GO:0019166 trans-2-enoyl-CoA reductase (NADPH) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0019166 describes the NADPH-dependent reduction of trans-2,3-dehydroacyl-CoA to acyl-CoA, a reversible reaction that can also operate in the oxidative direction.
• The enzyme is best known for its role in the fatty acid elongation cycle, where it reduces trans-2-enoyl-CoA intermediates generated by elongases.
• In humans, the TER gene (also known as MECR) encodes a mitochondrial trans-2-enoyl-CoA reductase that is involved in fatty acid elongation and sphingolipid metabolism.
• Mutations in TER/MECR cause nonsyndromic mental retardation by impairing enzyme activity and stability, leading to altered sphingolipid profiles.
• Beyond fatty acid synthesis, trans-2-enoyl-CoA reductase activity participates in phytol degradation in peroxisomes and regulates endoplasmic reticulum calcium homeostasis by inhibiting SERCA2b.
• Prokaryotic and protist homologs, such as those from Treponema denticola and Euglena gracilis, define distinct enzyme families and support biotechnological applications.
Description
trans-2-enoyl-CoA reductase (NADPH) activity (GO:0019166) is a molecular function that catalyzes the reversible reduction of trans-2,3-dehydroacyl-CoA to acyl-CoA using NADPH as the electron donor. This activity is central to the fatty acid elongation cycle, where it reduces the trans-2-enoyl-CoA intermediate produced by fatty acid elongases, thereby enabling successive rounds of carbon chain extension. The reaction is also reversible, allowing the enzyme to function in the oxidative direction during fatty acid degradation or in specialized metabolic pathways. Researchers study this activity because it links lipid synthesis, energy metabolism, and cellular signaling, and because its dysfunction is associated with human disease, including mental retardation and metabolic disorders. The enzyme is found in multiple cellular compartments, including mitochondria, peroxisomes, and the cytosol, and its isoforms exhibit distinct substrate specificities and regulatory roles. Understanding GO:0019166 is therefore essential for dissecting lipid metabolic networks and for developing therapeutic strategies targeting fatty acid elongation and related pathways.
trans-2-enoyl-CoA reductase (NADPH) activity At A Glance
| GO ID | GO:0019166 |
|---|---|
| GO term | trans-2-enoyl-CoA reductase (NADPH) activity |
| Ontology | molecular_function |
| Synonym | acyl-CoA:NADP+ trans-2-oxidoreductase activity; NADPH-dependent trans-2-enoyl-CoA reductase activity; reductase, trans-enoyl coenzyme A |
| Major function | Reduction of trans-2,3-dehydroacyl-CoA to acyl-CoA using NADPH, and the reverse oxidation |
| Reaction | acyl-CoA + NADP+ = trans-2,3-dehydroacyl-CoA + NADPH + H+ |
| Cofactor | NADPH/NADP+ |
| Subcellular locations | Mitochondria, peroxisomes, cytosol |
| Related pathways | Fatty acid elongation, phytol degradation, wax ester fermentation, ER calcium regulation |
What Is GO:0019166?
GO:0019166 is defined as the catalysis of the reaction: acyl-CoA + NADP+ = trans-2,3-dehydroacyl-CoA + NADPH + H+. In other words, it is an oxidoreductase activity that interconverts acyl-CoA and trans-2,3-dehydroacyl-CoA using NADP+/NADPH as a cofactor. The reaction is reversible and can proceed in either the reductive direction (using NADPH to saturate the double bond) or the oxidative direction (using NADP+ to desaturate the acyl chain). This activity is synonymous with acyl-CoA:NADP+ trans-2-oxidoreductase, NADPH-dependent trans-2-enoyl-CoA reductase, and reductase, trans-enoyl coenzyme A.
Why Is trans-2-enoyl-CoA reductase (NADPH) activity Important in Cell Biology?
GO:0019166 is important because it sits at the crossroads of fatty acid synthesis and degradation, influencing membrane lipid composition, energy storage, and signaling. In humans, the TER/MECR enzyme is essential for fatty acid elongation, and its mutation causes nonsyndromic mental retardation with altered sphingolipid profiles. The enzyme also regulates endoplasmic reticulum calcium homeostasis by inhibiting SERCA2b, linking lipid metabolism to calcium signaling. In peroxisomes, it participates in phytol degradation, connecting it to vitamin E and chlorophyll metabolism. In biotechnology, prokaryotic and protist trans-2-enoyl-CoA reductases are studied for biofuel and wax ester production. Thus, understanding this activity has broad implications for human health, metabolic engineering, and basic cell biology.
• Mutations in the human TER/MECR gene cause nonsyndromic mental retardation by impairing enzyme activity and stability.
• The enzyme is a key component of the fatty acid elongation cycle, affecting membrane lipid composition and energy metabolism.
• It regulates endoplasmic reticulum calcium homeostasis by inhibiting the SERCA2b calcium pump.
• It is involved in peroxisomal phytol degradation, linking it to vitamin E and chlorophyll metabolism.
• Prokaryotic and protist homologs are studied for biofuel and wax ester production.
• The enzyme exists as multiple isoforms with distinct subcellular localizations and substrate specificities.
• It is a potential target for metabolic engineering of fatty acid-derived products.
• Its activity is reversible, allowing it to function in both synthetic and degradative pathways.
• Dysregulation of fatty acid elongation is associated with metabolic disorders and cancer.
• The enzyme provides a model for studying structure-function relationships in oxidoreductases.
Molecular Mechanism of trans-2-enoyl-CoA reductase (NADPH) activity
Substrate Binding and Catalysis
In simple terms: The enzyme grabs a trans-2-enoyl-CoA molecule and a NADPH molecule, then transfers a hydride to the double bond to make a saturated acyl-CoA.
The catalytic mechanism involves the binding of trans-2,3-dehydroacyl-CoA and NADPH to the enzyme active site. The enzyme transfers a hydride from NADPH to the beta-carbon of the double bond, while a proton is added to the alpha-carbon, resulting in the formation of acyl-CoA. This reaction is reversible, and the enzyme can also catalyze the oxidation of acyl-CoA to trans-2-enoyl-CoA using NADP+. Structural and kinetic studies of trans-2-enoyl-CoA reductases from various organisms have revealed a conserved catalytic mechanism involving a tyrosine and a lysine residue that stabilize the substrate and facilitate hydride transfer.
Role in Fatty Acid Elongation
In simple terms: During fatty acid elongation, the enzyme removes a double bond from an intermediate, allowing the fatty acid chain to grow longer.
In the fatty acid elongation cycle, trans-2-enoyl-CoA reductase catalyzes the final step by reducing the trans-2-enoyl-CoA intermediate generated by the condensation and dehydration reactions. This reduction is essential for the cycle to proceed, as it provides the saturated acyl-CoA substrate for the next round of elongation. The enzyme cooperates with fatty acid elongases (ELOVL proteins) to determine the chain length and saturation of fatty acids. In humans, the mitochondrial isoform (TER/MECR) is particularly important for the elongation of very long-chain fatty acids and sphingolipids.
Cofactor Specificity and Isoforms
In simple terms: Different versions of the enzyme prefer NADPH over NADH and are found in different parts of the cell.
trans-2-enoyl-CoA reductases are NADPH-dependent, distinguishing them from NADH-dependent enoyl-CoA reductases involved in beta-oxidation. Multiple isoforms exist: a mitochondrial isoform (MECR/TER), a peroxisomal isoform (PECR), and a cytosolic isoform (Cytosolic MECR). These isoforms exhibit different substrate specificities and tissue distributions. For example, the peroxisomal isoform is involved in phytol degradation, while the cytosolic isoform enhances PPARα activity. The mitochondrial isoform is the major one in fatty acid elongation.
Regulation by Metabolic and Signaling Pathways
In simple terms: The enzyme's activity can be turned up or down by cellular signals and metabolic needs.
The activity of trans-2-enoyl-CoA reductase is regulated at multiple levels. Its expression is influenced by metabolic status and transcription factors such as PPARα, which is activated by the cytosolic isoform. The enzyme's activity can also be affected by the availability of NADPH and the redox state of the cell. In the endoplasmic reticulum, the enzyme inhibits SERCA2b, thereby modulating calcium signaling. Additionally, mutations in the TER gene affect enzyme stability and activity, leading to altered sphingolipid metabolism.
Key Genes Involved in GO:0019166 trans-2-enoyl-CoA reductase (NADPH) activity
The following genes and proteins are directly associated with trans-2-enoyl-CoA reductase (NADPH) activity or its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MECR (TER) | Mitochondrial trans-2-enoyl-CoA reductase; catalyzes reduction of trans-2-enoyl-CoA in fatty acid elongation | Mutations cause nonsyndromic mental retardation; target for lipid metabolism studies |
| PECR | Peroxisomal trans-2-enoyl-CoA reductase; involved in phytol degradation and fatty acid metabolism | Links peroxisomal metabolism to vitamin E and chlorophyll degradation |
| Cytosolic MECR | Cytosolic isoform of mitochondrial trans-2-enoyl-CoA reductase; enhances PPARα activity | Regulates lipid signaling and energy homeostasis |
| TDE_0597 (Treponema denticola) | Prokaryotic trans-2-enoyl-CoA reductase | Model for bacterial fatty acid synthesis and biofuel production |
| EgTER1 (Euglena gracilis) | Mitochondrial trans-2-enoyl-CoA reductase involved in wax ester fermentation | Defines a new enzyme family for lipid synthesis; biofuel applications |
| EgTER2 (Euglena gracilis) | Isoform of mitochondrial trans-2-enoyl-CoA reductase | Dispensable for wax ester production under anaerobic conditions |
| ELOVL1-7 | Fatty acid elongases that generate trans-2-enoyl-CoA intermediates | Cooperate with trans-2-enoyl-CoA reductase in fatty acid elongation |
| SERCA2b (ATP2A2) | Calcium pump in endoplasmic reticulum; inhibited by trans-2-enoyl-CoA reductase | Links lipid metabolism to calcium signaling |
| PPARα (PPARA) | Nuclear receptor activated by cytosolic MECR | Regulates lipid metabolism and inflammation |
| ACOX1 | Peroxisomal acyl-CoA oxidase; produces trans-2-enoyl-CoA | Provides substrate for PECR in peroxisomal beta-oxidation |
| HSD17B4 | Peroxisomal multifunctional enzyme; involved in fatty acid oxidation | Related to trans-2-enoyl-CoA metabolism |
| FASN | Fatty acid synthase; produces acyl-CoA precursors | Provides substrates for elongation and reduction |
| SCD | Stearoyl-CoA desaturase; introduces double bonds | Generates trans-2-enoyl-CoA substrates for reduction |
| ACSL | Acyl-CoA synthetase; activates fatty acids to acyl-CoA | Provides acyl-CoA for reduction |
| CPT1 | Carnitine palmitoyltransferase 1; regulates fatty acid entry into mitochondria | Affects substrate availability for mitochondrial MECR |
| SREBP1 | Transcription factor regulating lipogenic genes | Regulates expression of fatty acid elongation enzymes |
| NRF2 | Transcription factor regulating antioxidant response | May regulate PECR expression under oxidative stress |
| HNF4α | Transcription factor regulating lipid metabolism | Potential regulator of MECR expression |
How Is trans-2-enoyl-CoA reductase (NADPH) activity Regulated?
The activity of trans-2-enoyl-CoA reductase is regulated at transcriptional, post-transcriptional, and metabolic levels. The cytosolic isoform enhances PPARα activity, which in turn regulates lipid metabolism genes. The enzyme's activity depends on NADPH availability and the cellular redox state. In the endoplasmic reticulum, it modulates calcium signaling by inhibiting SERCA2b, and this inhibition may be regulated by calcium and lipid levels. Mutations in the TER gene affect enzyme stability, leading to altered sphingolipid profiles. Additionally, the expression of PECR may be influenced by oxidative stress and peroxisome proliferator-activated receptors.
trans-2-enoyl-CoA reductase (NADPH) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TER/MECR | Nonsyndromic mental retardation | Knockout or point-mutation in neuronal cell lines; patient-derived iPSCs |
| MECR | Metabolic syndrome, dyslipidemia | Overexpression or knockout in hepatocytes; PPARα reporter assays |
| PECR | Peroxisomal disorders, phytol accumulation | Knockout in fibroblasts; phytol degradation assays |
| SERCA2b (ATP2A2) | ER calcium dysregulation, heart failure | Co-culture with MECR-overexpressing cells; calcium imaging |
| ELOVL proteins | Cancer, metabolic disorders | Knockout or knockdown in cancer cell lines; lipidomics |
Nonsyndromic Mental Retardation
Mutations in the TER gene (also known as MECR) cause nonsyndromic mental retardation by impairing the enzyme's activity and stability, leading to changes in sphingolipid profiles. This highlights the critical role of trans-2-enoyl-CoA reductase in brain development and function.
Metabolic Disorders
Dysregulation of fatty acid elongation, in which trans-2-enoyl-CoA reductase plays a key role, is associated with metabolic disorders such as obesity, insulin resistance, and dyslipidemia. The cytosolic isoform enhances PPARα activity, which is a therapeutic target for metabolic diseases.
Calcium Signaling and ER Stress
Trans-2-enoyl-CoA reductase limits calcium accumulation in the endoplasmic reticulum by inhibiting the SERCA2b calcium pump. This links the enzyme to calcium homeostasis and potentially to diseases involving ER stress, such as neurodegeneration and diabetes.
Peroxisomal Disorders
The peroxisomal isoform PECR is involved in phytol degradation, and its dysfunction may contribute to peroxisomal disorders characterized by accumulation of very long-chain fatty acids and phytanic acid.
From trans-2-enoyl-CoA reductase (NADPH) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MECR affect fatty acid elongation? | MECR knockout cell lines (e.g., HEK293, HeLa) followed by lipidomics |
| How does a patient mutation affect enzyme stability? | Point-mutation knock-in of TER mutation in cell lines; Western blot and activity assays |
| Can cytosolic MECR enhance PPARα activity? | Overexpression of cytosolic MECR in hepatocytes; PPARα reporter assay |
| Does PECR deficiency impair phytol degradation? | PECR knockout in peroxisome-competent cells; GC-MS analysis of phytol metabolites |
| Does trans-2-enoyl-CoA reductase regulate ER calcium? | Tagged knock-in of MECR with calcium sensor; live-cell imaging |
| Can prokaryotic trans-2-enoyl-CoA reductase be used for biofuel production? | Heterologous expression in E. coli; fatty alcohol production assays |
How to Study the trans-2-enoyl-CoA reductase (NADPH) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH oxidation assay | Enzyme activity (reduction of trans-2-enoyl-CoA) | Kinetic characterization of purified enzyme |
| LC-MS lipidomics | Fatty acid and sphingolipid composition | Assessing impact of MECR knockout on lipid profiles |
| Co-immunoprecipitation | Protein-protein interactions | Identifying binding partners like SERCA2b |
| Calcium imaging | Intracellular calcium dynamics | Evaluating ER calcium regulation by MECR |
| Western blot | Protein expression and stability | Analyzing mutant TER stability |
| qRT-PCR | mRNA expression levels | Measuring transcriptional regulation of MECR/PECR |
| CRISPR knockout screening | Gene essentiality and pathway dependencies | Identifying synthetic lethal interactions with MECR loss |
| Metabolite profiling (GC-MS) | Phytol degradation intermediates | Studying PECR function in peroxisomes |
Enzymatic Activity Assays
Direct measurement of trans-2-enoyl-CoA reductase activity can be performed using spectrophotometric assays that monitor the oxidation of NADPH at 340 nm. These assays use trans-2-enoyl-CoA substrates and are suitable for purified enzymes or cell lysates. Alternatively, coupled assays with fatty acid elongases can measure the reduction step in the context of the elongation cycle.
Lipidomics and Metabolomics
Mass spectrometry-based lipidomics can quantify changes in fatty acid and sphingolipid profiles upon modulation of trans-2-enoyl-CoA reductase expression or activity. This approach is useful for identifying downstream effects on membrane composition and signaling lipids.
Protein-Protein Interaction Studies
Co-immunoprecipitation and proximity ligation assays can reveal interactions between trans-2-enoyl-CoA reductase and other proteins such as SERCA2b or elongases. These methods help elucidate regulatory mechanisms and functional complexes.
Calcium Imaging
Live-cell calcium imaging using fluorescent indicators (e.g., Fura-2, GCaMP) can assess the impact of trans-2-enoyl-CoA reductase on endoplasmic reticulum calcium levels and SERCA2b activity. This method is particularly relevant for studying the enzyme's role in calcium signaling.
How CRISPR Can Be Used to Study GO:0019166 trans-2-enoyl-CoA reductase (NADPH) activity
Knockout
CRISPR knockout of MECR or PECR can be used to study loss-of-function phenotypes, such as impaired fatty acid elongation, altered sphingolipid profiles, and disrupted calcium homeostasis. Knockout cell lines are valuable for validating the enzyme's role in metabolic pathways and for identifying compensatory mechanisms.
Point Mutation
Introducing patient-specific point mutations (e.g., in TER) via CRISPR knock-in allows researchers to study the molecular consequences of disease-associated variants on enzyme activity and stability. This approach can reveal structure-function relationships and guide therapeutic development.
Knock-in
Tagged knock-in of trans-2-enoyl-CoA reductase (e.g., with GFP or HA) enables live-cell imaging, localization studies, and proteomic analysis of interacting partners. Knock-in of reporter genes under the endogenous promoter can also monitor expression dynamics.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of MECR/PECR can be used to study gain-of-function effects, such as enhanced fatty acid elongation, increased PPARα activity, or altered calcium signaling. Overexpression models are useful for identifying downstream targets and potential therapeutic benefits.
How EDITGENE Supports trans-2-enoyl-CoA reductase (NADPH) activity Research
Researchers studying trans-2-enoyl-CoA reductase (NADPH) activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, calcium signaling, or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and overexpression.
Contact EDITGENE today to design your custom CRISPR model for trans-2-enoyl-CoA reductase (NADPH) activity research.
Frequently Asked Questions About trans-2-enoyl-CoA reductase (NADPH) activity
What is trans-2-enoyl-CoA reductase (NADPH) activity?
It is a molecular function (GO:0019166) that catalyzes the reversible reduction of trans-2,3-dehydroacyl-CoA to acyl-CoA using NADPH as a cofactor.
What genes are involved in trans-2-enoyl-CoA reductase (NADPH) activity?
Key genes include MECR (TER), PECR, and cytosolic MECR in humans, as well as prokaryotic and protist homologs like TDE_0597 and EgTER1.
What is the role of MECR in fatty acid elongation?
MECR encodes the mitochondrial trans-2-enoyl-CoA reductase that reduces trans-2-enoyl-CoA intermediates during fatty acid elongation, enabling chain extension.
How is trans-2-enoyl-CoA reductase related to mental retardation?
Mutations in the TER/MECR gene impair enzyme activity and stability, leading to altered sphingolipid profiles and nonsyndromic mental retardation.
Does trans-2-enoyl-CoA reductase regulate calcium signaling?
Yes, it inhibits the SERCA2b calcium pump in the endoplasmic reticulum, thereby limiting calcium accumulation.
What is the difference between MECR and PECR?
MECR is mitochondrial and involved in fatty acid elongation, while PECR is peroxisomal and participates in phytol degradation and peroxisomal beta-oxidation.
Can trans-2-enoyl-CoA reductase be used for biofuel production?
Prokaryotic and protist homologs are studied for biofuel and wax ester production due to their ability to reduce trans-2-enoyl-CoA.
What diseases are associated with trans-2-enoyl-CoA reductase dysfunction?
Nonsyndromic mental retardation, metabolic disorders, and peroxisomal disorders have been linked to dysfunction of this enzyme.
How can I study trans-2-enoyl-CoA reductase activity in the lab?
Common methods include NADPH oxidation assays, lipidomics, calcium imaging, and CRISPR knockout models.
What CRISPR models are available for studying trans-2-enoyl-CoA reductase?
EDITGENE offers knockout, point mutation knock-in, tagged knock-in, and overexpression models for MECR, PECR, and related genes.
Conclusion
trans-2-enoyl-CoA reductase (NADPH) activity (GO:0019166) is a fundamental enzymatic function in fatty acid metabolism, with critical roles in fatty acid elongation, phytol degradation, calcium signaling, and disease. Its dysfunction is linked to mental retardation and metabolic disorders, making it a valuable target for both basic research and therapeutic development. Advances in CRISPR-based models and lipidomics will continue to illuminate its mechanisms and potential applications.
References
- 1. Gloerich J et al.. 2006. Peroxisomal trans-2-enoyl-CoA reductase is involved in phytol degradation.. FEBS Lett 580(8):2092-6 PMID: 16546181
- 2. Uchida Y et al.. 2021. Trans-2-enoyl-CoA reductase limits Ca(2+) accumulation in the endoplasmic reticulum by inhibiting the Ca(2+) pump SERCA2b.. J Biol Chem 296:100310 PMID: 33482198
- 3. Tucci S et al.. 2007. A novel prokaryotic trans-2-enoyl-CoA reductase from the spirochete Treponema denticola.. FEBS Lett 581(8):1561-6 PMID: 17382934
- 4. Hoffmeister M et al.. 2005. Mitochondrial trans-2-enoyl-CoA reductase of wax ester fermentation from Euglena gracilis defines a new family of enzymes involved in lipid synthesis.. J Biol Chem 280(6):4329-38 PMID: 15569691
- 5. Kato R et al.. 2024. Catalytic mechanism of trans-2-enoyl-CoA reductases in the fatty acid elongation cycle and its cooperative action with fatty acid elongases.. J Biol Chem 300(2):105656 PMID: 38224948
- 6. Kim DG et al.. 2014. A Novel Cytosolic Isoform of Mitochondrial Trans-2-Enoyl-CoA Reductase Enhances Peroxisome Proliferator-Activated Receptor α Activity.. Endocrinol Metab (Seoul) 29(2):185-94 PMID: 25031892
- 7. Abe K et al.. 2013. Mutation for nonsyndromic mental retardation in the trans-2-enoyl-CoA reductase TER gene involved in fatty acid elongation impairs the enzyme activity and stability, leading to change in sphingolipid profile.. J Biol Chem 288(51):36741-9 PMID: 24220030
- 8. Tomiyama T et al.. 2019. A major isoform of mitochondrial trans-2-enoyl-CoA reductase is dispensable for wax ester production in Euglena gracilis under anaerobic conditions.. PLoS One 14(1):e0210755 PMID: 30650145
