GO:0120502 fatty acid omega-1 hydroxylase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0120502 defines fatty acid omega-1 hydroxylase activity, a cytochrome P450-dependent monooxygenase reaction that adds a hydroxyl group to the omega-1 carbon of fatty acids.
• The reaction consumes O2 and reduced NADPH--hemoprotein reductase and produces an (omega-1)-hydroxy fatty acid, H+, H2O, and oxidized NADPH--hemoprotein reductase.
• CYP4A and CYP4F subfamily enzymes are the principal mammalian proteins associated with fatty acid omega and omega-1 hydroxylation.
• This activity is best known for its role in generating 20-HETE from arachidonic acid, a lipid mediator that influences vascular tone and hypertension.
• Dysregulated omega-1 hydroxylation has been linked to metabolic dysfunction-associated steatotic liver disease, alcoholic liver disease, and hypertension-related target-organ fibrosis.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal testing of CYP4A/CYP4F genes in these disease contexts.
Description
GO:0120502, fatty acid omega-1 hydroxylase activity, is a molecular function that catalyzes the hydroxylation of a fatty acid at the carbon adjacent to the terminal methyl group, known as the omega-1 position. This reaction is carried out by cytochrome P450 enzymes, most notably members of the CYP4A and CYP4F subfamilies, and requires molecular oxygen and electrons supplied by NADPH--hemoprotein reductase. The term is distinct from omega hydroxylation, which targets the terminal methyl carbon, although many CYP4 enzymes can perform both reactions with overlapping substrate specificity. Researchers study this activity because its products, including (omega-1)-hydroxy fatty acids and downstream eicosanoids such as 20-HETE, act as signaling molecules in vascular, hepatic, and renal physiology. Altered omega-1 hydroxylase activity has been observed in experimental alcoholic liver disease and in metabolic dysfunction-associated steatotic liver disease, where CYP4 family expression correlates with disease progression. In hypertension models, inhibition or genetic manipulation of arachidonic acid omega-hydroxylase activity reduces blood pressure, highlighting the pathophysiological relevance of this enzyme class. The following sections integrate the QuickGO definition with published literature to provide a research-grade overview of GO:0120502, its genes, mechanisms, disease links, and experimental approaches.
fatty acid omega-1 hydroxylase activity At A Glance
| GO ID | GO:0120502 |
|---|---|
| GO term | fatty acid omega-1 hydroxylase activity |
| Ontology | molecular_function |
| Synonym | none |
| Major function | Catalyzes hydroxylation of fatty acids at the omega-1 carbon using O2 and reduced NADPH--hemoprotein reductase |
| Reaction | an (omega-1)-ethyl fatty acid + O2 + reduced [NADPH--hemoprotein reductase] = an (omega-1)-hydroxy fatty acid + H+ + H2O + oxidized [NADPH--hemoprotein reductase] |
| Representative enzymes | CYP4A and CYP4F subfamily cytochrome P450 enzymes |
| Substrates | Medium- and long-chain fatty acids, including arachidonic acid |
| Cofactors | O2 and NADPH--hemoprotein reductase |
What Is GO:0120502?
In our own words, GO:0120502 describes the catalytic activity of an enzyme that introduces a single hydroxyl group at the omega-1 carbon of a fatty acid substrate, using molecular oxygen and reducing equivalents from NADPH--hemoprotein reductase. The reaction converts an (omega-1)-ethyl fatty acid to an (omega-1)-hydroxy fatty acid, releasing H+, H2O, and oxidized NADPH--hemoprotein reductase. This activity is a subtype of fatty acid hydroxylation performed by cytochrome P450 monooxygenases and is distinguished from omega hydroxylation by the position of the hydroxyl group on the penultimate carbon of the acyl chain.
Why Is fatty acid omega-1 hydroxylase activity Important in Cell Biology?
Fatty acid omega-1 hydroxylase activity is important because it generates bioactive lipid mediators that regulate vascular tone, renal function, and hepatic lipid metabolism, and because its dysregulation is associated with major human diseases including hypertension, metabolic dysfunction-associated steatotic liver disease, and alcoholic liver disease. Understanding this activity at the molecular level helps researchers interpret how CYP4 enzymes contribute to disease progression and provides a basis for targeting these pathways experimentally.
• Produces (omega-1)-hydroxy fatty acids that can serve as precursors to signaling eicosanoids.
• Contributes to the biosynthesis of 20-HETE, a potent vasoactive lipid.
• Modulates blood pressure in experimental hypertension models.
• Is implicated in the progression of metabolic dysfunction-associated steatotic liver disease.
• Shows altered activity in experimental alcoholic liver disease depending on dietary fatty acids.
• Represents a cytochrome P450-dependent mechanism for fatty acid oxidation and hydroxylation.
• Provides a target for pharmacological inhibition to reduce 20-HETE overproduction.
• Helps explain inter-individual differences in fatty acid metabolism and disease susceptibility.
• Is conserved in plants, as shown by a promiscuous fatty acid omega-hydroxylase in loquat.
• Offers a molecular function for functional genomics and CRISPR-based validation.
What Happens During fatty acid omega-1 hydroxylase activity?
Substrate binding and oxygen activation
In simple terms: The enzyme grabs a fatty acid and activates oxygen so it can add a hydroxyl group.
The catalytic cycle begins when a fatty acid substrate binds to the active site of a cytochrome P450 enzyme, such as CYP4A or CYP4F family members. Molecular oxygen then binds to the heme iron, and electrons delivered by NADPH--hemoprotein reductase reduce the iron-oxygen complex, enabling cleavage of the O-O bond and formation of a reactive iron-oxo species. This step is common to P450 monooxygenases and is required for subsequent hydroxylation.
Regioselective hydroxylation at the omega-1 carbon
In simple terms: The activated oxygen is inserted at the second-to-last carbon of the fatty acid chain.
The reactive iron-oxo intermediate abstracts a hydrogen atom from the omega-1 carbon of the fatty acid, followed by oxygen rebound to form an (omega-1)-hydroxy fatty acid. The regioselectivity of this step distinguishes omega-1 hydroxylation from omega hydroxylation, although many CYP4 enzymes can catalyze both reactions to varying degrees. Substrate chain length and active-site geometry influence the ratio of omega to omega-1 products.
Product release and cofactor regeneration
In simple terms: The hydroxylated fatty acid is released, and the reductase is recycled.
After hydroxylation, the (omega-1)-hydroxy fatty acid product dissociates from the enzyme, along with H+ and H2O. The oxidized NADPH--hemoprotein reductase is regenerated by NADPH, allowing another round of catalysis. This coupling of P450 activity to the reductase ensures continuous electron supply for fatty acid hydroxylation.
Physiological context of omega-1 hydroxylation
In simple terms: This reaction happens in tissues like liver, kidney, and blood vessels, where its products act as signals.
In mammals, fatty acid omega-1 hydroxylase activity is prominent in the liver, kidney, and vasculature, where CYP4A and CYP4F enzymes are expressed. The products can be further metabolized to bioactive lipids such as 20-HETE, which modulates vascular tone and renal sodium transport. In plants, a promiscuous fatty acid omega-hydroxylase participates in the biosynthesis of floral nitro compounds, indicating broader biological roles for this activity.
Key Genes Involved in GO:0120502 fatty acid omega-1 hydroxylase activity
The following genes encode cytochrome P450 enzymes and associated proteins that catalyze or support fatty acid omega-1 hydroxylase activity, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CYP4A11 | Fatty acid omega and omega-1 hydroxylase; produces 20-HETE from arachidonic acid | Implicated in hypertension and liver disease |
| CYP4A22 | Fatty acid hydroxylase in humans | Studied in metabolic dysfunction-associated steatotic liver disease |
| CYP4A1 | Rodent fatty acid omega hydroxylase | Model for renal and vascular 20-HETE production |
| CYP4A2 | Rodent fatty acid omega hydroxylase | Used in experimental alcoholic liver disease studies |
| CYP4A3 | Rodent fatty acid omega hydroxylase | Investigated in hypertension models |
| CYP4F2 | Omega and omega-1 hydroxylase; vitamin K and fatty acid metabolism | Linked to hypertension and 20-HETE synthesis |
| CYP4F3 | Fatty acid omega hydroxylase; leukotriene B4 omega hydroxylation | Studied in inflammation and vascular biology |
| CYP4F8 | Arachidonic acid omega-1 hydroxylase | Relevant to prostate and vascular biology |
| CYP4F11 | Fatty acid omega hydroxylase | Potential role in lipid metabolism |
| CYP4F12 | Fatty acid omega hydroxylase | Expressed in liver and kidney |
| CYP4F22 | Omega hydroxylase involved in skin barrier lipids | Mutations cause ichthyosis |
| CYP4V2 | Fatty acid omega hydroxylase | Mutations linked to Bietti crystalline dystrophy |
| CYP4Z1 | Fatty acid hydroxylase | Studied in cancer |
| CYP4B1 | Fatty acid omega hydroxylase | Bioactivation of xenobiotics |
| CYP94A90 | Plant fatty acid omega-hydroxylase | Biosynthesis of floral nitro compounds in loquat |
| NADPH--hemoprotein reductase | Electron donor for P450 reactions | Essential cofactor for omega-1 hydroxylation |
| GPR75 | Receptor for 20-HETE | Mediates vascular effects of CYP4A products |
How Is fatty acid omega-1 hydroxylase activity Regulated?
Fatty acid omega-1 hydroxylase activity is regulated at multiple levels. Expression of CYP4A and CYP4F genes is induced by peroxisome proliferators, fasting, and dietary fatty acids, which increases enzyme abundance and activity. In experimental alcoholic liver disease, the type of dietary fatty acid influences omega and omega-1 hydroxylation rates, indicating nutritional regulation. Hormonal and metabolic signals, including those related to hypertension, can modulate CYP4A expression and 20-HETE production. Additionally, the availability of NADPH--hemoprotein reductase and NADPH affects catalytic flux through the P450 system.
fatty acid omega-1 hydroxylase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CYP4A11 | Hypertension, MASLD | Knockout mouse, overexpression in hepatocytes |
| CYP4A1 | Hypertension, renal function | Knockout rat, point mutation |
| CYP4F2 | Hypertension, 20-HETE synthesis | Knock-in humanized mouse |
| CYP4F22 | Ichthyosis | Point mutation knock-in in keratinocytes |
| CYP4V2 | Bietti crystalline dystrophy | Knockout iPSC-derived retinal cells |
Metabolic dysfunction-associated steatotic liver disease (MASLD)
CYP4 family fatty acid omega hydroxylase genes are differentially expressed in MASLD, and their expression correlates with disease progression. Omega-1 hydroxylation may contribute to lipid mediator production that influences hepatic steatosis and inflammation. RNA sequence database analyses have highlighted CYP4A and CYP4F subfamily members as potential biomarkers or therapeutic targets in MASLD.
Hypertension and vascular dysfunction
Arachidonic acid omega-hydroxylase activity, which includes omega-1 hydroxylation, produces 20-HETE, a vasoconstrictor that contributes to hypertension. Inhibition of renal arachidonic acid omega-hydroxylase with ABT reduces blood pressure in spontaneously hypertensive rats. Human and animal studies show that arachidonic acid intake promotes hypertension and target-organ fibrosis through CYP4A-mediated 20-HETE overproduction. The CYP/20-HETE/GPR75 axis is a recognized pathway in hypertension.
Alcoholic liver disease
Experimental alcoholic liver disease is associated with altered fatty acid omega and omega-1 hydroxylation, and these changes depend on the dietary fatty acid composition. This suggests that omega-1 hydroxylase activity may modify the severity of alcohol-induced liver injury.
Other diseases and plant biology
Mutations in CYP4F22 and CYP4V2, which have omega hydroxylase activity, cause ichthyosis and Bietti crystalline dystrophy, respectively. In plants, a promiscuous fatty acid omega-hydroxylase is involved in floral nitro compound biosynthesis, showing the broader biological impact of this enzyme class.
From fatty acid omega-1 hydroxylase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of CYP4A11 reduce 20-HETE and blood pressure? | CYP4A11 knockout mouse |
| Does a specific point mutation alter omega-1 hydroxylase activity? | Point-mutation knock-in in cell lines |
| Can human CYP4F2 rescue the phenotype in mice? | Knock-in humanized mouse |
| Where is CYP4A protein localized in tissues? | Tagged knock-in with fluorescent tag |
| Does overexpression of CYP4A increase fibrosis? | Overexpression in hepatic stellate cells |
| Is CYP4A required for alcoholic liver disease progression? | Knockout mouse fed alcohol diet |
How to Study the fatty acid omega-1 hydroxylase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS/MS | Hydroxylated fatty acid products | Enzyme activity in tissues |
| RNA-seq | CYP4 gene expression | Disease vs. normal comparison |
| qPCR | mRNA levels of CYP4A/F | Validation of expression changes |
| Western blot | Protein abundance of CYP4 enzymes | Model characterization |
| Immunohistochemistry | Tissue localization of CYP4 enzymes | Liver and kidney studies |
| 20-HETE ELISA | 20-HETE levels | Hypertension models |
| CRISPR knockout | Loss-of-function phenotype | Causal gene testing |
Enzyme activity assays
Fatty acid omega-1 hydroxylase activity can be measured using radiolabeled or fluorescent fatty acid substrates and HPLC or LC-MS detection of hydroxylated products. These assays are used to compare activity between wild-type and mutant enzymes, or in tissues from disease models.
Gene expression analysis
RNA-seq and qPCR are used to quantify CYP4A and CYP4F gene expression in tissues and cell models, as demonstrated in MASLD database analyses. Expression data help link omega-1 hydroxylase activity to disease progression.
Lipid mediator profiling
LC-MS/MS-based lipidomics can quantify 20-HETE and other eicosanoids derived from omega-1 hydroxylation, providing a readout of pathway activity in hypertension and liver disease models.
Genetic and pharmacological manipulation
Knockout mice, siRNA, and pharmacological inhibitors such as ABT are used to test the contribution of omega-1 hydroxylase activity to blood pressure and liver pathology. These approaches help establish causality.
How CRISPR Can Be Used to Study GO:0120502 fatty acid omega-1 hydroxylase activity
Knockout
CRISPR knockout of CYP4A or CYP4F genes in cell lines or animal models can eliminate fatty acid omega-1 hydroxylase activity, allowing researchers to test its role in 20-HETE production, blood pressure regulation, and liver disease progression. Knockout models are essential for distinguishing the contributions of individual CYP4 isoforms.
Point Mutation
Point mutations can be introduced into the catalytic domain of CYP4 enzymes to alter substrate binding or heme coordination, thereby modulating omega-1 hydroxylase activity without eliminating the protein. Such models help dissect the regioselectivity of omega-1 versus omega hydroxylation.
Knock-in
Knock-in of human CYP4A11 or CYP4F2 into mouse models can humanize the omega-1 hydroxylase pathway, enabling studies of human-specific enzyme kinetics and drug responses. Tagged knock-in with fluorescent or affinity tags facilitates protein localization and interaction studies.
Overexpression
Overexpression of CYP4A or CYP4F genes in cell lines or transgenic animals can increase omega-1 hydroxylase activity and 20-HETE production, modeling the overproduction seen in hypertension and fibrosis. Overexpression models are useful for testing inhibitors and downstream effects.
How EDITGENE Supports fatty acid omega-1 hydroxylase activity Research
Researchers studying fatty acid omega-1 hydroxylase activity-related genes often need to determine whether a candidate gene is causally involved in disease or whether a specific mutation alters enzyme function. EDITGENE provides CRISPR-based cell and animal models to address these questions with precision.
Contact EDITGENE today to design your custom CRISPR model for fatty acid omega-1 hydroxylase activity research.
Frequently Asked Questions About fatty acid omega-1 hydroxylase activity
What is fatty acid omega-1 hydroxylase activity?
It is a molecular function (GO:0120502) that catalyzes the hydroxylation of a fatty acid at the omega-1 carbon, using O2 and NADPH--hemoprotein reductase.
What genes are involved in fatty acid omega-1 hydroxylase activity?
The main genes are CYP4A and CYP4F subfamily members, including CYP4A11, CYP4A22, CYP4F2, CYP4F3, and CYP4F8.
What is the difference between omega and omega-1 hydroxylation?
Omega hydroxylation targets the terminal methyl carbon, while omega-1 hydroxylation targets the adjacent carbon; many CYP4 enzymes can perform both.
How is fatty acid omega-1 hydroxylase activity measured?
It is typically measured by LC-MS/MS or HPLC detection of hydroxylated fatty acid products using radiolabeled or fluorescent substrates.
What diseases are linked to fatty acid omega-1 hydroxylase activity?
It has been linked to hypertension, metabolic dysfunction-associated steatotic liver disease, and alcoholic liver disease.
What is the role of CYP4A in hypertension?
CYP4A enzymes produce 20-HETE, a vasoconstrictor that contributes to hypertension and target-organ fibrosis.
Can CRISPR knockout be used to study CYP4A genes?
Yes, CRISPR knockout of CYP4A genes eliminates omega-1 hydroxylase activity and helps test its role in disease models.
What is 20-HETE?
20-HETE is a bioactive eicosanoid produced from arachidonic acid by CYP4A-mediated omega hydroxylation, and it regulates vascular tone.
Is fatty acid omega-1 hydroxylase activity conserved in plants?
Yes, a promiscuous fatty acid omega-hydroxylase in loquat is involved in floral nitro compound biosynthesis.
How can I model fatty acid omega-1 hydroxylase activity in the lab?
You can use CRISPR knockout, point-mutation, knock-in, or overexpression cell models, as well as enzyme activity assays and lipidomics.
Conclusion
GO:0120502 fatty acid omega-1 hydroxylase activity is a cytochrome P450-dependent molecular function that generates hydroxylated fatty acids and bioactive lipids such as 20-HETE. Its dysregulation is implicated in hypertension, metabolic dysfunction-associated steatotic liver disease, and alcoholic liver disease, making it a compelling target for mechanistic and translational research. CRISPR-based models and biochemical assays provide robust tools to dissect the roles of CYP4A and CYP4F enzymes in health and disease.
References
- 1. Leahy C et al.. 2024. The fatty acid omega hydroxylase genes (CYP4 family) in the progression of metabolic dysfunction-associated steatotic liver disease (MASLD): An RNA sequence database analysis and review.. Biochem Pharmacol 228:116241 PMID: 38697309
- 2. Okita RT et al.. 2001. Cytochrome P450 4A fatty acid omega hydroxylases.. Curr Drug Metab 2(3):265-81 PMID: 11513330
- 3. Froogh G et al.. 2022. The CYP/20-HETE/GPR75 axis in hypertension.. Adv Pharmacol 94:1-25 PMID: 35659370
- 4. Yamaguchi T et al.. 2021. A promiscuous fatty acid ω-hydroxylase CYP94A90 is likely to be involved in biosynthesis of a floral nitro compound in loquat (Eriobotrya japonica).. New Phytol 231(3):1157-1170 PMID: 33932032
- 5. Fleming I. 2001. Cytochrome p450 and vascular homeostasis.. Circ Res 89(9):753-62 PMID: 11679404
- 6. Su P et al.. 1998. Inhibition of renal arachidonic acid omega-hydroxylase activity with ABT reduces blood pressure in the SHR.. Am J Physiol 275(2):R426-38 PMID: 9688677
- 7. Zhou Z et al.. 2026. Arachidonic acid intake promotes hypertension and target-organ fibrosis through CYP4A-mediated 20-HETE overproduction: Integrated evidence from human and animal studies.. Clin Exp Hypertens 48(1):2611130 PMID: 41491652
- 8. Amet Y et al.. 1998. Fatty acid omega- and (omega-1)-hydroxylation in experimental alcoholic liver disease: relationship to different dietary fatty acids.. Alcohol Clin Exp Res 22(7):1493-500 PMID: 9802534
