine-metabolizing enzymes, including beta-ureidopropionase, are used to predict patient responses and toxicity. Deficiency of the enzyme leads to accumulation of N-carbamoyl-beta-alanine, which can be detected by HPLC-electrospray tandem mass spectrometry.
Key Genes Involved in GO:0003837 beta-ureidopropionase activity
The following genes and proteins are directly associated with beta-ureidopropionase activity, its regulation, and its metabolic pathway.
| Gene | Major Role | Research Relevance |
|---|---|---|
| UPB1 | Encodes beta-ureidopropionase, the enzyme catalyzing the final step of pyrimidine degradation | Mutations cause beta-ureidopropionase deficiency; target for functional validation |
| DPYD | Encodes dihydropyrimidine dehydrogenase, the first enzyme in pyrimidine degradation | Pharmacogenomic marker for fluoropyrimidine toxicity |
| DPYS | Encodes dihydropyrimidinase, the second enzyme in pyrimidine degradation | Deficiency causes dihydropyrimidinuria; relevant to drug metabolism |
| UPB1 (splice variants) | Novel and rare mutations affect pre-mRNA splicing and protein structure | Splicing assays and structural modeling for variant interpretation |
| UPB1 (allosteric sites) | Mutations alter active-site loop stability and subunit interfaces | Allosteric regulation studies and protein engineering |
| Pseudomonas putida beta-ureidopropionase | Bacterial homolog with N-carbamoyl-alpha-L-amino acid amidohydrolase activity | Model for enzyme evolution and biocatalysis |
| Plant beta-ureidopropionase | Functional overexpression in E. coli demonstrates plant enzyme activity | Plant pyrimidine metabolism and biotechnology |
| Beta-alanine metabolic enzymes | Beta-alanine is the product of beta-ureidopropionase | Downstream metabolic and physiological studies |
| Ammonia detoxification enzymes | Ammonia is a product of the reaction | Links to nitrogen metabolism and hyperammonemia research |
| CO2-producing enzymes | CO2 is a product of the reaction | Carbon flux and metabolic labeling studies |
| N-carbamoyl-beta-alanine transporters | Transport of substrate and product | Metabolite profiling and transport assays |
| Fluoropyrimidine metabolizing enzymes | Coordinate with beta-ureidopropionase in drug metabolism | Pharmacogenomics and chemotherapy response |
| UPB1 regulatory variants | May affect enzyme expression or activity | CRISPR knock-in of variants for functional studies |
| Metal-binding residues in UPB1 | Required for catalytic activity | Mutagenesis and metal reconstitution studies |
| Active-site loop residues | Determine substrate specificity and allostery | Structural biology and molecular dynamics |
| Subunit interface residues | Mediate allosteric regulation | Protein-protein interaction studies |
| UPB1 promoter elements | Regulate UPB1 transcription | Reporter assays and CRISPR interference |
| UPB1 3'UTR elements | May regulate mRNA stability | RNA-binding protein studies |
How Is beta-ureidopropionase activity Regulated?
Beta-ureidopropionase activity is regulated at multiple levels. Allosteric regulation depends on the fine-tuned stability of active-site loops and subunit interfaces, as demonstrated by structural and biochemical studies. Mutations that destabilize these regions can alter catalytic activity and allosteric responses. Additionally, pre-mRNA splicing regulation affects UPB1 expression, with novel and rare mutations impacting splicing and protein integrity. At the pathway level, beta-ureidopropionase activity is coordinated with dihydropyrimidine dehydrogenase and dihydropyrimidinase to maintain pyrimidine homeostasis. Pharmacological regulation by fluoropyrimidine drugs can also influence enzyme activity and pathway flux.
beta-ureidopropionase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| UPB1 | Beta-ureidopropionase deficiency with neurological abnormalities | UPB1 knockout cell lines and patient-derived fibroblasts |
| UPB1 | Congenital anomalies of urogenital and colorectal systems | UPB1 knockout mouse models and organoids |
| UPB1 | Fluoropyrimidine chemotherapy toxicity | Isogenic cell lines with UPB1 point mutations |
| UPB1 | Splicing defects and protein instability | Minigene splicing assays and CRISPR knock-in of splice variants |
| UPB1 | Allosteric regulation defects | Recombinant protein expression and mutagenesis |
Beta-ureidopropionase deficiency
Beta-ureidopropionase deficiency is an autosomal recessive inborn error of pyrimidine degradation caused by biallelic mutations in UPB1. Patients present with a wide range of neurological abnormalities, including developmental delay, seizures, and hypotonia. The diagnosis is confirmed by detecting elevated N-carbamoyl-beta-alanine and related metabolites in body fluids using HPLC-electrospray tandem mass spectrometry. Novel and rare UPB1 mutations can affect pre-mRNA splicing and protein structural integrity, leading to reduced catalytic activity.
Congenital anomalies
Beta-ureidopropionase deficiency can present with congenital anomalies of the urogenital and colorectal systems, expanding the clinical phenotype beyond neurological symptoms. This suggests that pyrimidine degradation is important for normal embryonic development of these structures. Genetic diagnosis and functional studies of UPB1 variants are essential for understanding the developmental mechanisms.
Fluoropyrimidine chemotherapy toxicity
Beta-ureidopropionase activity is part of the fluoropyrimidine metabolic pathway, and altered enzyme activity can influence the balance between drug activation and detoxification. In vitro assessment of fluoropyrimidine-metabolizing enzymes, including beta-ureidopropionase, is used to predict patient responses and toxicity. Pharmacogenomic variants in UPB1 may therefore contribute to interindividual variability in chemotherapy outcomes.
Cancer biology
Pyrimidine degradation enzymes, including beta-ureidopropionase, are studied in cancer biology because of their role in nucleotide homeostasis and drug metabolism. Targeting pyrimidine catabolism may modulate sensitivity to antimetabolite drugs. However, direct evidence for beta-ureidopropionase as a cancer driver is limited, and further research is needed.
From beta-ureidopropionase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does UPB1 loss cause metabolic accumulation? | UPB1 knockout cell lines (e.g., HEK293, HepG2) |
| Do patient variants affect enzyme activity? | Point-mutation knock-in of UPB1 variants |
| Does a specific UPB1 isoform rescue deficiency? | Knock-in of tagged UPB1 isoforms |
| Can UPB1 overexpression enhance drug metabolism? | UPB1 overexpression cell lines |
| What is the role of allosteric sites in UPB1? | Site-directed mutagenesis and knock-in of allosteric mutants |
| How does UPB1 deficiency affect development? | UPB1 knockout zebrafish or mouse models |
How to Study the beta-ureidopropionase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC-ESI-MS/MS | Metabolite levels (N-carbamoyl-beta-alanine, beta-alanine) | Diagnosis of beta-ureidopropionase deficiency |
| Enzyme activity assay | Catalytic conversion of substrate to products | Functional validation of UPB1 variants |
| Minigene splicing assay | Pre-mRNA splicing patterns | Assessment of splice-site mutations |
| Western blot | Protein expression and stability | Evaluation of UPB1 protein levels |
| X-ray crystallography | Three-dimensional protein structure | Active-site and allosteric site mapping |
| Molecular dynamics | Protein dynamics and loop stability | Allosteric regulation studies |
| CRISPR knockout | Gene function loss | Phenotypic analysis of UPB1 deficiency |
| CRISPR knock-in | Specific variant introduction | Modeling patient mutations |
Metabolite profiling by HPLC-ESI-MS/MS
HPLC-electrospray tandem mass spectrometry is used to detect and quantify N-carbamoyl-beta-alanine and other pyrimidine metabolites in urine, plasma, or cell culture media. This method confirms beta-ureidopropionase deficiency at the metabolite level and is suitable for newborn screening and follow-up.
Enzyme activity assays
In vitro enzyme activity assays using recombinant beta-ureidopropionase or cell lysates measure the conversion of N-carbamoyl-beta-alanine to beta-alanine, ammonia, and CO2. These assays are used to assess the impact of UPB1 mutations on catalytic activity and to screen for inhibitors or activators.
Splicing assays
Minigene splicing assays and RT-PCR are used to evaluate the effect of UPB1 mutations on pre-mRNA splicing. Novel and rare UPB1 mutations affecting splicing can be functionally characterized using these methods.
Structural and biophysical methods
X-ray crystallography, cryo-EM, and molecular dynamics simulations are used to study the structure of beta-ureidopropionase, including active-site loops and subunit interfaces. These methods reveal how allosteric regulation depends on fine-tuned stability.
How CRISPR Can Be Used to Study GO:0003837 beta-ureidopropionase activity
Knockout
CRISPR knockout of UPB1 in human cell lines (e.g., HEK293, HepG2) creates isogenic models of beta-ureidopropionase deficiency. These models are used to study metabolite accumulation, pathway flux, and cellular responses to pyrimidine stress. Knockout cells can also be used to assess fluoropyrimidine sensitivity.
Point Mutation
CRISPR point mutation is used to introduce specific patient-associated UPB1 variants, such as missense mutations that affect catalytic activity or allosteric regulation. These models allow precise functional assessment of variants of uncertain significance. Point mutations in active-site or subunit interface residues can reveal structure-function relationships.
Knock-in
CRISPR knock-in can be used to insert tagged UPB1 alleles (e.g., FLAG, GFP) for localization, interaction, and stability studies. Knock-in of splice variants or regulatory elements helps dissect isoform-specific functions. This approach is valuable for creating reporter cell lines to monitor UPB1 expression.
Overexpression
CRISPR activation or lentiviral overexpression of UPB1 is used to study the effects of increased beta-ureidopropionase activity on pyrimidine metabolism and drug response. Overexpression models can rescue deficiency phenotypes and test gain-of-function hypotheses. They are also useful for producing recombinant enzyme for biochemical assays.
How EDITGENE Supports beta-ureidopropionase activity Research
Researchers studying beta-ureidopropionase activity-related genes often need to determine whether a candidate gene is causally involved in pyrimidine metabolism, drug response, or disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling functional validation of UPB1 variants and pathway components.
Contact EDITGENE today to design your custom CRISPR model for beta-ureidopropionase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| UPB1 Knockout HEK293 Cell Line | EDJ-KQ11206 | Human | 51733 | Details Get a Quote |
| UPB1 Knockout HeLa Cell Line | EDJ-KQ56354 | Human | 51733 | Details Get a Quote |
| UPB1 Knockout A-549 Cell Line | EDJ-KQ64844 | Human | 51733 | Details Get a Quote |
| UPB1 Knockout HCT 116 Cell Line | EDJ-KQ73288 | Human | 51733 | Details Get a Quote |
Frequently Asked Questions About beta-ureidopropionase activity
What is beta-ureidopropionase activity?
Beta-ureidopropionase activity (GO:0003837) is the catalytic function that converts N-carbamoyl-beta-alanine to beta-alanine, ammonia, and CO2, completing pyrimidine degradation.
What gene encodes beta-ureidopropionase in humans?
The UPB1 gene encodes beta-ureidopropionase in humans.
What diseases are associated with beta-ureidopropionase deficiency?
Beta-ureidopropionase deficiency causes neurological abnormalities and can present with congenital anomalies of the urogenital and colorectal systems.
How is beta-ureidopropionase deficiency diagnosed?
It is diagnosed by detecting elevated N-carbamoyl-beta-alanine and related metabolites using HPLC-electrospray tandem mass spectrometry.
What is the role of beta-ureidopropionase in cancer chemotherapy?
It participates in fluoropyrimidine metabolism, influencing the activation and detoxification of drugs like 5-fluorouracil.
Is beta-ureidopropionase allosterically regulated?
Yes, its activity is allosterically regulated through the stability of active-site loops and subunit interfaces.
What are the products of the beta-ureidopropionase reaction?
The products are beta-alanine, ammonia, and carbon dioxide.
Can CRISPR be used to study beta-ureidopropionase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are used to study UPB1 function and disease variants.
What is the pathway context of beta-ureidopropionase?
It is the third and final step in pyrimidine degradation, following dihydropyrimidine dehydrogenase and dihydropyrimidinase.
Are there animal models of beta-ureidopropionase deficiency?
Research models include UPB1 knockout cell lines and potentially mouse or zebrafish models to study developmental and neurological phenotypes.
Conclusion
Beta-ureidopropionase activity (GO:0003837) is a critical molecular function in pyrimidine catabolism, with direct implications for inherited metabolic disease and fluoropyrimidine chemotherapy. The UPB1 gene encodes the human enzyme, and its mutations cause beta-ureidopropionase deficiency, a disorder with neurological and congenital features. Allosteric regulation and structural integrity of active-site loops are key determinants of enzyme activity. CRISPR-based models are powerful tools for functional validation of UPB1 variants and for dissecting pathway biology. Continued research will improve diagnosis, genetic counseling, and personalized use of fluoropyrimidine drugs.
References
- 1. Dobritzsch D et al.. 2022. β-Ureidopropionase deficiency due to novel and rare UPB1 mutations affecting pre-mRNA splicing and protein structural integrity and catalytic activity.. Mol Genet Metab 136(3):177-185 PMID: 35151535
- 2. Cederfelt D et al.. 2023. The Allosteric Regulation of Β-Ureidopropionase Depends on Fine-Tuned Stability of Active-Site Loops and Subunit Interfaces.. Biomolecules 13(12) PMID: 38136634
- 3. Ogawa J et al.. 1994. Beta-ureidopropionase with N-carbamoyl-alpha-L-amino acid amidohydrolase activity from an aerobic bacterium, Pseudomonas putida IFO 12996.. Eur J Biochem 223(2):625-30 PMID: 8055933
- 4. Hishinuma E et al.. 2020. In Vitro Assessment of Fluoropyrimidine-Metabolizing Enzymes: Dihydropyrimidine Dehydrogenase, Dihydropyrimidinase, and β-Ureidopropionase.. J Clin Med 9(8) PMID: 32707991
- 5. van Kuilenburg AB et al.. 2004. beta-Ureidopropionase deficiency: an inborn error of pyrimidine degradation associated with neurological abnormalities.. Hum Mol Genet 13(22):2793-801 PMID: 15385443
- 6. Walsh TA et al.. 2001. Characterization of plant beta-ureidopropionase and functional overexpression in Escherichia coli.. Plant Physiol 125(2):1001-11 PMID: 11161056
- 7. Van Kuilenburg AB et al.. 2001. Detection of beta-ureidopropionase deficiency with HPLC-electrospray tandem mass spectrometry and confirmation of the defect at the enzyme level.. J Inherit Metab Dis 24(7):725-32 PMID: 11804209
- 8. Yaplito-Lee J et al.. 2008. Beta-ureidopropionase deficiency presenting with congenital anomalies of the urogenital and colorectal systems.. Mol Genet Metab 93(2):190-4 PMID: 17964839
