GO:0033540 fatty acid beta-oxidation using acyl-CoA oxidase: Peroxisomal Lipid Catabolism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0033540 describes the peroxisomal fatty acid beta-oxidation pathway in which acyl-CoA oxidase (ACOX) catalyzes the initial oxidation of acyl-CoA to trans-2-enoyl-CoA, transferring electrons directly to oxygen and producing hydrogen peroxide.
• This pathway is distinct from mitochondrial beta-oxidation because it uses acyl-CoA oxidase rather than acyl-CoA dehydrogenase and is tightly regulated by PPARα.
• ACOX1 is the rate-limiting enzyme for peroxisomal beta-oxidation of straight-chain fatty acids, and its expression is controlled by PPARα in response to lipid-lowering drugs and environmental pollutants.
• Peroxisomal beta-oxidation produces acetyl-CoA that can inhibit autophagy and promote hepatic steatosis via mTORC1 activation.
• Liver ACOX1 activity regulates circulating lipid levels and adipose remodeling, linking peroxisomal oxidation to systemic metabolic health.
• Dysregulation of peroxisomal beta-oxidation is implicated in metabolic disorders, cancer, and cold-induced thermogenesis through peroxisome-derived lipids.
Description
GO:0033540, fatty acid beta-oxidation using acyl-CoA oxidase, is a biological process that defines the peroxisomal route of fatty acid breakdown. In this pathway, the first step converting an acyl-CoA to a trans-2-enoyl-CoA is catalyzed by acyl-CoA oxidase, and the electrons removed during oxidation are transferred directly to molecular oxygen, generating hydrogen peroxide that is subsequently cleaved by peroxisomal catalases. This mechanism contrasts with mitochondrial beta-oxidation, which uses acyl-CoA dehydrogenases and feeds electrons into the respiratory chain. The pathway shortens fatty acids by two carbons per cycle, releasing acetyl-CoA or propionyl-CoA when only two or three carbons remain. Researchers study GO:0033540 because it is central to lipid homeostasis, energy balance, and the cellular response to diverse metabolic stresses.
fatty acid beta-oxidation using acyl-CoA oxidase At A Glance
| GO ID | GO:0033540 |
|---|---|
| GO term | fatty acid beta-oxidation using acyl-CoA oxidase |
| Ontology | biological_process |
| Synonym | peroxisomal fatty acid beta-oxidation |
| Major function | Oxidation of acyl-CoA to trans-2-enoyl-CoA with electrons transferred directly to oxygen, producing H2O2 that is cleaved by peroxisomal catalases |
| Pathway location | Peroxisome |
| Key enzyme | Acyl-CoA oxidase (ACOX1, ACOX2, ACOX3) |
| End products | Acetyl-CoA or propionyl-CoA |
| Regulatory factor | PPARα |
What Is GO:0033540?
GO:0033540 is a fatty acid beta-oxidation pathway in which the initial step, the conversion of an acyl-CoA to a trans-2-enoyl-CoA, is catalyzed by acyl-CoA oxidase. The electrons removed by this oxidation pass directly to oxygen and produce hydrogen peroxide, which is cleaved by peroxisomal catalases. The pathway begins with the addition of coenzyme A to a fatty acid and ends when only two or three carbons remain, as acetyl-CoA or propionyl-CoA respectively.
Why Is fatty acid beta-oxidation using acyl-CoA oxidase Important in Cell Biology?
GO:0033540 is essential for understanding how cells oxidize fatty acids that cannot be handled by mitochondria, including very-long-chain fatty acids and branched-chain substrates. The pathway generates hydrogen peroxide and acetyl-CoA, which influence redox balance, autophagy, and lipogenesis. Its dysregulation has been linked to hepatic steatosis, obesity, cancer, and thermogenesis, making it a key area for metabolic disease research.
• Provides an alternative route for fatty acid oxidation when mitochondrial beta-oxidation is insufficient.
• Regulates hepatic lipid metabolism and circulating lipid levels through ACOX1 activity.
• Produces acetyl-CoA that inhibits autophagy and promotes steatosis via mTORC1 activation.
• Generates peroxisome-derived lipids that mediate cold-induced mitochondrial fission and thermogenesis.
• Is a target of PPARα signaling, linking lipid-lowering drugs and environmental pollutants to metabolic outcomes.
• Contributes to colorectal cancer suppression through PTPRO-mediated reprogramming of fatty acid metabolism.
• Metabolizes branched fatty acids to regulate energy homeostasis.
• Serves as a biomarker and therapeutic target for hepatic lipid disorders.
What Happens During fatty acid beta-oxidation using acyl-CoA oxidase?
Activation and Import of Acyl-CoA
In simple terms: Fatty acids are first attached to coenzyme A and then transported into peroxisomes to start breakdown.
Fatty acid beta-oxidation begins with the addition of coenzyme A to a fatty acid, forming acyl-CoA. In peroxisomes, this step is followed by the import of acyl-CoA or its precursors through peroxisomal membrane transporters. The pathway is distinct from mitochondrial beta-oxidation because it uses acyl-CoA oxidase rather than acyl-CoA dehydrogenase for the initial oxidation.
Oxidation by Acyl-CoA Oxidase
In simple terms: Acyl-CoA oxidase removes electrons from acyl-CoA and hands them directly to oxygen, making hydrogen peroxide.
The defining step of GO:0033540 is the conversion of acyl-CoA to trans-2-enoyl-CoA by acyl-CoA oxidase. The electrons removed during this oxidation pass directly to molecular oxygen, producing hydrogen peroxide. This reaction is the rate-limiting step for peroxisomal beta-oxidation of straight-chain fatty acids and is catalyzed by ACOX1, with ACOX2 and ACOX3 handling branched-chain and other substrates.
Cleavage by Catalase and Chain Shortening
In simple terms: The hydrogen peroxide is broken down by catalase, and the fatty acid chain is shortened by two carbons per cycle.
Hydrogen peroxide generated by acyl-CoA oxidase is cleaved by peroxisomal catalases to protect the cell from oxidative damage. The trans-2-enoyl-CoA produced is then hydrated and further oxidized in subsequent steps, shortening the fatty acid chain by two carbons per cycle. The pathway ends when only two or three carbons remain, as acetyl-CoA or propionyl-CoA respectively.
Regulation by PPARα
In simple terms: PPARα acts as a master switch that turns up peroxisomal beta-oxidation genes when fatty acids are abundant.
Peroxisomal fatty acid beta-oxidation is regulated by PPARα, a nuclear receptor that controls the expression of genes including ACOX1. Activation of PPARα by ligands such as fibrates or environmental pollutants increases the capacity for peroxisomal beta-oxidation, linking this pathway to lipid-lowering responses and metabolic disorders.
Metabolic Outputs and Signaling
In simple terms: The breakdown products of peroxisomal beta-oxidation send signals that affect autophagy, fat storage, and energy use.
Acetyl-CoA derived from hepatic peroxisomal beta-oxidation inhibits autophagy and promotes steatosis via mTORC1 activation. Peroxisome-derived lipids regulate adipose thermogenesis by mediating cold-induced mitochondrial fission. Liver ACOX1 activity also regulates levels of circulating lipids that promote metabolic health through adipose remodeling. These outputs connect GO:0033540 to systemic energy homeostasis and metabolic disease.
Key Genes Involved in GO:0033540 fatty acid beta-oxidation using acyl-CoA oxidase
The following genes and proteins are central to the function, regulation, and study of GO:0033540.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACOX1 | Rate-limiting acyl-CoA oxidase for straight-chain fatty acids in peroxisomal beta-oxidation | Target for hepatic lipid disorders and metabolic studies |
| ACOX2 | Acyl-CoA oxidase for branched-chain fatty acids | Branched fatty acid metabolism and energy homeostasis |
| ACOX3 | Acyl-CoA oxidase with broad substrate specificity | Peroxisomal beta-oxidation of diverse substrates |
| PPARα | Nuclear receptor regulating ACOX1 and other beta-oxidation genes | Master regulator of peroxisomal beta-oxidation |
| CAT | Catalase that cleaves hydrogen peroxide produced by acyl-CoA oxidase | Redox protection in peroxisomes |
| PTPRO | Represses colorectal cancer by reprogramming fatty acid metabolism | Links peroxisomal oxidation to cancer suppression |
| mTORC1 | Signaling complex inhibited by acetyl-CoA from peroxisomal beta-oxidation | Autophagy and steatosis regulation |
| UCP1 | Uncoupling protein in thermogenesis, influenced by peroxisome-derived lipids | Adipose thermogenesis and cold response |
| DRP1 | Mitochondrial fission mediator regulated by peroxisome-derived lipids | Cold-induced mitochondrial dynamics |
| HMG-CoA synthase | Peroxisomal enzyme in cholesterol synthesis linked to beta-oxidation | Lipid metabolism integration |
| Thiolase | Cleaves 3-ketoacyl-CoA in peroxisomal beta-oxidation | Chain shortening and acetyl-CoA production |
| Bifunctional enzyme | Hydratase and dehydrogenase activities in peroxisomal beta-oxidation | Pathway completion |
| Carnitine acyltransferase | Transports acyl groups into peroxisomes | Substrate import for beta-oxidation |
| SLC25A17 | Peroxisomal membrane transporter for CoA and metabolites | Peroxisomal substrate supply |
| PEX genes | Peroxisome biogenesis and import machinery | Peroxisomal function and disease models |
| FATP | Fatty acid transport proteins | Substrate delivery to peroxisomes |
| LXR | Nuclear receptor influencing lipid metabolism | Cross-talk with peroxisomal beta-oxidation |
| SREBP | Transcription factor regulating lipogenic genes | Integration with peroxisomal lipid metabolism |
How Is fatty acid beta-oxidation using acyl-CoA oxidase Regulated?
GO:0033540 is primarily regulated at the transcriptional level by PPARα, which controls the expression of ACOX1 and other peroxisomal beta-oxidation genes in response to fatty acids, fibrates, and environmental pollutants. Post-translational regulation includes the availability of substrates and cofactors, as well as the redox balance maintained by catalase. Acetyl-CoA produced by the pathway can inhibit autophagy and promote steatosis via mTORC1 activation, providing a feedback link between peroxisomal beta-oxidation and cellular nutrient sensing. Liver ACOX1 activity also regulates circulating lipids that influence adipose remodeling, indicating systemic regulation of this pathway.
fatty acid beta-oxidation using acyl-CoA oxidase and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACOX1 | Hepatic lipid metabolism disorders, steatosis | Liver-specific ACOX1 knockout mouse |
| PPARα | Lipid disorders, environmental pollutant response | PPARα knockout or overexpression models |
| PTPRO | Colorectal cancer | PTPRO knockout cancer cell lines |
| ACOX2 | Branched fatty acid metabolism, energy homeostasis | ACOX2 knockout mouse |
| DRP1 | Cold-induced thermogenesis | Adipose-specific DRP1 knockout |
Metabolic Disorders and Hepatic Steatosis
Peroxisomal beta-oxidation using acyl-CoA oxidase is directly implicated in hepatic lipid metabolism disorders. PPARα/ACOX1 has been identified as a novel target for hepatic lipid metabolism disorders induced by per- and polyfluoroalkyl substances, linking environmental exposures to disrupted peroxisomal oxidation. Acetyl-CoA derived from hepatic peroxisomal beta-oxidation inhibits autophagy and promotes steatosis via mTORC1 activation, suggesting that overactive peroxisomal oxidation can contribute to fatty liver disease. Liver ACOX1 regulates levels of circulating lipids that promote metabolic health through adipose remodeling, indicating that its dysregulation may affect systemic lipid homeostasis.
Cancer
PTPRO represses colorectal cancer tumorigenesis and progression by reprogramming fatty acid metabolism, a process that involves peroxisomal beta-oxidation. This suggests that GO:0033540 can influence cancer cell metabolism and that its modulation may have therapeutic potential in colorectal cancer.
Thermogenesis and Energy Homeostasis
Peroxisome-derived lipids regulate adipose thermogenesis by mediating cold-induced mitochondrial fission, connecting GO:0033540 to energy expenditure. Peroxisomal metabolism of branched fatty acids regulates energy homeostasis, further highlighting the role of this pathway in systemic metabolic control.
From fatty acid beta-oxidation using acyl-CoA oxidase-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ACOX1 loss alter hepatic lipid accumulation? | ACOX1 knockout mouse or hepatocyte-specific KO |
| How does PPARα regulate ACOX1 expression? | PPARα knockout or agonist-treated cell models |
| Does peroxisomal beta-oxidation inhibit autophagy? | ACOX1 overexpression with mTORC1 readouts |
| What is the role of ACOX2 in branched fatty acid metabolism? | ACOX2 point-mutation or knockout models |
| How do peroxisome-derived lipids affect thermogenesis? | Adipose-specific knock-in of lipid-modifying enzymes |
| Can PTPRO reprogram fatty acid metabolism in cancer? | PTPRO knockout colorectal cancer cells |
How to Study the fatty acid beta-oxidation using acyl-CoA oxidase Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Gene expression changes in peroxisomal beta-oxidation genes | PPARα activation or pollutant exposure |
| Proteomics | Protein abundance of ACOX1 and related enzymes | Pathway validation in disease models |
| Lipidomics | Lipid species altered by peroxisomal beta-oxidation | Hepatic steatosis and circulating lipids |
| Metabolic flux analysis | Acetyl-CoA production from fatty acids | Autophagy and mTORC1 studies |
| Live-cell imaging | Peroxisome and mitochondrial dynamics | Cold-induced thermogenesis |
| CRISPR knockout | Loss-of-function effects on lipid metabolism | ACOX1, ACOX2, PPARα studies |
| Overexpression | Gain-of-function effects on beta-oxidation | Autophagy and steatosis models |
| Catalase activity assay | Hydrogen peroxide cleavage capacity | Redox balance in peroxisomes |
Transcriptomic and Proteomic Profiling
RNA-seq and proteomics can quantify expression of ACOX1, PPARα, and other genes in GO:0033540 across conditions such as PPARα activation or pollutant exposure. These methods help identify co-regulated pathways and biomarkers of peroxisomal beta-oxidation activity.
Metabolic Flux and Lipidomics
Lipidomics and metabolic flux analysis using labeled fatty acids can measure the contribution of peroxisomal beta-oxidation to acetyl-CoA production and circulating lipid levels. Such approaches are essential for linking GO:0033540 to steatosis and adipose remodeling.
Imaging and Organelle Dynamics
Live-cell imaging of peroxisomes and mitochondria can reveal how peroxisome-derived lipids mediate cold-induced mitochondrial fission. Fluorescent reporters for hydrogen peroxide or catalase activity can assess redox balance within peroxisomes.
Genetic and Pharmacological Perturbation
CRISPR knockout or overexpression of ACOX1, ACOX2, and PPARα in cell and animal models allows causal testing of GO:0033540 in metabolic disease. Pharmacological agonists or antagonists of PPARα can complement genetic studies.
How CRISPR Can Be Used to Study GO:0033540 fatty acid beta-oxidation using acyl-CoA oxidase
Knockout
CRISPR knockout of ACOX1, ACOX2, or PPARα can abolish peroxisomal beta-oxidation and reveal its role in hepatic lipid accumulation, autophagy, and energy homeostasis. Knockout models are essential for testing causality in metabolic disease.
Point Mutation
Point mutations in ACOX1 or PPARα can dissect catalytic residues or regulatory phosphorylation sites without fully eliminating protein expression. Such models help distinguish enzymatic activity from scaffolding functions in GO:0033540.
Knock-in
Knock-in of tagged ACOX1 or fluorescent reporters allows real-time tracking of peroxisomal beta-oxidation in live cells. This approach can map substrate specificity and organelle dynamics.
Overexpression
Overexpression of ACOX1 or PPARα can enhance peroxisomal beta-oxidation, leading to increased acetyl-CoA production and mTORC1 activation. This model is useful for studying steatosis and autophagy inhibition.
How EDITGENE Supports fatty acid beta-oxidation using acyl-CoA oxidase Research
Researchers studying fatty acid beta-oxidation using acyl-CoA oxidase-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, metabolic disease, or cancer. EDITGENE provides CRISPR-based cell models and screening services to accelerate this discovery process.
Contact EDITGENE today to design your custom CRISPR model for fatty acid beta-oxidation using acyl-CoA oxidase research.
Frequently Asked Questions About fatty acid beta-oxidation using acyl-CoA oxidase
What is GO:0033540?
GO:0033540 is the biological process of fatty acid beta-oxidation using acyl-CoA oxidase, in which acyl-CoA oxidase catalyzes the initial oxidation step and electrons are transferred directly to oxygen, producing hydrogen peroxide.
What genes are involved in fatty acid beta-oxidation using acyl-CoA oxidase?
Key genes include ACOX1, ACOX2, ACOX3, PPARα, CAT, and PTPRO, among others.
Where does peroxisomal fatty acid beta-oxidation occur?
It occurs in peroxisomes, where acyl-CoA oxidase and catalase are localized.
How is peroxisomal beta-oxidation regulated?
It is primarily regulated by PPARα, which controls the expression of ACOX1 and other beta-oxidation genes.
What is the difference between peroxisomal and mitochondrial beta-oxidation?
Peroxisomal beta-oxidation uses acyl-CoA oxidase and transfers electrons directly to oxygen, while mitochondrial beta-oxidation uses acyl-CoA dehydrogenase and feeds electrons into the respiratory chain.
What diseases are linked to peroxisomal beta-oxidation?
It is linked to hepatic steatosis, metabolic disorders, colorectal cancer, and thermogenesis defects.
How can I study GO:0033540 in the lab?
Common methods include RNA-seq, lipidomics, metabolic flux analysis, live-cell imaging, and CRISPR knockout or overexpression models.
What is the role of ACOX1 in liver metabolism?
ACOX1 regulates circulating lipids and hepatic lipid levels, and its activity influences adipose remodeling and metabolic health.
Does peroxisomal beta-oxidation affect autophagy?
Yes, acetyl-CoA derived from hepatic peroxisomal beta-oxidation inhibits autophagy and promotes steatosis via mTORC1 activation.
What are the end products of peroxisomal beta-oxidation?
The pathway ends when only two or three carbons remain, as acetyl-CoA or propionyl-CoA respectively.
Conclusion
GO:0033540, fatty acid beta-oxidation using acyl-CoA oxidase, is a fundamental peroxisomal pathway that governs lipid breakdown, energy homeostasis, and cellular redox balance. Its unique enzymatic mechanism and regulation by PPARα make it a critical node in metabolic disease, cancer, and thermogenesis research. Understanding this pathway through CRISPR models and multi-omics approaches will continue to reveal therapeutic opportunities for metabolic disorders.
References
- 1. Tahri-Joutey M et al.. 2021. Mechanisms Mediating the Regulation of Peroxisomal Fatty Acid Beta-Oxidation by PPARα.. Int J Mol Sci 22(16) PMID: 34445672
- 2. Dai W et al.. 2022. PTPRO represses colorectal cancer tumorigenesis and progression by reprogramming fatty acid metabolism.. Cancer Commun (Lond) 42(9):848-867 PMID: 35904817
- 3. Yang W et al.. 2023. PPARα/ACOX1 as a novel target for hepatic lipid metabolism disorders induced by per- and polyfluoroalkyl substances: An integrated approach.. Environ Int 178:108138 PMID: 37572494
- 4. Liu X et al.. 2025. Peroxisomal metabolism of branched fatty acids regulates energy homeostasis.. Nature 646(8087):1223-1231 PMID: 40963015
- 5. He A et al.. 2020. Acetyl-CoA Derived from Hepatic Peroxisomal β-Oxidation Inhibits Autophagy and Promotes Steatosis via mTORC1 Activation.. Mol Cell 79(1):30-42.e4 PMID: 32473093
- 6. Park H et al.. 2019. Peroxisome-derived lipids regulate adipose thermogenesis by mediating cold-induced mitochondrial fission.. J Clin Invest 129(2):694-711 PMID: 30511960
- 7. Lu D et al.. 2024. Liver ACOX1 regulates levels of circulating lipids that promote metabolic health through adipose remodeling.. Nat Commun 15(1):4214 PMID: 38760332
- 8. Mannaerts GP et al.. 1993. [Peroxisomal beta-oxidation].. Verh K Acad Geneeskd Belg 55(1):45-78 PMID: 8480447
