GO:0003989 acetyl-CoA carboxylase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003989 acetyl-CoA carboxylase activity catalyzes the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA, the committed step in fatty acid biosynthesis.
• The reaction consumes ATP, acetyl-CoA, and bicarbonate, and releases ADP, phosphate, and malonyl-CoA.
• Two major architectural classes exist: multi-subunit (bacterial/plant plastid) and multi-domain (animal/yeast) acetyl-CoA carboxylases.
• ACACA (ACC1) and ACACB (ACC2) are the principal human genes encoding cytosolic and mitochondrial acetyl-CoA carboxylase isoforms, respectively.
• Acetyl-CoA carboxylase activity is regulated by phosphorylation, allosteric effectors, and hormonal signals, and is a target for metabolic, anti-platelet, and anti-infective research.
• Dysregulated acetyl-CoA carboxylase activity is linked to ferroptosis, cancer metabolism, and metabolic disorders, making it a key experimental target.
Description
Acetyl-CoA carboxylase activity (GO:0003989) is a molecular function that catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, using ATP and bicarbonate. This reaction is the first committed and rate-limiting step in fatty acid biosynthesis, and it is therefore a central node in lipid metabolism across bacteria, plants, and animals. The enzyme is conserved in all kingdoms of life, but its structural organization varies: bacteria and plant plastids often use multi-subunit complexes, whereas animals and fungi typically use large multi-domain polypeptides. In humans, two main isoforms exist: ACACA (ACC1), which is cytosolic and supports lipogenesis, and ACACB (ACC2), which is associated with the mitochondrial outer membrane and regulates fatty acid oxidation through malonyl-CoA signaling. Because of its pivotal role in lipid homeostasis, acetyl-CoA carboxylase activity is a major focus in metabolic disease, cancer, and ferroptosis research. Researchers study this activity using biochemical assays, genetic knockout and knock-in models, and pharmacological inhibitors, and recent work continues to uncover new regulatory and structural features.
acetyl-CoA carboxylase activity At A Glance
| GO ID | GO:0003989 |
|---|---|
| GO term | acetyl-CoA carboxylase activity |
| Ontology | molecular_function |
| Synonym | acetyl-CoA:carbon-dioxide ligase (ADP-forming); acetyl coenzyme A carboxylase activity |
| Definition | Catalysis of the reaction: ATP + acetyl-CoA + HCO3- = ADP + phosphate + malonyl-CoA. |
| Major function | First committed step of fatty acid biosynthesis; produces malonyl-CoA for lipogenesis and regulates fatty acid oxidation. |
| Cofactor | Biotin (covalently attached to the biotin carboxyl carrier protein domain). |
| Substrates | ATP, acetyl-CoA, bicarbonate (HCO3-). |
| Products | ADP, phosphate, malonyl-CoA. |
| Representative genes | ACACA (ACC1), ACACB (ACC2) in humans; accBC/accDA in bacteria; ACC1/ACC2 in yeast. |
What Is GO:0003989?
According to the Gene Ontology, acetyl-CoA carboxylase activity (GO:0003989) is defined as the catalysis of the reaction: ATP + acetyl-CoA + HCO3- = ADP + phosphate + malonyl-CoA. In other words, this function transfers a carboxyl group from bicarbonate to acetyl-CoA, consuming ATP, to produce malonyl-CoA, which is the direct donor of two-carbon units for fatty acid elongation. The reaction requires biotin as a covalently bound cofactor and proceeds through two half-reactions: biotin carboxylation and carboxyl transfer.
Why Is acetyl-CoA carboxylase activity Important in Cell Biology?
Acetyl-CoA carboxylase activity is essential for fatty acid synthesis and for the regulation of fatty acid oxidation, because malonyl-CoA both serves as a building block for lipogenesis and inhibits carnitine palmitoyltransferase 1 (CPT1), controlling the entry of fatty acids into mitochondria. This dual role places the enzyme at the center of cellular energy management, membrane biogenesis, and lipid signaling. Consequently, changes in acetyl-CoA carboxylase activity contribute to metabolic disorders, cancer progression, and ferroptosis, and the enzyme is a validated target for antibiotics, herbicides, and anti-platelet agents.
• Provides malonyl-CoA for de novo fatty acid synthesis, a requirement for membrane lipid production and energy storage.
• Regulates fatty acid oxidation by controlling malonyl-CoA levels, which inhibit CPT1 and mitochondrial fatty acid uptake.
• Is a target for anti-obesity and anti-diabetic drug discovery because of its central role in lipid homeostasis.
• Bacterial acetyl-CoA carboxylase is essential for viability and is exploited for antibiotic development.
• Plant acetyl-CoA carboxylase is the target of commercial herbicides, making it important in agriculture.
• Acetyl-CoA carboxylase activation can disrupt iron homeostasis and drive ferroptosis, linking lipid metabolism to cell death pathways.
• In platelets, acetyl-CoA carboxylase inhibition increases tubulin acetylation and impairs aggregation, suggesting a role in thrombosis.
• The enzyme is subject to hormonal regulation, including insulin and glucagon, which control its phosphorylation state and activity.
• Structural studies of diverse acetyl-CoA carboxylases inform selective inhibitor design and evolutionary biology.
• Genetic models (knockout, knock-in) are widely used to dissect isoform-specific functions in vivo.
Molecular Mechanism and Cellular Context of acetyl-CoA carboxylase activity
Overall catalytic reaction
In simple terms: The enzyme uses energy from ATP to attach a carboxyl group to acetyl-CoA, making malonyl-CoA.
Acetyl-CoA carboxylase catalyzes the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA, with bicarbonate as the carbon source. The reaction consumes one ATP per acetyl-CoA and releases ADP, inorganic phosphate, and malonyl-CoA. This is the committed step in fatty acid biosynthesis and is highly conserved across species.
Two-step catalytic cycle
In simple terms: The enzyme first activates bicarbonate and then transfers it to acetyl-CoA, using a swinging biotin arm.
The catalytic cycle occurs in two half-reactions: first, biotin carboxylase (BC) activates bicarbonate by ATP-dependent carboxylation of the biotin prosthetic group, forming carboxybiotin; second, carboxyltransferase (CT) transfers the carboxyl group from carboxybiotin to acetyl-CoA, yielding malonyl-CoA. The biotin is covalently attached to the biotin carboxyl carrier protein (BCCP) domain, which shuttles between the BC and CT active sites. In some bacteria, these activities reside on separate subunits, while in animals they are fused into a single polypeptide.
Structural organization: multi-subunit vs multi-domain
In simple terms: Some organisms build the enzyme from separate pieces, while others use one large protein with multiple modules.
Bacterial and plant plastid acetyl-CoA carboxylases are typically multi-subunit complexes composed of biotin carboxylase, biotin carboxyl carrier protein, and carboxyltransferase subunits. In contrast, animal and yeast enzymes are multi-domain proteins in which these activities are combined on a single polypeptide chain. A recent study showed that Chloroflexus aurantiacus acetyl-CoA carboxylase has evolved a fused biotin carboxylase and biotin carboxyl carrier protein to complete carboxylation, illustrating evolutionary diversity. Wheat acetyl-CoA carboxylase is a multi-subunit enzyme in plastids, important for herbicide sensitivity.
Cofactors and metal requirements
In simple terms: The enzyme needs biotin and magnesium to work.
Biotin is covalently linked to a conserved lysine residue in the BCCP domain and is essential for carboxyl transfer. The biotin carboxylase half-reaction requires Mg2+ to coordinate ATP and bicarbonate. No other metal cofactors are strictly required for the overall reaction, although some bacterial enzymes may have additional regulatory metal sites.
Regulation by phosphorylation and allosteric effectors
In simple terms: The enzyme can be turned on or off by chemical signals, such as hormones and metabolites.
Acetyl-CoA carboxylase activity is regulated by phosphorylation and dephosphorylation in response to hormones such as insulin and glucagon. Allosteric activators include citrate, which promotes polymerization and activation, while long-chain acyl-CoAs inhibit the enzyme. In platelets, inhibition of acetyl-CoA carboxylase with CP640.186 increases tubulin acetylation and impairs thrombin-induced aggregation, demonstrating pharmacological regulation. Bacterial acetyl-CoA carboxylase is also subject to feedback regulation and is a target for selective inhibitors.
Key Genes Involved in GO:0003989 acetyl-CoA carboxylase activity
The following genes and proteins are directly involved in acetyl-CoA carboxylase activity or its regulation across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACACA (ACC1) | Cytosolic acetyl-CoA carboxylase; produces malonyl-CoA for fatty acid synthesis | Target for obesity, cancer, and lipogenesis studies |
| ACACB (ACC2) | Mitochondrial-associated acetyl-CoA carboxylase; regulates fatty acid oxidation via malonyl-CoA | Target for metabolic disease and fatty acid oxidation research |
| BC (biotin carboxylase) | Catalyzes ATP-dependent carboxylation of biotin | Bacterial and plant enzyme subunit; antibiotic/herbicide target |
| BCCP (biotin carboxyl carrier protein) | Carries covalently bound biotin; shuttles carboxyl groups | Essential for catalysis; structural studies |
| CT (carboxyltransferase) | Transfers carboxyl from carboxybiotin to acetyl-CoA | Target for selective inhibitors |
| accBC (bacterial) | Multi-subunit acetyl-CoA carboxylase genes | Model for antibiotic discovery |
| accDA (bacterial) | Carboxyltransferase subunits in bacteria | Essential bacterial genes; validation of inhibitors |
| ACC1 (yeast) | Multi-domain acetyl-CoA carboxylase | Model for regulation and structure-function studies |
| ACC2 (yeast) | Mitochondrial acetyl-CoA carboxylase isoform | Role in fatty acid oxidation |
| Chloroflexus aurantiacus ACC | Fused BC-BCCP enzyme | Evolutionary and structural studies |
| Wheat ACC | Plastid multi-subunit enzyme | Herbicide target and plant lipid metabolism |
| CPT1 (carnitine palmitoyltransferase 1) | Inhibited by malonyl-CoA; regulates fatty acid oxidation | Downstream effector of acetyl-CoA carboxylase activity |
| AMPK | Phosphorylates and inhibits acetyl-CoA carboxylase | Energy sensor regulating lipid metabolism |
| ACC in platelets | Supports tubulin acetylation and aggregation | Anti-platelet drug target |
| ACC in ferroptosis | Activation disrupts iron homeostasis | Link to ferroptosis and oxidative stress |
How Is acetyl-CoA carboxylase activity Regulated?
Acetyl-CoA carboxylase activity is regulated at multiple levels. Hormonal signals such as insulin promote dephosphorylation and activation, whereas glucagon and epinephrine stimulate phosphorylation and inhibition. AMP-activated protein kinase (AMPK) phosphorylates acetyl-CoA carboxylase, reducing its activity and favoring fatty acid oxidation. Allosteric regulation by citrate (activator) and long-chain acyl-CoAs (inhibitors) fine-tunes enzyme activity in response to metabolic state. In bacteria, acetyl-CoA carboxylase is regulated by feedback inhibition and is essential for membrane lipid synthesis. Pharmacological inhibitors such as CP640.186 can modulate activity in platelets, affecting tubulin acetylation and aggregation.
acetyl-CoA carboxylase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACACA | Cancer (lipogenesis), obesity | Knockout or knockdown in cancer cell lines; overexpression in adipocytes |
| ACACB | Type 2 diabetes, fatty acid oxidation disorders | Liver-specific knockout mice; point mutation of phosphorylation sites |
| ACACA/ACACB | Ferroptosis | CRISPR activation or knockout in ferroptosis-sensitive cells |
| ACC (platelet) | Thrombosis | Platelet-specific knockout or pharmacological inhibition |
| Bacterial ACC | Bacterial infections | Essential gene knockout in model bacteria; inhibitor screening |
Cancer metabolism and lipogenesis
Many cancer cells rely on de novo fatty acid synthesis for membrane production and energy, and acetyl-CoA carboxylase activity is often upregulated to support this demand. Targeting acetyl-CoA carboxylase with inhibitors or genetic knockdown reduces tumor cell proliferation in preclinical models, making it a candidate for cancer therapy. The enzyme's role in providing malonyl-CoA for lipogenesis links it to oncogenic signaling pathways.
Ferroptosis and iron homeostasis
Recent evidence shows that activation of acetyl-CoA carboxylase disrupts iron homeostasis and drives ferroptosis, a form of regulated cell death characterized by lipid peroxidation. This connects acetyl-CoA carboxylase activity to oxidative stress and iron metabolism, with implications for cancer and neurodegenerative diseases. Modulating the enzyme may therefore influence ferroptosis sensitivity in disease contexts.
Metabolic disorders and thrombosis
Dysregulated acetyl-CoA carboxylase activity contributes to obesity, insulin resistance, and dyslipidemia by altering fatty acid synthesis and oxidation. In platelets, inhibition of acetyl-CoA carboxylase increases tubulin acetylation and impairs thrombin-induced aggregation, suggesting a potential role in thrombosis and cardiovascular disease. These findings highlight the enzyme as a therapeutic target for metabolic and thrombotic disorders.
From acetyl-CoA carboxylase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ACACA loss reduce lipogenesis and tumor growth? | ACACA knockout cancer cell lines and xenografts |
| How does ACACB phosphorylation regulate fatty acid oxidation? | Point-mutation knock-in of phospho-null or phospho-mimetic residues |
| Can acetyl-CoA carboxylase activation induce ferroptosis? | Overexpression or CRISPR activation of ACACA in ferroptosis models |
| What is the role of ACC in platelet function? | Platelet-specific knockout or knock-in mice |
| How do bacterial ACC inhibitors affect viability? | Conditional knockout of acc genes in bacteria |
| What is the impact of ACC isoform switching? | Dual knockout or isoform-specific knock-in in cell lines |
How to Study the acetyl-CoA carboxylase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiometric assay | Incorporation of 14C-bicarbonate into malonyl-CoA | Enzyme kinetics and inhibitor testing |
| Spectrophotometric assay | ADP production or NADH oxidation | High-throughput screening |
| CRISPR knockout screen | Gene essentiality and modifiers of ACC activity | Discovery of regulators |
| Metabolomics (LC-MS) | Malonyl-CoA and acetyl-CoA levels | Pathway flux analysis |
| Lipidomics | Fatty acid composition and lipid peroxidation | Ferroptosis and lipogenesis studies |
| Western blot | ACC phosphorylation and protein levels | Regulation by AMPK and hormones |
| Cryo-EM/X-ray crystallography | Three-dimensional structure | Mechanistic and inhibitor design |
| Platelet aggregation assay | Thrombin-induced aggregation | Anti-platelet drug evaluation |
Biochemical activity assays
Acetyl-CoA carboxylase activity can be measured using radiometric or spectrophotometric assays that monitor the incorporation of radiolabeled bicarbonate into malonyl-CoA or the consumption of ATP. These assays are used to determine kinetic parameters and to test inhibitors such as CP640.186. Coupled enzyme assays can also detect ADP production.
Genetic and CRISPR screens
CRISPR knockout and activation screens can identify genes that modulate acetyl-CoA carboxylase activity or its downstream effects. Pooled screens with malonyl-CoA sensors or lipid stains enable high-throughput discovery of regulators. These approaches are complemented by RNA-seq to profile transcriptional changes.
Metabolomics and lipidomics
Mass spectrometry-based metabolomics quantifies malonyl-CoA, acetyl-CoA, and fatty acid species, providing a direct readout of acetyl-CoA carboxylase activity. Lipidomics further resolves changes in membrane lipid composition and lipid peroxidation products in ferroptosis studies.
Structural and biophysical methods
X-ray crystallography and cryo-EM have revealed the architecture of multi-subunit and multi-domain acetyl-CoA carboxylases, including the fused BC-BCCP enzyme from Chloroflexus aurantiacus. These methods guide inhibitor design and illuminate catalytic mechanisms.
How CRISPR Can Be Used to Study GO:0003989 acetyl-CoA carboxylase activity
Knockout
CRISPR knockout of ACACA or ACACB in cell lines and animal models is used to determine isoform-specific functions in lipogenesis, fatty acid oxidation, and ferroptosis. Knockout of bacterial acc genes validates essentiality and supports antibiotic target validation. Platelet-specific knockout models help dissect the role of ACC in thrombosis.
Point Mutation
Point mutations can be introduced into ACACA or ACACB to mimic or prevent phosphorylation, altering regulation by AMPK. Such models are valuable for studying how specific phosphorylation sites affect enzyme activity and metabolic flux. Mutations in the biotin attachment site can also abolish catalytic activity.
Knock-in
Knock-in of tagged or fluorescent versions of ACACA allows live-cell imaging and proteomic analysis of the enzyme. Knock-in of disease-associated variants can model metabolic disorders. In bacteria, knock-in of mutated acc genes can test inhibitor resistance.
Overexpression
Overexpression of ACACA or ACACB increases malonyl-CoA production and can drive lipogenesis or ferroptosis depending on context. Overexpression models are used to study the consequences of ACC activation in cancer and metabolic cells. Inducible overexpression systems allow temporal control of enzyme levels.
How EDITGENE Supports acetyl-CoA carboxylase activity Research
Researchers studying acetyl-CoA carboxylase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, ferroptosis, or disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional validation of genes in the acetyl-CoA carboxylase pathway.
Contact EDITGENE today to design your custom CRISPR model for acetyl-CoA carboxylase activity research.
Frequently Asked Questions About acetyl-CoA carboxylase activity
What is acetyl-CoA carboxylase activity?
Acetyl-CoA carboxylase activity (GO:0003989) is the molecular function that catalyzes the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA, the first committed step in fatty acid biosynthesis.
What genes are involved in acetyl-CoA carboxylase activity?
The main human genes are ACACA (ACC1) and ACACB (ACC2); in bacteria, multi-subunit genes such as accBC and accDA encode the enzyme components.
What is the reaction catalyzed by acetyl-CoA carboxylase?
The enzyme catalyzes: ATP + acetyl-CoA + HCO3- = ADP + phosphate + malonyl-CoA.
How is acetyl-CoA carboxylase activity regulated?
It is regulated by phosphorylation (e.g., by AMPK), allosteric effectors like citrate and long-chain acyl-CoAs, and hormones such as insulin and glucagon.
What diseases are associated with acetyl-CoA carboxylase activity?
Dysregulation is linked to cancer, obesity, type 2 diabetes, ferroptosis, and thrombosis.
What is the difference between ACC1 and ACC2?
ACC1 (ACACA) is cytosolic and supports fatty acid synthesis, while ACC2 (ACACB) is associated with mitochondria and regulates fatty acid oxidation via malonyl-CoA.
How can I study acetyl-CoA carboxylase activity in the lab?
Common methods include biochemical activity assays, CRISPR knockout or knock-in models, metabolomics, lipidomics, and structural biology.
Is acetyl-CoA carboxylase a drug target?
Yes, it is a target for anti-obesity, anti-diabetic, antibiotic, herbicide, and anti-platelet therapies.
What is the role of biotin in acetyl-CoA carboxylase activity?
Biotin is covalently attached to the biotin carboxyl carrier protein domain and is essential for carboxyl group transfer during catalysis.
Can acetyl-CoA carboxylase activation induce ferroptosis?
Recent studies show that activation of acetyl-CoA carboxylase disrupts iron homeostasis and can drive ferroptosis.
Conclusion
Acetyl-CoA carboxylase activity (GO:0003989) is a fundamental molecular function that links energy metabolism to fatty acid synthesis and oxidation. Its central role in producing malonyl-CoA makes it a critical regulator of lipid homeostasis, cell growth, and stress responses such as ferroptosis. Researchers continue to uncover its structural diversity, regulatory mechanisms, and potential as a therapeutic target across metabolic diseases, cancer, and infectious diseases. With advanced CRISPR models and multi-omics approaches, the field is well positioned to translate these insights into new treatments.
References
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- 2. Brownsey RW et al.. 2006. Regulation of acetyl-CoA carboxylase.. Biochem Soc Trans 34(Pt 2):223-7 PMID: 16545081
- 3. Cronan JE Jr et al.. 2002. Multi-subunit acetyl-CoA carboxylases.. Prog Lipid Res 41(5):407-35 PMID: 12121720
- 4. Octave M et al.. 2021. Acetyl-CoA Carboxylase Inhibitor CP640.186 Increases Tubulin Acetylation and Impairs Thrombin-Induced Platelet Aggregation.. Int J Mol Sci 22(23) PMID: 34884932
- 5. Polyak SW et al.. 2012. Structure, function and selective inhibition of bacterial acetyl-coa carboxylase.. Appl Microbiol Biotechnol 93(3):983-92 PMID: 22183085
- 6. Lane MD et al.. 1979. Hormonal regulation of acetyl-CoA carboxylase activity in the liver cell.. CRC Crit Rev Biochem 7(2):121-41 PMID: 41683
- 7. Shen J et al.. 2024. Chloroflexus aurantiacus acetyl-CoA carboxylase evolves fused biotin carboxylase and biotin carboxyl carrier protein to complete carboxylation activity.. mBio 15(5):e0341423 PMID: 38572988
- 8. Gornicki P et al.. 1993. Wheat acetyl-CoA carboxylase.. Plant Mol Biol 22(3):547-52 PMID: 8101104
