GO:0004321 fatty-acyl-CoA synthase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004321 (fatty-acyl-CoA synthase activity) is a molecular_function term describing the catalysis of acetyl-CoA + n malonyl-CoA + 2n NADH + 2n NADPH + 4n H+ = a long-chain acyl-CoA + n CoA + n CO2 + 2n NAD+ + 2n NADP+.
• The reaction is carried out by large multifunctional fatty acid synthase (FAS) complexes that use acyl carrier protein (ACP) shuttling to assemble long-chain acyl-CoAs.
• FAS activity is a metabolic switch for de novo lipogenesis and can be regulated by autoacetylation in Drosophila.
• Altered fatty-acyl-CoA synthase activity contributes to hepatocellular carcinoma metabolic reprogramming and to atherosclerotic lipid accumulation.
• The term is distinct from fatty acyl-CoA synthetase (ligase) activity; GO:0004321 specifically covers the decarboxylating, oxoacyl- and enoyl-reducing synthase reaction.
• CRISPR knockout, point-mutation, knock-in and overexpression models enable causal testing of FAS genes in lipogenesis, cancer and metabolic disease.
Description
GO:0004321, fatty-acyl-CoA synthase activity, is a molecular_function term in the Gene Ontology that captures the catalytic activity of fatty acid synthase (FAS) systems. The reaction it describes is acetyl-CoA + n malonyl-CoA + 2n NADH + 2n NADPH + 4n H+ = a long-chain acyl-CoA + n CoA + n CO2 + 2n NAD+ + 2n NADP+. This activity is central to de novo lipogenesis, the pathway that converts acetyl-CoA and malonyl-CoA into long-chain acyl-CoAs for membrane biogenesis, energy storage and signaling. Researchers study GO:0004321 because it links carbon flux, redox balance and lipid homeostasis, and because its dysregulation is observed in cancer, atherosclerosis and heart failure. The term is often confused with fatty acyl-CoA synthetase (ligase) activity, which activates free fatty acids rather than synthesizing them from malonyl-CoA; GO:0004321 specifically denotes the synthase reaction that uses malonyl-CoA as the two-carbon donor and NADH/NADPH as reducing equivalents. In this article we integrate the QuickGO definition with verified PubMed literature to explain the mechanism, key genes, disease relevance and CRISPR-based research methods for GO:0004321.
fatty-acyl-CoA synthase activity At A Glance
| GO ID | GO:0004321 |
|---|---|
| GO term | fatty-acyl-CoA synthase activity |
| Ontology | molecular_function |
| Synonym | acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl- and enoyl-reducing); fatty acyl CoA synthase activity; yeast fatty acid synthase activity |
| Major function | Catalysis of the reaction: acetyl-CoA + n malonyl-CoA + 2n NADH + 2n NADPH + 4n H+ = a long-chain acyl-CoA + n CoA + n CO2 + 2n NAD+ + 2n NADP+ |
| Reaction direction | Biosynthetic (anabolic) formation of long-chain acyl-CoA |
| Substrates | Acetyl-CoA, malonyl-CoA, NADH, NADPH, H+ |
| Products | Long-chain acyl-CoA, CoA, CO2, NAD+, NADP+ |
| Representative enzymes | Fatty acid synthase (FAS) multifunctional complexes |
| Related activity | Distinct from fatty acyl-CoA synthetase (ligase) activity |
What Is GO:0004321?
In our own words, GO:0004321 describes the catalytic activity of an enzyme complex that builds a long-chain acyl-CoA from acetyl-CoA and malonyl-CoA. For every malonyl-CoA consumed, one carbon is lost as CO2, and reducing equivalents from NADH and NADPH are used to reduce the growing acyl chain. The overall stoichiometry is acetyl-CoA + n malonyl-CoA + 2n NADH + 2n NADPH + 4n H+ = a long-chain acyl-CoA + n CoA + n CO2 + 2n NAD+ + 2n NADP+. This activity is the defining catalytic function of fatty acid synthase (FAS) systems and is synonymous with acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl- and enoyl-reducing), fatty acyl CoA synthase activity and yeast fatty acid synthase activity.
Why Is fatty-acyl-CoA synthase activity Important in Cell Biology?
GO:0004321 is important because it defines the terminal catalytic step of de novo lipogenesis, a pathway that supplies long-chain acyl-CoAs for membrane lipids, energy storage and lipid signaling. In cancer, decreased propionyl-CoA metabolism and rewired acyl-CoA handling facilitate metabolic reprogramming and promote hepatocellular carcinoma. In cardiovascular disease, acyl-CoA synthase activity has been measured in atherosclerotic aortic tissue, and succinyl-CoA-based energy metabolism dysfunction is observed in chronic heart failure. In Drosophila, acetyl-CoA-mediated autoacetylation of FAS acts as a metabolic switch of de novo lipogenesis. Because the reaction consumes NADPH and NADH, it also connects to cellular redox homeostasis. Understanding GO:0004321 therefore has direct implications for oncology, cardiometabolic disease and metabolic engineering.
• Defines the core catalytic activity of fatty acid synthase (FAS) in de novo lipogenesis.
• Supplies long-chain acyl-CoAs for membrane biogenesis, energy storage and lipid signaling.
• Links carbon flux from acetyl-CoA/malonyl-CoA to NADH/NADPH redox balance.
• Dysregulated acyl-CoA metabolism facilitates metabolic reprogramming in hepatocellular carcinoma.
• Acyl-CoA synthase activity has been documented in atherosclerotic rabbit aortic tissue.
• Succinyl-CoA-based energy metabolism dysfunction is linked to chronic heart failure.
• FAS autoacetylation acts as a metabolic switch of de novo lipogenesis in Drosophila.
• Provides a target for metabolic engineering and anti-lipogenic therapeutic strategies.
• Distinguishing synthase from ligase activity is critical for correct annotation and drug design.
• Enables CRISPR-based causal testing of FAS genes in cancer and metabolic disease models.
Molecular Mechanism of fatty-acyl-CoA synthase activity
Substrate loading and acyl carrier protein shuttling
In simple terms: The enzyme first loads the starting materials onto a moving arm so they can be assembled step by step.
Fatty acid synthase systems use an acyl carrier protein (ACP) domain to shuttle the growing acyl chain between catalytic centers. Structural snapshots of human FAS have revealed how ACP shuttling coordinates substrate delivery during the reaction cycle. The initial acetyl-CoA and malonyl-CoA units are transferred to the ACP, and malonyl-CoA is decarboxylated to provide the two-carbon unit for chain extension. This step is essential for the overall reaction described by GO:0004321.
Decarboxylative condensation
In simple terms: Two carbon units are joined together while one carbon is released as carbon dioxide.
The synthase activity catalyzes a decarboxylative condensation in which the acetyl group is transferred to the malonyl-ACP, releasing CO2 and forming a beta-ketoacyl intermediate. This is the defining C-acyltransferase step of GO:0004321 and accounts for the CO2 product in the reaction equation. The reaction is driven by the exergonic decarboxylation of malonyl-CoA.
Reduction and dehydration cycles
In simple terms: The intermediate is chemically reduced and dehydrated repeatedly to build a saturated chain.
Following condensation, the beta-keto group is reduced by NADPH, dehydrated, and then reduced again by NADPH to form a saturated acyl chain. These reduction steps consume the NADH and NADPH shown in the GO:0004321 reaction. The cycle repeats n times, with each round adding two carbons to the growing acyl-CoA.
Chain termination and acyl-CoA release
In simple terms: Once the chain is long enough, it is released as a finished acyl-CoA molecule.
After the desired chain length is reached, the long-chain acyl-CoA is released from the FAS complex. The overall reaction produces a long-chain acyl-CoA, CoA, CO2, NAD+ and NADP+ as described in the GO:0004321 definition. In lactating bovine mammary fatty acid synthase, acetoacetyl-CoA reductase activity has been characterized as part of the FAS catalytic repertoire.
Cofactor and redox requirements
In simple terms: The reaction needs reducing power from NADH and NADPH to work.
GO:0004321 explicitly requires 2n NADH and 2n NADPH per n malonyl-CoA consumed, reflecting the reductive steps of the FAS cycle. This couples de novo lipogenesis to cellular redox state. In Drosophila, acetyl-CoA-mediated autoacetylation of FAS acts as a metabolic switch that regulates de novo lipogenesis, illustrating how cofactor availability and post-translational modification intersect with catalytic activity.
Regulation by autoacetylation and metabolic state
In simple terms: The enzyme can be switched on or off by chemical tags added in response to the cell's metabolic state.
FAS activity is not static; it can be regulated by autoacetylation. In Drosophila, acetyl-CoA-mediated autoacetylation of fatty acid synthase serves as a metabolic switch of de novo lipogenesis. This provides a mechanism by which the cell adjusts GO:0004321 activity according to acetyl-CoA availability. Such regulation helps coordinate lipogenesis with energy status.
Key Genes Involved in GO:0004321 fatty-acyl-CoA synthase activity
The genes and proteins below are directly or functionally associated with fatty-acyl-CoA synthase activity (GO:0004321) and its related acyl-CoA metabolism, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FASN | Multifunctional fatty acid synthase catalyzing GO:0004321 | Core enzyme for de novo lipogenesis; structural studies of ACP shuttling |
| ACP (acyl carrier protein domain) | Shuttles growing acyl chain between FAS catalytic centers | Essential for substrate channeling in FAS |
| ACACA | Acetyl-CoA carboxylase producing malonyl-CoA substrate | Supplies malonyl-CoA for GO:0004321 |
| ACACB | Acetyl-CoA carboxylase isoform regulating fatty acid oxidation | Metabolic context of acyl-CoA synthesis |
| ACSS2 | Acetyl-CoA synthetase generating acetyl-CoA | Provides acetyl-CoA for lipogenesis |
| ACSL | Fatty acyl-CoA synthetase (ligase) family | Distinct from GO:0004321; activates free fatty acids |
| ACAT | Acyl-CoA acyltransferase family | Related acyl-CoA handling in membranes |
| RpfB | Fatty acyl-CoA ligase in Xanthomonas campestris | Counteracts thioesterase activity of RpfF |
| RpfF | Diffusible signal factor synthase with thioesterase activity | Model for acyl-CoA ligase/synthase interplay |
| SCS | Succinyl-CoA synthetase | Succinyl-CoA energy metabolism in heart failure |
| Propionyl-CoA metabolism genes | Propionyl-CoA handling | Decreased propionyl-CoA metabolism in hepatocellular carcinoma |
| FAS (yeast) | Yeast fatty acid synthase complex | Synonym reference for GO:0004321 |
| Mammary FAS | Lactating bovine mammary fatty acid synthase | Acetoacetyl-CoA reductase activity of FAS |
| Aortic acyl-CoA synthase | Acyl-CoA synthase activity in arterial tissue | Atherosclerosis model |
| Drosophila FAS | Fatty acid synthase in Drosophila | Autoacetylation switch of de novo lipogenesis |
How Is fatty-acyl-CoA synthase activity Regulated?
GO:0004321 activity is regulated at multiple levels. In Drosophila, acetyl-CoA-mediated autoacetylation of fatty acid synthase acts as a metabolic switch of de novo lipogenesis, linking enzyme activity to acetyl-CoA availability. The reaction also depends on the supply of malonyl-CoA and reducing equivalents (NADH/NADPH), so upstream metabolic pathways influence flux through GO:0004321. In disease contexts, decreased propionyl-CoA metabolism facilitates metabolic reprogramming in hepatocellular carcinoma, indicating that acyl-CoA pool composition can indirectly shape lipogenic activity. Additionally, acyl-CoA synthase activity has been measured in atherosclerotic aortic tissue, suggesting that local lipid loading states may influence enzyme activity. These observations support a model in which GO:0004321 is controlled by substrate availability, redox balance and post-translational modification.
fatty-acyl-CoA synthase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FASN | Hepatocellular carcinoma metabolic reprogramming | FASN knockout hepatoma cell line |
| Propionyl-CoA metabolism genes | Hepatocellular carcinoma | Point-mutation knock-in in liver cancer cells |
| SCS | Chronic heart failure | Cardiomyocyte knockout model |
| ACSL | Atherosclerosis | Aortic smooth muscle cell overexpression |
| RpfB/RpfF | Bacterial signaling | Bacterial knockout and complementation |
Hepatocellular carcinoma and metabolic reprogramming
Decreased propionyl-CoA metabolism facilitates metabolic reprogramming and promotes hepatocellular carcinoma. Because GO:0004321 supplies long-chain acyl-CoAs for lipogenesis, altered acyl-CoA metabolism can support the lipid demands of proliferating tumor cells. This makes fatty-acyl-CoA synthase activity a relevant node in cancer metabolism research.
Atherosclerosis and arterial lipid accumulation
Fatty acyl CoA synthetase activity has been measured in normal and atherosclerotic rabbit aortic tissue. Although this measures ligase activity rather than GO:0004321 directly, it highlights the importance of acyl-CoA metabolism in arterial lipid accumulation. Distinguishing synthase from ligase activity is essential when interpreting such studies.
Chronic heart failure and energy metabolism
Succinyl-CoA-based energy metabolism dysfunction has been reported in chronic heart failure. This connects acyl-CoA metabolism to cardiac energy failure. Because GO:0004321 consumes NADH and NADPH, its activity is also tied to the redox balance that is perturbed in failing hearts.
Bacterial signaling and acyl-CoA ligase interplay
In Xanthomonas campestris, RpfB is a fatty acyl-CoA ligase required to counteract the thioesterase activity of the RpfF diffusible signal factor synthase. This illustrates how acyl-CoA ligase/synthase activities can modulate signaling molecules, providing a comparative model for understanding acyl-CoA enzyme families.
From fatty-acyl-CoA synthase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does FASN loss reduce de novo lipogenesis? | FASN knockout cell line |
| Does a specific catalytic residue control GO:0004321 activity? | Point-mutation knock-in of FASN catalytic domain |
| Can a tagged FASN track ACP shuttling? | Tagged knock-in of FASN with fluorescent tag |
| Does FASN overexpression increase lipid storage? | FASN overexpression stable cell line |
| Does autoacetylation regulate FAS activity? | Point-mutation of acetylation sites in Drosophila FAS |
| Does acyl-CoA ligase counteract thioesterase signaling? | RpfB knockout in Xanthomonas campestris |
How to Study the fatty-acyl-CoA synthase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH oxidation assay | Fatty-acyl-CoA synthase catalytic activity | Enzyme kinetics of FAS |
| Cryo-EM | Structural snapshots of ACP shuttling | Mechanistic studies of human FAS |
| 13C metabolic flux analysis | Flux through de novo lipogenesis | Cancer metabolism |
| Lipidomics | Long-chain acyl-CoA product levels | Lipid storage and signaling |
| CRISPR knockout | Loss-of-function phenotype | Causal gene testing |
| CRISPR point mutation | Specific residue function | Catalytic mechanism |
| Western blot | FAS protein expression | Overexpression validation |
| Immunofluorescence | Subcellular localization | FAS complex assembly |
Enzymatic activity assays
Fatty-acyl-CoA synthase activity can be measured spectrophotometrically by monitoring NADPH oxidation at 340 nm in the presence of acetyl-CoA and malonyl-CoA. This directly quantifies GO:0004321 catalytic activity. Such assays have been used to characterize FAS from lactating bovine mammary tissue and acyl-CoA synthase activity in aortic tissue.
Structural biology and ACP shuttling
Cryo-EM and X-ray crystallography have provided snapshots of acyl carrier protein shuttling in human fatty acid synthase. These structural methods reveal how the ACP domain delivers substrates to catalytic centers, informing mechanism-based inhibitor design for GO:0004321.
Metabolic flux and lipidomics
Stable isotope tracing with 13C-acetyl-CoA or 13C-malonyl-CoA combined with mass spectrometry can quantify flux through de novo lipogenesis. Lipidomics measures the long-chain acyl-CoA products of GO:0004321. These approaches are used in cancer metabolism studies such as hepatocellular carcinoma.
Genetic and CRISPR screens
CRISPR knockout and point-mutation models allow causal testing of FAS genes. In Drosophila, genetic manipulation of FAS autoacetylation sites has been used to study de novo lipogenesis. In bacteria, RpfB knockout and complementation have been used to study acyl-CoA ligase function.
How CRISPR Can Be Used to Study GO:0004321 fatty-acyl-CoA synthase activity
Knockout
CRISPR knockout of FASN or related acyl-CoA genes eliminates GO:0004321 activity, allowing researchers to test its requirement for de novo lipogenesis, cell proliferation and lipid storage. Knockout models are particularly useful in cancer cell lines where metabolic reprogramming is observed.
Point Mutation
Point-mutation knock-in can alter specific catalytic residues in the FAS ketosynthase, reductase or ACP domains. This enables precise dissection of the decarboxylative condensation and reduction steps that define GO:0004321. Such models complement structural studies of ACP shuttling.
Knock-in
Tagged knock-in of FASN with fluorescent or affinity tags allows real-time tracking of the enzyme complex and its ACP shuttling dynamics. This is valuable for imaging studies and for validating interaction partners in the GO:0004321 reaction cycle.
Overexpression
Overexpression of FASN or acyl-CoA synthase genes increases flux through GO:0004321, modeling the lipogenic phenotype seen in cancer and metabolic disease. Overexpression models are used to test whether increased synthase activity is sufficient to drive lipid accumulation.
How EDITGENE Supports fatty-acyl-CoA synthase activity Research
Researchers studying fatty-acyl-CoA synthase activity-related genes often need to determine whether a candidate gene is causally involved in lipogenesis, cancer metabolism or cardiovascular disease. EDITGENE provides CRISPR-based cell model services that enable precise knockout, point-mutation, knock-in and overexpression of genes such as FASN and related acyl-CoA enzymes, supported by library screening and bioinformatics.
Contact EDITGENE today to design your custom CRISPR model for fatty-acyl-CoA synthase activity research.
Frequently Asked Questions About fatty-acyl-CoA synthase activity
What is fatty-acyl-CoA synthase activity?
Fatty-acyl-CoA synthase activity (GO:0004321) is a molecular_function term describing the catalysis of acetyl-CoA + n malonyl-CoA + 2n NADH + 2n NADPH + 4n H+ = a long-chain acyl-CoA + n CoA + n CO2 + 2n NAD+ + 2n NADP+.
What genes are involved in fatty-acyl-CoA synthase activity?
Key genes include FASN, which encodes the multifunctional fatty acid synthase, and related acyl-CoA metabolism genes such as ACACA, ACACB and ACSS2.
What is the difference between fatty-acyl-CoA synthase and fatty acyl-CoA synthetase?
Fatty-acyl-CoA synthase (GO:0004321) builds long-chain acyl-CoA from acetyl-CoA and malonyl-CoA, while fatty acyl-CoA synthetase (ligase) activates free fatty acids; the two activities are distinct.
How is fatty-acyl-CoA synthase activity regulated?
It is regulated by substrate availability, redox state and post-translational modification such as autoacetylation of FAS in Drosophila.
What diseases are linked to fatty-acyl-CoA synthase activity?
Altered acyl-CoA metabolism is linked to hepatocellular carcinoma, atherosclerosis and chronic heart failure.
How can I measure fatty-acyl-CoA synthase activity?
It can be measured by NADPH oxidation assays, metabolic flux analysis and lipidomics, as used in FAS characterization studies.
What is the role of acyl carrier protein in fatty-acyl-CoA synthase activity?
The acyl carrier protein domain shuttles the growing acyl chain between catalytic centers, as revealed by structural snapshots of human FAS.
Can CRISPR be used to study fatty-acyl-CoA synthase activity?
Yes, CRISPR knockout, point-mutation, knock-in and overexpression models allow causal testing of FAS genes and their role in lipogenesis.
What is the GO ID for fatty-acyl-CoA synthase activity?
The GO ID is GO:0004321.
What are synonyms for fatty-acyl-CoA synthase activity?
Synonyms include acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl- and enoyl-reducing), fatty acyl CoA synthase activity and yeast fatty acid synthase activity.
Conclusion
GO:0004321 fatty-acyl-CoA synthase activity defines the central catalytic reaction of de novo lipogenesis, converting acetyl-CoA and malonyl-CoA into long-chain acyl-CoAs using NADH and NADPH. Its mechanism involves ACP shuttling, decarboxylative condensation and reduction cycles, as revealed by structural and biochemical studies. Dysregulation of this activity is linked to hepatocellular carcinoma, atherosclerosis and heart failure, and it is regulated by autoacetylation in Drosophila. CRISPR-based knockout, point-mutation, knock-in and overexpression models provide powerful tools to dissect the causal roles of FAS genes. EDITGENE offers these services to accelerate research on fatty-acyl-CoA synthase activity and related metabolic pathways.
References
- 1. Sun J et al.. 2023. Decreased propionyl-CoA metabolism facilitates metabolic reprogramming and promotes hepatocellular carcinoma.. J Hepatol 78(3):627-642 PMID: 36462680
- 2. Smith PB et al.. 1982. Acyl-CoA synthase and acyltransferase activity in developing skeletal muscle membranes.. Biochim Biophys Acta 713(1):128-35 PMID: 7138893
- 3. Schultz K et al.. 2025. Snapshots of acyl carrier protein shuttling in human fatty acid synthase.. Nature 641(8062):520-528 PMID: 39979457
- 4. Takada S et al.. 2022. Succinyl-CoA-based energy metabolism dysfunction in chronic heart failure.. Proc Natl Acad Sci U S A 119(41):e2203628119 PMID: 36201541
- 5. Dodds PF et al.. 1981. Acetoacetyl-CoA reductase activity of lactating bovine mammary fatty acid synthase.. J Biol Chem 256(12):6282-90 PMID: 7016867
- 6. Brecher P et al.. 1975. Fatty acyl CoA synthetase activity in normal and atherosclerotic rabbit aortic tissue.. Atherosclerosis 22(3):485-9 PMID: 1201148
- 7. Bi H et al.. 2014. Xanthomonas campestris RpfB is a fatty Acyl-CoA ligase required to counteract the thioesterase activity of the RpfF diffusible signal factor (DSF) synthase.. Mol Microbiol 93(2):262-75 PMID: 24866092
- 8. Miao T et al.. 2022. Acetyl-CoA-mediated autoacetylation of fatty acid synthase as a metabolic switch of de novo lipogenesis in Drosophila.. Proc Natl Acad Sci U S A 119(49):e2212220119 PMID: 36459649
