GO:0008391 arachidonate monooxygenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008391 arachidonate monooxygenase activity is a molecular function that inserts one oxygen atom from O2 into arachidonic acid while reducing the other to water.
• Cytochrome P450 enzymes, especially CYP4A and CYP4F subfamily members, are the principal catalysts annotated to this activity.
• The reaction produces hydroxylated eicosanoids such as 20-HETE, which regulate vascular tone and inflammation.
• Aspirin and other NSAIDs indirectly modulate arachidonate metabolism by acetylating prostaglandin synthase, shifting flux toward monooxygenase pathways.
• Dysregulated arachidonate monooxygenase activity is linked to asthma, cardiovascular disease, and cancer.
• CRISPR knockout, point mutation, and overexpression models are essential to dissect the role of CYP4 enzymes in eicosanoid biology.
Description
Arachidonate monooxygenase activity (GO:0008391) is a molecular function that catalyzes the incorporation of one atom of molecular oxygen into arachidonic acid, with the other oxygen atom reduced to water. This activity is a key branch of eicosanoid biosynthesis, distinct from cyclooxygenase and lipoxygenase pathways, and is primarily mediated by cytochrome P450 enzymes of the CYP4A and CYP4F subfamilies. The reaction yields hydroxylated metabolites, such as 20-hydroxyeicosatetraenoic acid (20-HETE), which act as lipid mediators in vascular, renal, and inflammatory processes. Researchers study this activity to understand how lipid signaling contributes to physiology and disease, and to develop therapeutic strategies targeting these enzymes. The availability of recombinant enzymes and CRISPR models has accelerated functional annotation of this GO term.
arachidonate monooxygenase activity At A Glance
| GO ID | GO:0008391 |
|---|---|
| GO term | arachidonate monooxygenase activity |
| Ontology | molecular_function |
| Synonym | arachidonic acid monooxygenase activity; cytochrome P450 CYP2B19 |
| Definition | Catalysis of the incorporation of one atom from molecular oxygen into arachidonic acid and the reduction of the other atom of oxygen to water. |
| Major function | Oxidation of arachidonic acid to hydroxylated eicosanoids, including 20-HETE. |
| Representative enzymes | CYP4A11, CYP4F2, CYP4F3, and related cytochrome P450 isoforms. |
| Substrate | Arachidonic acid (20:4, omega-6 polyunsaturated fatty acid). |
| Cofactor | NADPH and cytochrome P450 reductase for electron transfer. |
| Cellular location | Endoplasmic reticulum membrane. |
| Pathway context | Eicosanoid biosynthesis, lipid signaling, vascular homeostasis. |
What Is GO:0008391?
According to the Gene Ontology, arachidonate monooxygenase activity (GO:0008391) is defined as the catalysis of the incorporation of one atom from molecular oxygen into arachidonic acid and the reduction of the other atom of oxygen to water. In other words, it is an oxidation reaction that uses arachidonic acid as a substrate and molecular oxygen as a co-substrate, producing a hydroxylated fatty acid and water. This activity is a type of monooxygenase function and is synonymous with arachidonic acid monooxygenase activity and cytochrome P450 CYP2B19.
Why Is arachidonate monooxygenase activity Important in Cell Biology?
Arachidonate monooxygenase activity is important because it generates lipid mediators that control vascular tone, renal function, and inflammation. The enzymes catalyzing this activity, such as CYP4A and CYP4F isoforms, are drug targets and biomarkers in cardiovascular and respiratory diseases. Understanding this activity helps explain how nonsteroidal anti-inflammatory drugs like aspirin can shift arachidonic acid metabolism toward monooxygenase products, with clinical implications for aspirin sensitivity and asthma. Moreover, comparative studies in marine mammals have revealed evolutionary adaptations in eicosanoid biosynthesis that depend on this activity.
• Produces 20-HETE, a potent vasoconstrictor and regulator of blood pressure.
• Involved in the catabolism of leukotriene B4, a proinflammatory mediator.
• Modulates renal tubular function and sodium balance.
• Contributes to the pathogenesis of aspirin-exacerbated respiratory disease.
• Provides a route for arachidonic acid oxidation independent of cyclooxygenases.
• Serves as a target for antihypertensive and anti-inflammatory drug development.
• Shows species-specific differences in substrate specificity and regioselectivity.
• Plays a role in skin pigmentation pathways via related cytochrome P450 enzymes.
• Can be studied using recombinant expression in E. coli for enzyme kinetics.
• Links lipid metabolism to cancer cell proliferation and survival.
What Happens During arachidonate monooxygenase activity?
Substrate binding and oxygen activation
In simple terms: The enzyme grabs arachidonic acid and splits an oxygen molecule.
The catalytic cycle begins when arachidonic acid binds to the active site of a cytochrome P450 enzyme, such as CYP4A11 or CYP4F2. Molecular oxygen then binds to the heme iron, and electrons from NADPH via cytochrome P450 reductase reduce one oxygen atom to water while the other is inserted into the substrate. This monooxygenase mechanism is characteristic of GO:0008391 and distinguishes it from dioxygenases.
Hydroxylation and product release
In simple terms: The enzyme adds an OH group to arachidonic acid and releases the product.
The activated oxygen atom is incorporated into arachidonic acid, typically at the omega or omega-1 position, yielding 20-HETE or 19-HETE. These hydroxylated eicosanoids are released from the active site and can act on nearby cells or enter the circulation. The regioselectivity of hydroxylation varies among CYP4 isoforms, influencing the biological potency of the products.
Role in eicosanoid biosynthesis
In simple terms: This activity is one branch of the eicosanoid tree.
Arachidonate monooxygenase activity competes with cyclooxygenase and lipoxygenase pathways for arachidonic acid. When cyclooxygenase is inhibited by aspirin, flux can be redirected toward monooxygenase products, which may contribute to aspirin sensitivity. The balance between these pathways determines the overall eicosanoid profile in tissues.
Physiological and pathophysiological consequences
In simple terms: The products affect blood vessels and inflammation.
20-HETE produced by this activity constricts blood vessels and regulates renal sodium transport. In inflammation, CYP4F2 catabolizes leukotriene B4, thereby limiting proinflammatory signaling. Dysregulation of these enzymes has been observed in asthma, hypertension, and cancer, making this activity a research focus.
Key Genes Involved in GO:0008391 arachidonate monooxygenase activity
The following genes encode enzymes or related proteins that catalyze or modulate arachidonate monooxygenase activity (GO:0008391).
| Gene | Major Role | Research Relevance |
|---|---|---|
| CYP4A11 | Omega-hydroxylation of arachidonic acid to 20-HETE | Vascular tone regulation, hypertension models |
| CYP4F2 | Omega-hydroxylation and leukotriene B4 catabolism | Inflammation resolution, hepatic metabolism |
| CYP4F3 | Omega-hydroxylation of arachidonic acid and leukotriene B4 | Inflammatory diseases, drug metabolism |
| CYP4A22 | Fatty acid omega-hydroxylase | Renal and hepatic lipid signaling |
| CYP4B1 | Omega-hydroxylation of fatty acids | Xenobiotic metabolism, lung cancer |
| CYP2B19 | Arachidonic acid monooxygenase (synonym) | Skin barrier function, keratinocyte differentiation |
| CYP4F8 | Arachidonic acid omega-hydroxylase | Prostate cancer, inflammation |
| CYP4F11 | Omega-hydroxylation of fatty acids | Drug metabolism, fatty acid homeostasis |
| CYP4F12 | Arachidonic acid and eicosanoid metabolism | Asthma, allergic inflammation |
| CYP4A1 | Rodent omega-hydroxylase | Model for human CYP4A enzymes |
| CYP4A2 | Rodent omega-hydroxylase | Hypertension studies |
| CYP4A3 | Rodent omega-hydroxylase | Renal function studies |
| CYP4F1 | Rodent leukotriene B4 omega-hydroxylase | Inflammation models |
| CYP4F4 | Rodent arachidonic acid omega-hydroxylase | Lipid mediator research |
| CYP4F5 | Rodent omega-hydroxylase | Brain eicosanoid metabolism |
| CYP4F6 | Rodent omega-hydroxylase | Reproductive biology |
| PTGS1 | Prostaglandin synthase (cyclooxygenase-1) | Aspirin acetylation target, eicosanoid crosstalk |
How Is arachidonate monooxygenase activity Regulated?
Arachidonate monooxygenase activity is regulated at multiple levels. Enzyme expression is induced by peroxisome proliferator-activated receptor alpha (PPARα) and other nuclear receptors in response to fatty acids and xenobiotics. Post-translational modifications, such as phosphorylation, can modulate catalytic efficiency. Additionally, substrate availability and competition with cyclooxygenase and lipoxygenase pathways influence flux through this activity. In disease states, inflammatory cytokines can upregulate CYP4F enzymes, altering eicosanoid profiles.
arachidonate monooxygenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CYP4A11 | Hypertension, cardiovascular disease | Knockout rat or mouse, overexpression in vascular smooth muscle cells |
| CYP4F2 | Inflammation, leukotriene B4 catabolism | Knockout mouse, liver-specific overexpression |
| CYP4F3 | Asthma, aspirin sensitivity | Knock-in of human variant, airway epithelial cell model |
| CYP4F8 | Prostate cancer | Knockout prostate cancer cell line, xenograft model |
| CYP2B19 | Skin barrier function, pigmentation | Keratinocyte-specific knockout, point mutation |
Cardiovascular disease and hypertension
20-HETE produced by arachidonate monooxygenase activity is a potent vasoconstrictor and contributes to the regulation of blood pressure. Genetic variants in CYP4A11 and CYP4F2 have been associated with hypertension in human studies. Targeting this activity may offer therapeutic benefits for cardiovascular disorders.
Asthma and aspirin sensitivity
Aspirin-exacerbated respiratory disease involves a shift in arachidonic acid metabolism toward monooxygenase pathways, leading to increased production of proinflammatory eicosanoids. CYP4F enzymes are expressed in airway epithelium and may contribute to disease severity. Inhibitors of this activity are being explored for asthma treatment.
Inflammation and leukotriene catabolism
CYP4F2 and CYP4F3 catalyze the omega-hydroxylation of leukotriene B4, a key step in terminating its proinflammatory actions. Reduced activity of these enzymes can prolong inflammation and has been linked to chronic inflammatory diseases.
Cancer and cell proliferation
Arachidonate monooxygenase products, including 20-HETE, have been shown to promote angiogenesis and cancer cell proliferation in preclinical models. CYP4F8 and CYP4A11 are overexpressed in some tumors, suggesting a role in tumor progression. Inhibitors of this activity are being investigated as anticancer agents.
From arachidonate monooxygenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of CYP4A11 reduce 20-HETE production? | CRISPR knockout in human endothelial cells |
| Does a CYP4F2 point mutation alter leukotriene B4 catabolism? | Point mutation knock-in in HepG2 cells |
| Can overexpression of CYP4F8 promote tumor growth? | Overexpression in prostate cancer cell lines and mouse xenografts |
| What is the effect of CYP4A11 tagging on subcellular localization? | Tagged knock-in with GFP in renal epithelial cells |
| Does CYP4F3 knockout affect airway inflammation? | Knockout mouse model of asthma |
| Can CRISPR activation of CYP4A22 increase 20-HETE? | CRISPRa in hepatocytes |
How to Study the arachidonate monooxygenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS/MS | Hydroxylated arachidonic acid metabolites | Quantification of 20-HETE in plasma or tissues |
| HPLC-UV | Enzymatic conversion of arachidonic acid | In vitro enzyme kinetics |
| qRT-PCR | mRNA levels of CYP4 genes | Expression profiling in disease models |
| Western blot | Protein expression of CYP4 enzymes | Validation of knockout or overexpression |
| CRISPR knockout | Loss-of-function phenotypes | Identifying gene function in eicosanoid pathways |
| CRISPR activation | Gain-of-function phenotypes | Enhancing CYP4 expression for metabolic studies |
| Lipidomics | Global eicosanoid profile | Biomarker discovery in inflammation |
Enzyme activity assays
Recombinant CYP4 enzymes expressed in E. coli or insect cells can be used to measure arachidonate monooxygenase activity by monitoring the conversion of arachidonic acid to hydroxylated products using HPLC or LC-MS. These assays provide kinetic parameters and substrate specificity data.
Gene expression analysis
Quantitative RT-PCR and RNA-seq can quantify CYP4A and CYP4F mRNA levels in tissues or cell models. Western blotting with specific antibodies confirms protein expression.
Lipidomics and metabolomics
LC-MS/MS-based lipidomics enables comprehensive profiling of eicosanoids, including 20-HETE and other arachidonic acid metabolites, in biological samples. This approach is essential for linking enzyme activity to physiological outcomes.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout screens can identify genes that regulate arachidonate monooxygenase activity or its downstream effects. Such screens have revealed novel modulators of eicosanoid biosynthesis in cancer cells.
How CRISPR Can Be Used to Study GO:0008391 arachidonate monooxygenase activity
Knockout
CRISPR knockout of CYP4A11 or CYP4F2 in cell lines or animal models abolishes arachidonate monooxygenase activity, allowing researchers to study the consequences for eicosanoid production and downstream physiology. Knockout models are essential for validating the role of specific enzymes in disease.
Point Mutation
Introducing point mutations in the catalytic domain of CYP4 enzymes can dissect substrate binding and catalytic mechanism. For example, mutating the heme-binding cysteine residue abolishes monooxygenase activity, providing a negative control.
Knock-in
Knock-in of human CYP4 variants into mouse models can mimic human genetic polymorphisms associated with hypertension or asthma. Tagged knock-in with fluorescent proteins enables real-time imaging of enzyme localization and trafficking.
Overexpression
Overexpression of CYP4A or CYP4F enzymes in cell lines or transgenic animals increases arachidonate monooxygenase activity, facilitating studies on the effects of elevated 20-HETE or other metabolites. This approach is useful for drug screening and target validation.
How EDITGENE Supports arachidonate monooxygenase activity Research
Researchers studying arachidonate monooxygenase activity-related genes often need to determine whether a candidate gene is causally involved in eicosanoid biosynthesis, vascular tone, or inflammation. EDITGENE provides a comprehensive suite of CRISPR services to enable such functional studies with high precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for arachidonate monooxygenase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CYP1A1 Knockout HEK293 Cell Line | EDJ-KQ3897 | Human | 1543 | Details Get a Quote |
| CYP4A11 Knockout HEK293 Cell Line | EDJ-KQ4408 | Human | 1579 | Details Get a Quote |
| CYP4A22 Knockout HEK293 Cell Line | EDJ-KQ13074 | Human | 284541 | Details Get a Quote |
| CYP1A1 Knockout HCT 116 Cell Line | EDJ-KQ26114 | Human | 1543 | Details Get a Quote |
| CYP1A1 Knockout HeLa Cell Line | EDJ-KQ53039 | Human | 1543 | Details Get a Quote |
| CYP4A11 Knockout HeLa Cell Line | EDJ-KQ53054 | Human | 1579 | Details Get a Quote |
| CYP4A22 Knockout HeLa Cell Line | EDJ-KQ59479 | Human | 284541 | Details Get a Quote |
| CYP1A1 Knockout A-549 Cell Line | EDJ-KQ61503 | Human | 1543 | Details Get a Quote |
| CYP4A11 Knockout A-549 Cell Line | EDJ-KQ61519 | Human | 1579 | Details Get a Quote |
| CYP4A22 Knockout A-549 Cell Line | EDJ-KQ67945 | Human | 284541 | Details Get a Quote |
| CYP4A11 Knockout HCT 116 Cell Line | EDJ-KQ70011 | Human | 1579 | Details Get a Quote |
| CYP4A22 Knockout HCT 116 Cell Line | EDJ-KQ76325 | Human | 284541 | Details Get a Quote |
Displaying Records 1 To 12 Of 12 Records
Frequently Asked Questions About arachidonate monooxygenase activity
What is arachidonate monooxygenase activity?
Arachidonate monooxygenase activity (GO:0008391) is a molecular function that catalyzes the incorporation of one oxygen atom from molecular oxygen into arachidonic acid while reducing the other oxygen atom to water.
What genes are involved in arachidonate monooxygenase activity?
The main genes are cytochrome P450 family members, including CYP4A11, CYP4F2, CYP4F3, CYP4F8, and CYP2B19.
What is the role of CYP4A11 in arachidonate monooxygenase activity?
CYP4A11 catalyzes the omega-hydroxylation of arachidonic acid to produce 20-HETE, a vasoactive eicosanoid.
How is arachidonate monooxygenase activity regulated?
It is regulated by PPARα, substrate availability, and competition with cyclooxygenase and lipoxygenase pathways.
What diseases are associated with arachidonate monooxygenase activity?
It is linked to hypertension, asthma, inflammation, and cancer.
How can I study arachidonate monooxygenase activity in the lab?
Common methods include LC-MS/MS for metabolite quantification, qRT-PCR for gene expression, and CRISPR knockout for functional studies.
What is the difference between arachidonate monooxygenase and cyclooxygenase?
Cyclooxygenase produces prostaglandins, while arachidonate monooxygenase produces hydroxylated eicosanoids like 20-HETE; both compete for arachidonic acid.
Can CRISPR be used to study arachidonate monooxygenase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the function of CYP4 enzymes.
What is 20-HETE and how is it related to this activity?
20-HETE is a major product of arachidonate monooxygenase activity and acts as a vasoconstrictor and signaling molecule.
Which cell models are best for studying arachidonate monooxygenase activity?
Endothelial cells, hepatocytes, and renal epithelial cells are commonly used, and EDITGENE can provide customized CRISPR models for these cell types.
Conclusion
Arachidonate monooxygenase activity (GO:0008391) is a critical molecular function in eicosanoid biology, with far-reaching implications for vascular, inflammatory, and neoplastic diseases. The cytochrome P450 enzymes that catalyze this activity, such as CYP4A11 and CYP4F2, are promising therapeutic targets. Advances in CRISPR genome editing and lipidomics have accelerated our understanding of this pathway, and EDITGENE offers the tools and expertise to drive further discoveries.
References
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- 2. Jin R et al.. 1998. Role of human CYP4F2 in hepatic catabolism of the proinflammatory agent leukotriene B4.. Arch Biochem Biophys 359(1):89-98 PMID: 9799565
- 3. Hoch U et al.. 2000. Structural determination of the substrate specificities and regioselectivities of the rat and human fatty acid omega-hydroxylases.. Arch Biochem Biophys 373(1):63-71 PMID: 10620324
- 4. Palmer CN et al.. 1993. Characterization of a cDNA encoding a human kidney, cytochrome P-450 4A fatty acid omega-hydroxylase and the cognate enzyme expressed in Escherichia coli.. Biochim Biophys Acta 1172(1-2):161-6 PMID: 7679927
- 5. Reisch F et al.. 2021. Eicosanoid biosynthesis in marine mammals.. FEBS J 288(4):1387-1406 PMID: 32627384
- 6. Picado C. 2006. Mechanisms of aspirin sensitivity.. Curr Allergy Asthma Rep 6(3):198-202 PMID: 16579869
- 7. Fleming I. 2001. Cytochrome p450 and vascular homeostasis.. Circ Res 89(9):753-62 PMID: 11679404
- 8. Gilchrest BA et al.. 1996. Mechanisms of ultraviolet light-induced pigmentation.. Photochem Photobiol 63(1):1-10 PMID: 8577860
