GO:0062076 acyl-CoA (8-3)-desaturase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0062076 acyl-CoA (8-3)-desaturase activity catalyzes the introduction of a double bond at the delta-5 position of acyl-CoA substrates, converting (8Z,11Z,14Z)-eicosatrienoyl-CoA to (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA (arachidonoyl-CoA).
• This activity is a cytochrome b5-dependent desaturase reaction that requires molecular oxygen and Fe(II) and produces Fe(III)-cytochrome b5 and water.
• The enzyme can also act on (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA to form (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-CoA, linking it to omega-3 fatty acid metabolism.
• Acyl-CoA (8-3)-desaturase activity is central to the biosynthesis of long-chain polyunsaturated fatty acids (PUFAs) such as arachidonic acid and eicosapentaenoic acid, which are precursors to eicosanoids.
• Altered expression of genes involved in lipid metabolism, including desaturases, has been observed in metabolic disorders such as ketosis in dairy cows.
• Studying this activity benefits from CRISPR-based models (knockout, point mutation, knock-in, overexpression) combined with lipidomics and transcriptomics to dissect gene function and metabolic flux [1,4].
Description
Acyl-CoA (8-3)-desaturase activity (GO:0062076) is a molecular function that introduces a double bond at the delta-5 position of specific acyl-CoA substrates, a critical step in the biosynthesis of long-chain polyunsaturated fatty acids (PUFAs). This activity converts (8Z,11Z,14Z)-eicosatrienoyl-CoA to (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA (arachidonoyl-CoA) and can also act on (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA to produce (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-CoA. The reaction is dependent on cytochrome b5 and molecular oxygen, and it is a key component of the fatty acid desaturation pathway that generates precursors for eicosanoids and other signaling lipids. Researchers study this activity to understand how cells regulate membrane lipid composition, energy homeostasis, and inflammatory signaling. Dysregulation of desaturase activities has been implicated in metabolic diseases, and expression of lipid metabolism genes, including desaturases, is altered in conditions such as ketosis in dairy cows. Moreover, the specificity of acyl-CoA reductases and related enzymes highlights the importance of acyl-CoA pools in lipid synthesis. Given its role in PUFA biosynthesis, acyl-CoA (8-3)-desaturase activity is a target for functional genomics and metabolic engineering. CRISPR-based approaches enable precise manipulation of genes encoding desaturases and associated proteins, facilitating the dissection of their contributions to lipid metabolism and disease [1,4].
acyl-CoA (8-3)-desaturase activity At A Glance
| GO ID | GO:0062076 |
|---|---|
| GO term | acyl-CoA (8-3)-desaturase activity |
| Ontology | molecular_function |
| Synonym | acyl-CoA D5-desaturase activity; acyl-CoA delta5-desaturase activity; acyl-CoA delta(5)-desaturase activity |
| Major function | Catalyzes the delta-5 desaturation of acyl-CoA substrates, converting eicosatrienoyl-CoA to eicosatetraenoyl-CoA (arachidonoyl-CoA) and eicosatetraenoyl-CoA to eicosapentaenoyl-CoA |
| Cofactors | Fe(II)-[cytochrome b5], molecular oxygen (O2), H+ |
| Products | Fe(III)-[cytochrome b5], H2O, desaturated acyl-CoA |
| Reaction direction | Forward desaturation (oxidative) |
| Pathway context | Long-chain polyunsaturated fatty acid biosynthesis |
What Is GO:0062076?
Acyl-CoA (8-3)-desaturase activity is defined as the catalysis of the reaction: (8Z,11Z,14Z)-eicosatrienoyl-CoA + 2 Fe(II)-[cytochrome b5] + 2 H+ + O2 = (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA + 2 Fe(III)-[cytochrome b5] + 2 H2O. The enzyme can also use a substrate with three double bonds, (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA, and add a fourth double bond to form (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-CoA. This activity is synonymous with acyl-CoA D5-desaturase, acyl-CoA delta5-desaturase, and acyl-CoA delta(5)-desaturase.
Why Is acyl-CoA (8-3)-desaturase activity Important in Cell Biology?
Acyl-CoA (8-3)-desaturase activity is essential for the endogenous synthesis of long-chain PUFAs, including arachidonic acid and eicosapentaenoic acid, which serve as precursors for eicosanoids and other lipid mediators. This activity influences membrane fluidity, inflammatory responses, and metabolic homeostasis. Alterations in desaturase expression or activity have been linked to metabolic disorders; for example, hepatic genes involved in lipid metabolism show altered expression in cows with ketosis. Understanding this activity provides insights into lipid-related diseases and offers targets for nutritional and pharmacological interventions.
• Produces arachidonic acid, a key precursor for prostaglandins, leukotrienes, and thromboxanes.
• Generates eicosapentaenoic acid (EPA), an omega-3 fatty acid with anti-inflammatory properties.
• Regulates membrane phospholipid composition and fluidity.
• Impacts energy metabolism and lipid storage.
• Its dysregulation is associated with metabolic disorders such as ketosis.
• Provides a model for studying cytochrome b5-dependent desaturation mechanisms.
• Relevant to the specificity of acyl-CoA pools and wax ester synthesis.
• Potential target for modifying fatty acid profiles in biotechnology and agriculture.
• Contributes to the understanding of PUFA-related signaling in health and disease.
• Enables functional validation of desaturase genes via CRISPR screens [1,4].
Molecular Mechanism of acyl-CoA (8-3)-desaturase activity
Substrate recognition and binding
In simple terms: The enzyme grabs a specific fatty acid chain attached to CoA.
The enzyme recognizes acyl-CoA substrates with a double bond at the 8-position and a chain length of 20 carbons, such as (8Z,11Z,14Z)-eicosatrienoyl-CoA. It can also bind (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA, indicating tolerance for an additional double bond at the omega-3 position.
Catalytic desaturation cycle
In simple terms: The enzyme removes two hydrogens and inserts a double bond using oxygen and iron.
The reaction requires molecular oxygen and two Fe(II) ions coordinated by cytochrome b5. The enzyme abstracts hydrogens from the substrate, forming a double bond at the delta-5 position, while oxygen is reduced to water and Fe(II) is oxidized to Fe(III)-cytochrome b5.
Electron transfer via cytochrome b5
In simple terms: Cytochrome b5 acts as an electron carrier to recharge the enzyme.
Cytochrome b5 donates electrons to the desaturase, enabling the reduction of the iron centers and completion of the catalytic cycle. The oxidation of Fe(II) to Fe(III) is a hallmark of the reaction.
Product release and downstream metabolism
In simple terms: The newly desaturated fatty acid is released for further use.
The products, (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA or (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-CoA, are released and can be incorporated into phospholipids or further metabolized to eicosanoids.
Regulation by substrate availability and gene expression
In simple terms: The enzyme's activity depends on how much substrate is available and how much enzyme is made.
Desaturase activity is influenced by the availability of acyl-CoA substrates and the expression levels of the desaturase gene. Nutritional and hormonal signals can modulate transcription, as seen in metabolic states like ketosis where lipid metabolism genes are differentially expressed.
Key Genes Involved in GO:0062076 acyl-CoA (8-3)-desaturase activity
The following genes and proteins are directly or indirectly involved in acyl-CoA (8-3)-desaturase activity and related lipid metabolic pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FADS1 | Encodes delta-5 desaturase, the enzyme responsible for GO:0062076 activity | Target for knockout/knock-in to study PUFA synthesis |
| FADS2 | Encodes delta-6 desaturase, upstream of delta-5 desaturation | Often studied together with FADS1 for pathway flux |
| CYB5A | Cytochrome b5, electron donor for desaturase | Knockout reduces desaturase activity |
| CYB5R3 | Cytochrome b5 reductase, regenerates cytochrome b5 | Affects electron supply for desaturation |
| ELOVL5 | Elongase that produces substrates for delta-5 desaturase | Modulates substrate availability |
| ELOVL2 | Elongase involved in PUFA synthesis | Contributes to substrate pool |
| SCD | Stearoyl-CoA desaturase, introduces first double bond | Upstream of PUFA pathway |
| ACSL | Acyl-CoA synthetase, activates fatty acids to acyl-CoA | Provides substrates for desaturation |
| PPARA | Transcription factor regulating lipid metabolism genes | Modulates desaturase expression |
| SREBF1 | Transcription factor controlling lipogenic genes | Regulates desaturase transcription |
| INSIG1 | Regulates SREBP processing | Indirectly affects desaturase levels |
| NR1H3 | Liver X receptor, regulates lipid metabolism | Controls desaturase expression |
| FABP | Fatty acid binding proteins | Intracellular transport of fatty acids |
| PLA2 | Phospholipase A2, releases PUFAs from membranes | Downstream of desaturation for eicosanoid production |
| COX | Cyclooxygenase, uses arachidonic acid | Links desaturation to prostaglandin synthesis |
| LOX | Lipoxygenase, uses arachidonic acid | Links desaturation to leukotriene synthesis |
| CYP450 | Cytochrome P450 epoxygenases | Metabolize PUFAs to epoxides |
How Is acyl-CoA (8-3)-desaturase activity Regulated?
Acyl-CoA (8-3)-desaturase activity is regulated at multiple levels. Transcription of desaturase genes is controlled by lipogenic transcription factors such as SREBP-1c and PPARalpha, which respond to nutritional and hormonal signals. Substrate availability, particularly the pool of acyl-CoA precursors, also influences flux through the desaturation step. Additionally, the redox state of cytochrome b5 and the availability of molecular oxygen affect catalytic efficiency. In metabolic disorders like ketosis, expression of hepatic lipid metabolism genes, including desaturases, is altered, indicating pathophysiological regulation.
acyl-CoA (8-3)-desaturase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FADS1 | Metabolic syndrome, inflammation | Knockout and overexpression in hepatocytes |
| FADS2 | PUFA-related disorders | Point mutation to alter substrate specificity |
| CYB5A | Lipid metabolism defects | Knock-in of tagged cytochrome b5 |
| ELOVL5 | Fatty acid elongation disorders | CRISPR knockout in cell lines |
| PPARA | Ketosis, fatty liver | Overexpression in bovine hepatocytes |
Metabolic disorders
Alterations in acyl-CoA (8-3)-desaturase activity can affect PUFA profiles, which are linked to metabolic syndrome, insulin resistance, and fatty liver disease. In dairy cows with ketosis, hepatic expression of genes involved in lipid metabolism is changed, suggesting a role in energy balance.
Inflammatory diseases
The products of delta-5 desaturation, arachidonic acid and EPA, are precursors to pro- and anti-inflammatory eicosanoids. Dysregulated desaturase activity may contribute to chronic inflammatory conditions.
Cardiovascular disease
PUFA composition of membranes influences cardiovascular health. Delta-5 desaturase activity determines the balance between omega-6 and omega-3 fatty acids, which impacts thrombosis and atherosclerosis risk.
From acyl-CoA (8-3)-desaturase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does FADS1 knockout reduce delta-5 desaturase activity? | FADS1 knockout cell line (e.g., HepG2) |
| How does a point mutation in the catalytic site affect substrate specificity? | CRISPR point mutation knock-in |
| Can tagged FADS1 be used to track subcellular localization? | Knock-in of fluorescent tag |
| Does overexpression of FADS1 increase PUFA production? | Overexpression stable cell line |
| What genes compensate for loss of delta-5 desaturase? | CRISPR library screening |
| How does ketosis alter desaturase expression? | Primary bovine hepatocytes with CRISPR modulation |
How to Study the acyl-CoA (8-3)-desaturase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS lipidomics | Acyl-CoA and PUFA levels | Quantify desaturase products |
| RNA-seq | Gene expression | Identify regulated desaturases |
| Western blot | Protein levels | Validate knockout/overexpression |
| Enzyme activity assay | Catalytic conversion | Measure delta-5 desaturase activity |
| CRISPR screen | Gene essentiality | Find modifiers of desaturase pathway |
| Fluorescence microscopy | Subcellular localization | Track tagged desaturase |
| qPCR | mRNA levels | Confirm gene expression changes |
Lipidomics and fatty acid profiling
Mass spectrometry-based lipidomics quantifies acyl-CoA species and PUFA products to measure desaturase activity directly.
Transcriptomics (RNA-seq)
RNA sequencing reveals expression changes in desaturase genes and related lipid metabolic pathways under different conditions.
Enzymatic assays
In vitro assays using recombinant enzyme and cytochrome b5 measure the conversion of substrates to products by monitoring NADH or oxygen consumption.
CRISPR screening
Genome-wide CRISPR knockout screens identify genes that modulate desaturase activity or PUFA sensitivity [1,4].
How CRISPR Can Be Used to Study GO:0062076 acyl-CoA (8-3)-desaturase activity
Knockout
CRISPR knockout of FADS1 or CYB5A eliminates delta-5 desaturase activity, allowing researchers to study the consequences for PUFA synthesis and cellular lipid composition.
Point Mutation
Introducing point mutations in the catalytic domain of FADS1 can dissect residues critical for substrate binding or iron coordination, providing mechanistic insights.
Knock-in
Knock-in of epitope tags or fluorescent proteins into the endogenous FADS1 locus enables real-time tracking of enzyme localization and interaction partners.
Overexpression
Overexpression of FADS1 or CYB5A via CRISPR activation or lentiviral delivery increases desaturase activity, useful for producing PUFAs in cell factories.
How EDITGENE Supports acyl-CoA (8-3)-desaturase activity Research
Researchers studying acyl-CoA (8-3)-desaturase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, disease, or drug response. EDITGENE provides a comprehensive suite of CRISPR services to enable precise, reproducible functional studies.
Contact EDITGENE today to design your custom CRISPR model for acyl-CoA (8-3)-desaturase activity research.
Frequently Asked Questions About acyl-CoA (8-3)-desaturase activity
What is acyl-CoA (8-3)-desaturase activity?
It is a molecular function (GO:0062076) that catalyzes the delta-5 desaturation of acyl-CoA substrates, converting eicosatrienoyl-CoA to arachidonoyl-CoA and eicosatetraenoyl-CoA to EPA.
What genes are involved in acyl-CoA (8-3)-desaturase activity?
The primary gene is FADS1, which encodes the delta-5 desaturase enzyme. Other supporting genes include CYB5A, CYB5R3, and ELOVL5.
What is the reaction catalyzed by acyl-CoA (8-3)-desaturase?
The enzyme converts (8Z,11Z,14Z)-eicosatrienoyl-CoA to (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA using oxygen and cytochrome b5, producing water and Fe(III)-cytochrome b5.
What are the synonyms for GO:0062076?
Synonyms include acyl-CoA D5-desaturase activity, acyl-CoA delta5-desaturase activity, and acyl-CoA delta(5)-desaturase activity.
Why is acyl-CoA (8-3)-desaturase activity important?
It produces arachidonic acid and EPA, which are precursors to eicosanoids and play roles in inflammation, membrane structure, and energy metabolism.
How is acyl-CoA (8-3)-desaturase activity regulated?
It is regulated by transcription factors like SREBP-1c and PPARalpha, substrate availability, and redox state of cytochrome b5.
What diseases are associated with acyl-CoA (8-3)-desaturase activity?
Altered activity is linked to metabolic disorders, inflammatory diseases, and cardiovascular disease [1,4].
How can I study acyl-CoA (8-3)-desaturase activity using CRISPR?
CRISPR knockout, point mutation, knock-in, and overexpression models allow precise manipulation of FADS1 and related genes to study their function.
What methods measure acyl-CoA (8-3)-desaturase activity?
Lipidomics, enzyme activity assays, RNA-seq, and CRISPR screens are commonly used [1,4].
Does acyl-CoA (8-3)-desaturase activity use omega-3 substrates?
Yes, it can act on (8Z,11Z,14Z,17Z)-eicosatetraenoyl-CoA to produce eicosapentaenoyl-CoA.
Conclusion
Acyl-CoA (8-3)-desaturase activity (GO:0062076) is a key enzymatic step in the biosynthesis of long-chain PUFAs, with critical roles in membrane biology, inflammation, and metabolism. Understanding its regulation and function through CRISPR-based models and multi-omics approaches can illuminate disease mechanisms and guide therapeutic development. EDITGENE offers comprehensive services to support such research.
References
- 1. Skrede S et al.. 1997. Thia fatty acids, metabolism and metabolic effects.. Biochim Biophys Acta 1344(2):115-31 PMID: 9030189
- 3. Wykle ML et al.. 1979. Acyl-CoA reductase specificity and synthesis of wax esters in mouse preputial gland tumors.. J Lipid Res 20(7):890-6 PMID: 39966
- 4. Zhu Y et al.. 2019. Expression patterns of hepatic genes involved in lipid metabolism in cows with subclinical or clinical ketosis.. J Dairy Sci 102(2):1725-1735 PMID: 30471902
