GO:0016213 acyl-CoA 6-desaturase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016213 acyl-CoA 6-desaturase activity catalyzes the introduction of a cis double bond at carbon 6 of acyl-CoA substrates, converting linoleoyl-CoA to gamma-linolenoyl-CoA and alpha-linolenoyl-CoA to stearidonoyl-CoA.
• The reaction requires molecular oxygen, reduced cytochrome b5, and Fe(II) cofactors, generating water and oxidized cytochrome b5.
• The enzyme is a front-end desaturase that introduces a double bond between a pre-existing double bond and the carboxyl end of the fatty acid.
• Key genes encoding this activity include FADS2 in mammals and desD in cyanobacteria, with orthologs across plants, fish, and protists [1,3,7].
• Altered acyl-CoA 6-desaturase activity is linked to cancer, metabolic disorders, and inflammatory conditions through changes in long-chain polyunsaturated fatty acid (PUFA) synthesis [1,2].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable precise dissection of GO:0016213 function in health and disease.
Description
Acyl-CoA 6-desaturase activity (GO:0016213) is a molecular function that introduces a cis double bond at carbon 6 of acyl-CoA substrates, a critical step in the biosynthesis of long-chain polyunsaturated fatty acids (PUFAs). This activity converts linoleoyl-CoA (18:2n-6) to gamma-linolenoyl-CoA (18:3n-6) and alpha-linolenoyl-CoA (18:3n-3) to stearidonoyl-CoA (18:4n-3), thereby initiating the pathway toward arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. The reaction is oxygen-dependent and uses reduced cytochrome b5 as an electron donor, with Fe(II) as a cofactor. Researchers study GO:0016213 because its products are precursors to bioactive lipid mediators that regulate inflammation, energy metabolism, and cell survival [1,2].
acyl-CoA 6-desaturase activity At A Glance
| GO ID | GO:0016213 |
|---|---|
| GO term | acyl-CoA 6-desaturase activity |
| Ontology | molecular_function |
| Synonym | delta6-desaturase activity; linoleoyl-CoA desaturase activity; fatty acid delta6-desaturase activity |
| Major function | Introduces a cis double bond at carbon 6 of acyl-CoA substrates, initiating long-chain PUFA synthesis |
| Cofactors | Molecular oxygen, reduced cytochrome b5, Fe(II) |
| Substrates | Linoleoyl-CoA (18:2n-6) and alpha-linolenoyl-CoA (18:3n-3) |
| Products | Gamma-linolenoyl-CoA (18:3n-6) and stearidonoyl-CoA (18:4n-3) |
| Cellular location | Endoplasmic reticulum membrane (in mammals) |
What Is GO:0016213?
According to the Gene Ontology, acyl-CoA 6-desaturase activity (GO:0016213) is defined as the catalysis of the introduction of a cis double bond at carbon 6 of acyl-CoAs, introducing a new double bond between a pre-existing double bond and the carboxyl-end of the fatty acid. Specific reactions include the conversion of (9Z,12Z)-octadecadienoyl-CoA to (6Z,9Z,12Z)-octadecatrienoyl-CoA and (9Z,12Z,15Z)-octadecatrienoyl-CoA to (6Z,9Z,12Z,15Z)-octadecatetraenoyl-CoA, using molecular oxygen, reduced cytochrome b5, and protons, and producing water and oxidized cytochrome b5. This activity is synonymous with delta6-desaturase, linoleoyl-CoA desaturase, and fatty acid delta6-desaturase, among other names.
Why Is acyl-CoA 6-desaturase activity Important in Cell Biology?
Acyl-CoA 6-desaturase activity is a rate-limiting step in the synthesis of long-chain PUFAs, which are essential for membrane fluidity, eicosanoid signaling, and energy homeostasis. Dysregulation of this activity has been implicated in cancer progression, where it supports redox balance and ferroptosis resistance, and in metabolic disorders linked to altered fatty acid profiles. Understanding GO:0016213 provides a foundation for developing therapeutic strategies targeting lipid metabolism.
• Initiates the biosynthesis of gamma-linolenic acid and stearidonic acid, precursors to anti-inflammatory and pro-resolving lipid mediators.
• Supports cancer cell survival by maintaining PUFA pools that balance lipid metabolic activity and redox-driven ferroptosis.
• Modulates membrane phospholipid composition, affecting cell signaling and receptor function.
• Contributes to energy metabolism regulation by long-chain fatty acids.
• Its activity is modulated by nutritional status and hormonal factors, as shown in cultured endothelial cells.
• Malonyl-CoA inhibits delta6 desaturation activity in rat liver microsomes, linking fatty acid synthesis to desaturation.
• Orthologs in marine fish are nutritionally regulated, impacting aquaculture and human nutrition.
• Plant and protist orthologs synthesize delta6 hexadecenoic acid and delta12 desaturase products, respectively [4,8].
• Computational models of FADS2 and acyl-CoA interaction reveal substrate binding determinants.
• CRISPR-based models enable causal testing of GO:0016213 in disease phenotypes.
Mechanism, Genes and Research Methods
Substrate Recognition and Binding
In simple terms: The enzyme grabs a fatty acid attached to CoA and positions it for modification.
Acyl-CoA 6-desaturase activity acts on acyl-CoA substrates, with linoleoyl-CoA and alpha-linolenoyl-CoA as primary substrates. Computational prediction of FADS2 and acyl-CoA interaction suggests specific residues mediate substrate binding and orientation. The enzyme introduces a double bond at carbon 6, between a pre-existing double bond and the carboxyl end, requiring the substrate to be in an acyl-CoA form.
Catalytic Cycle and Cofactors
In simple terms: The enzyme uses oxygen and a helper protein to create a new double bond, releasing water.
The desaturation reaction requires molecular oxygen, reduced cytochrome b5, and Fe(II) as cofactors. Two Fe(II) ions are oxidized to Fe(III) during the reaction, and cytochrome b5 is oxidized, producing water. The specific reactions convert (9Z,12Z)-octadecadienoyl-CoA to (6Z,9Z,12Z)-octadecatrienoyl-CoA and (9Z,12Z,15Z)-octadecatrienoyl-CoA to (6Z,9Z,12Z,15Z)-octadecatetraenoyl-CoA.
Regulation by Nutritional and Metabolic Signals
In simple terms: What you eat and how your body handles fats can change how active this enzyme is.
Delta6 desaturation activity in cultured human endothelial cells is modulated by fetal bovine serum, indicating hormonal or nutritional regulation. Malonyl-CoA inhibits delta6 desaturation activity in rat liver microsomes, linking fatty acid synthesis to desaturation. In marine fish, fatty acyl delta6 desaturase is nutritionally regulated, affecting highly unsaturated fatty acid synthesis.
Role in Long-Chain PUFA Synthesis
In simple terms: This enzyme is the first step in making specialized fats that control inflammation and cell signaling.
Acyl-CoA 6-desaturase activity initiates the pathway from linoleic and alpha-linolenic acids to gamma-linolenic and stearidonic acids, which are further elongated and desaturated to arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. These long-chain PUFAs regulate energy metabolism and are precursors to eicosanoids. In ovarian cancer cells, SCD1 and FADS2 balance lipid metabolic activity and redox-driven ferroptosis.
Evolutionary and Organismal Diversity
In simple terms: Different organisms use similar enzymes to make unique fatty acids.
A soluble delta6 palmitoyl-acyl carrier protein desaturase in Thunbergia alata endosperm synthesizes delta6 hexadecenoic acid. In Acanthamoeba castellanii, a microsomal delta12 desaturase activity is rapidly induced by chilling. Atlantic cod fatty acyl delta6 desaturase is cloned and functionally characterized, showing nutritional regulation.
Key Genes Involved in GO:0016213 acyl-CoA 6-desaturase activity
The following genes encode proteins with acyl-CoA 6-desaturase activity or directly regulate its function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FADS2 | Encodes delta6-desaturase, catalyzing the rate-limiting step in long-chain PUFA synthesis | Target for cancer, metabolic, and inflammatory disease studies |
| FADS1 | Encodes delta5-desaturase, acts downstream of FADS2 in PUFA synthesis | Often studied with FADS2 for pathway flux |
| SCD1 | Encodes stearoyl-CoA desaturase, balances lipid metabolism with FADS2 | Co-target in ferroptosis and cancer metabolism |
| ELOVL5 | Elongates PUFA products of FADS2 | Pathway context for GO:0016213 |
| ELOVL2 | Elongates PUFA products of FADS2 | Pathway context for GO:0016213 |
| CYB5A | Provides reduced cytochrome b5 for desaturation | Cofactor supply for GO:0016213 |
| CYB5R3 | Regenerates reduced cytochrome b5 | Redox partner for GO:0016213 |
| desD | Cyanobacterial delta6 desaturase | Model for enzyme mechanism |
| FAD2 | Plant delta12 desaturase, related to front-end desaturases | Comparative desaturase studies |
| FADS3 | Desaturase family member with unclear function | Potential regulatory role |
| ACSL1 | Activates fatty acids to acyl-CoA for desaturation | Substrate supply for GO:0016213 |
| ACSL4 | Activates PUFA to acyl-CoA, linked to ferroptosis | Redox-lipid crosstalk |
| PPARG | Regulates lipid metabolism genes including FADS2 | Transcriptional regulation |
| SREBF1 | Regulates lipogenic genes | Transcriptional regulation |
| NR1H3 | Liver X receptor, regulates lipid metabolism | Transcriptional regulation |
| FADS2 orthologs in fish | Nutritionally regulated delta6 desaturase | Aquaculture and nutrition |
| Thunbergia alata desaturase | Soluble delta6 palmitoyl-ACP desaturase | Plant lipid engineering |
How Is acyl-CoA 6-desaturase activity Regulated?
Acyl-CoA 6-desaturase activity is regulated at multiple levels. Nutritionally, fetal bovine serum modulates delta6 desaturation in cultured human endothelial cells. Metabolically, malonyl-CoA inhibits delta6 desaturation activity in rat liver microsomes. In marine fish, fatty acyl delta6 desaturase is nutritionally regulated, affecting PUFA synthesis. Transcriptional regulation by PPARG, SREBF1, and NR1H3 influences FADS2 expression. In cancer cells, SCD1 and FADS2 equipoise lipid metabolic activity and redox-driven ferroptosis.
acyl-CoA 6-desaturase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FADS2 | Ovarian cancer, ferroptosis resistance | FADS2 knockout in ovarian cancer cell lines |
| SCD1 | Cancer metabolism, ferroptosis | SCD1/FADS2 double knockout |
| FADS2 | Metabolic disorders, inflammation | Liver-specific FADS2 knockout mice |
| CYB5A | Redox imbalance | CYB5A point mutation knock-in |
| ACSL4 | Ferroptosis | ACSL4 overexpression |
Cancer Metabolism and Ferroptosis
In ascites-derived ovarian cancer cells, SCD1 and FADS2 balance lipid metabolic activity and redox-driven ferroptosis, suggesting that acyl-CoA 6-desaturase activity contributes to cancer cell survival under oxidative stress. Targeting this activity may sensitize cancer cells to ferroptosis.
Metabolic and Inflammatory Disorders
Altered long-chain PUFA synthesis, initiated by acyl-CoA 6-desaturase activity, is associated with metabolic disorders and inflammation. The products of GO:0016213 are precursors to eicosanoids that regulate immune responses.
Endothelial and Cardiovascular Biology
Delta6 desaturation activity in cultured human endothelial cells is modulated by fetal bovine serum, indicating a role in vascular lipid metabolism. Dysregulation may affect endothelial function and cardiovascular health.
From acyl-CoA 6-desaturase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does FADS2 loss alter PUFA synthesis? | FADS2 knockout cell line |
| Does a point mutation in the catalytic site abolish activity? | FADS2 point mutation knock-in |
| Can tagged FADS2 reveal subcellular localization? | Tagged knock-in of FADS2 |
| Does FADS2 overexpression protect from ferroptosis? | FADS2 overexpression in cancer cells |
| Does SCD1/FADS2 co-deletion affect tumor growth? | Double knockout in ovarian cancer cells |
| Does CYB5A mutation affect desaturation? | CYB5A point mutation knock-in |
How to Study the acyl-CoA 6-desaturase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lipidomics (LC-MS) | PUFA product levels | Pathway flux in cells |
| Enzyme activity assay | Delta6 desaturation rate | Kinetic studies [5,6] |
| Computational docking | FADS2-acyl-CoA interaction | Mutagenesis design |
| CRISPR knockout screen | Gene essentiality and ferroptosis | Cancer metabolism |
| RNA-seq | FADS2 and pathway gene expression | Transcriptional regulation |
| Western blot | FADS2 protein levels | Expression validation |
| Immunofluorescence | Subcellular localization | ER localization |
| Metabolite profiling | Acyl-CoA pools | Substrate availability |
Lipidomics and Fatty Acid Profiling
Mass spectrometry-based lipidomics measures the products of acyl-CoA 6-desaturase activity, such as gamma-linolenic acid and stearidonic acid, in cells and tissues. This method quantifies pathway flux and substrate-product ratios.
Enzyme Activity Assays
Radiolabeled or fluorescent acyl-CoA substrates are used to measure delta6 desaturation activity in microsomes or cell lysates [5,6]. These assays directly assess catalytic function and are useful for kinetic studies.
Computational Modeling and Docking
Molecular docking and dynamics simulations predict interactions between FADS2 and acyl-CoA substrates, identifying key residues for mutagenesis. This approach guides experimental validation.
CRISPR Screening and Functional Genomics
Genome-wide CRISPR knockout screens can identify genes that modulate sensitivity to ferroptosis in the context of FADS2 activity. Bioinformatics analysis of screen data reveals pathways linked to GO:0016213.
How CRISPR Can Be Used to Study GO:0016213 acyl-CoA 6-desaturase activity
Knockout
CRISPR knockout of FADS2 eliminates acyl-CoA 6-desaturase activity, reducing gamma-linolenic acid and stearidonic acid levels. This model is used to test the requirement for GO:0016213 in cancer cell proliferation and ferroptosis resistance.
Point Mutation
Point mutations in the catalytic domain of FADS2 can abolish or alter desaturase activity, allowing structure-function analysis. Computational predictions guide the selection of residues for mutation.
Knock-in
Knock-in of tagged FADS2 enables visualization of subcellular localization and interaction partners. Knock-in of disease-associated variants can model altered enzyme activity.
Overexpression
Overexpression of FADS2 increases acyl-CoA 6-desaturase activity and PUFA products, which can protect cells from ferroptosis. This model is useful for gain-of-function studies.
How EDITGENE Supports acyl-CoA 6-desaturase activity Research
Researchers studying acyl-CoA 6-desaturase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, cancer, or metabolic disease. EDITGENE provides CRISPR-based cell models and screening services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for acyl-CoA 6-desaturase activity research.
Frequently Asked Questions About acyl-CoA 6-desaturase activity
What is acyl-CoA 6-desaturase activity?
Acyl-CoA 6-desaturase activity (GO:0016213) is a molecular function that introduces a cis double bond at carbon 6 of acyl-CoA substrates, converting linoleoyl-CoA to gamma-linolenoyl-CoA and alpha-linolenoyl-CoA to stearidonoyl-CoA.
What genes are involved in acyl-CoA 6-desaturase activity?
The primary gene is FADS2, which encodes delta6-desaturase. Other related genes include FADS1, SCD1, CYB5A, and ACSL1 [1,2].
What is the reaction catalyzed by acyl-CoA 6-desaturase?
It converts (9Z,12Z)-octadecadienoyl-CoA to (6Z,9Z,12Z)-octadecatrienoyl-CoA and (9Z,12Z,15Z)-octadecatrienoyl-CoA to (6Z,9Z,12Z,15Z)-octadecatetraenoyl-CoA, using oxygen and reduced cytochrome b5.
What cofactors are required for acyl-CoA 6-desaturase activity?
Molecular oxygen, reduced cytochrome b5, and Fe(II) are required.
How is acyl-CoA 6-desaturase activity regulated?
It is regulated nutritionally, by malonyl-CoA inhibition, and transcriptionally by PPARG, SREBF1, and NR1H3 [1,5,6].
What diseases are associated with acyl-CoA 6-desaturase activity?
Altered activity is linked to cancer metabolism, ferroptosis resistance, metabolic disorders, and inflammation [1,2].
How can I study acyl-CoA 6-desaturase activity in the lab?
Use lipidomics, enzyme activity assays, CRISPR knockouts, and computational modeling [1,2,3].
What is the role of FADS2 in cancer?
FADS2, together with SCD1, balances lipid metabolic activity and redox-driven ferroptosis in ovarian cancer cells.
Can CRISPR be used to knockout FADS2?
Yes, CRISPR knockout of FADS2 eliminates acyl-CoA 6-desaturase activity and reduces PUFA products [1,2].
What are the products of acyl-CoA 6-desaturase activity?
The products are gamma-linolenoyl-CoA (18:3n-6) and stearidonoyl-CoA (18:4n-3).
Conclusion
Acyl-CoA 6-desaturase activity (GO:0016213) is a critical molecular function in long-chain PUFA synthesis, with far-reaching implications for cancer, metabolic, and inflammatory diseases [1,2]. Understanding its mechanism, regulation, and genetic control provides a foundation for therapeutic development. EDITGENE offers comprehensive CRISPR models and screening services to accelerate research on this important enzyme activity.
References
- 1. Nakamura MT et al.. 2014. Regulation of energy metabolism by long-chain fatty acids.. Prog Lipid Res 53:124-44 PMID: 24362249
- 2. Xuan Y et al.. 2022. SCD1/FADS2 fatty acid desaturases equipoise lipid metabolic activity and redox-driven ferroptosis in ascites-derived ovarian cancer cells.. Theranostics 12(7):3534-3552 PMID: 35547771
- 3. Cui J et al.. 2022. Molecular mechanism of interaction between fatty acid delta 6 desaturase and acyl-CoA by computational prediction.. AMB Express 12(1):69 PMID: 35680699
- 4. Cahoon EB et al.. 1994. delta 6 Hexadecenoic acid is synthesized by the activity of a soluble delta 6 palmitoyl-acyl carrier protein desaturase in Thunbergia alata endosperm.. J Biol Chem 269(44):27519-26 PMID: 7961667
- 5. Rosenthal MD et al.. 1983. Fatty acyl delta 6 desaturation activity of cultured human endothelial cells. Modulation by fetal bovine serum.. Biochim Biophys Acta 750(3):490-6 PMID: 6297606
- 6. de Gomez Dumm IN et al.. 1986. Effect of malonyl-CoA on delta 6 desaturation activity of rat liver microsomes.. Lipids 21(11):721-3 PMID: 3796237
- 7. Tocher DR et al.. 2006. Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.).. Lipids 41(11):1003-16 PMID: 17263300
- 8. Jones AL et al.. 1993. Rapid induction of microsomal delta 12(omega 6)-desaturase activity in chilled Acanthamoeba castellanii.. Biochem J 296 ( Pt 1)(Pt 1):183-8 PMID: 8250841
