GO:0047655 allyl-alcohol dehydrogenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0047655 (allyl-alcohol dehydrogenase activity) catalyzes the NADP+-dependent oxidation of allyl alcohol to acrolein, a reactive aldehyde.
• The enzyme is a member of the alcohol dehydrogenase (ADH) family and is inhibited by pyrazole, a classic ADH inhibitor.
• Allyl alcohol is a hepatotoxin that requires ADH-mediated bioactivation to acrolein, which depletes glutathione and causes oxidative stress.
• Genetic selection using allyl alcohol has been used to isolate ADH-deficient mutants in yeast, plants, nematodes, and mammalian cells.
• In Aldh2*2 knock-in mice, allyl alcohol exposure triggers systemic aldehyde storm and hepatic ferroptosis.
• Studying GO:0047655 helps researchers understand alcohol metabolism, aldehyde toxicity, and develop CRISPR models for ADH-related diseases.
Description
Allyl-alcohol dehydrogenase activity (GO:0047655) is a molecular function defined as the catalysis of the reaction: allyl alcohol + NADP+ = acrolein + H+ + NADPH. This enzymatic activity belongs to the alcohol dehydrogenase (ADH) family and is responsible for the oxidation of allyl alcohol to the highly reactive aldehyde acrolein. The enzyme utilizes NADP+ as an electron acceptor, distinguishing it from classical NAD+-dependent ADHs. This activity is of significant interest because allyl alcohol is a well-known hepatotoxin that requires metabolic activation by ADH to exert its toxic effects. The resulting acrolein is a potent electrophile that can deplete cellular glutathione and induce oxidative stress, leading to liver injury. Consequently, allyl-alcohol dehydrogenase activity is a critical node in the study of alcohol metabolism, aldehyde detoxification, and xenobiotic-induced toxicity. Researchers have exploited this activity for genetic selection, as cells with reduced ADH activity survive in the presence of allyl alcohol, enabling the isolation of ADH mutants in various organisms. Understanding the molecular mechanism, regulation, and physiological roles of this enzyme is essential for toxicology, pharmacology, and metabolic engineering.
allyl-alcohol dehydrogenase activity At A Glance
| GO ID | GO:0047655 |
|---|---|
| GO term | allyl-alcohol dehydrogenase activity |
| Ontology | molecular_function |
| Synonym | allyl-alcohol:NADP+ oxidoreductase activity |
| Definition | Catalysis of the reaction: allyl alcohol + NADP+ = acrolein + H+ + NADPH. |
| Major function | Oxidation of allyl alcohol to acrolein using NADP+ as cofactor |
| Reaction direction | Reversible; physiological direction may favor oxidation |
| Enzyme class | Oxidoreductase (EC 1.1.1.-) |
| Cofactor | NADP+ (nicotinamide adenine dinucleotide phosphate) |
| Substrate | Allyl alcohol (2-propen-1-ol) |
| Product | Acrolein (2-propenal) |
What Is GO:0047655?
Allyl-alcohol dehydrogenase activity (GO:0047655) is the enzyme activity that catalyzes the chemical reaction: allyl alcohol + NADP+ = acrolein + H+ + NADPH. In this reaction, allyl alcohol is oxidized to acrolein, while NADP+ is reduced to NADPH. The enzyme is also known as allyl-alcohol:NADP+ oxidoreductase. This activity is part of the oxidoreductase class, specifically acting on the CH-OH group of donors with NAD+ or NADP+ as acceptor. It is distinct from other alcohol dehydrogenases due to its preference for NADP+ and its ability to use allyl alcohol as a substrate.
Why Is allyl-alcohol dehydrogenase activity Important in Cell Biology?
Allyl-alcohol dehydrogenase activity is important because it represents a key metabolic step in the bioactivation of allyl alcohol to acrolein, a toxic and reactive aldehyde. This activity is directly linked to hepatotoxicity, as allyl alcohol-induced liver damage depends on its metabolism by ADH. The enzyme also serves as a selectable marker in genetic studies, allowing the isolation of ADH-deficient mutants that are resistant to allyl alcohol. Furthermore, understanding this activity provides insights into alcohol metabolism, aldehyde detoxification pathways, and the mechanisms of oxidative stress-related diseases. In the context of modern biomedical research, allyl-alcohol dehydrogenase activity is relevant for toxicology, drug metabolism, and the development of CRISPR-based models to study ADH function and related disorders.
• Mediates the bioactivation of allyl alcohol to the toxic aldehyde acrolein, a key step in allyl alcohol-induced hepatotoxicity.
• Serves as a target for genetic selection in yeast, plants, nematodes, and mammalian cells to isolate ADH-deficient mutants.
• Contributes to the understanding of alcohol dehydrogenase family evolution and substrate specificity.
• Plays a role in aldehyde detoxification and oxidative stress responses, as acrolein can deplete glutathione.
• Provides a model for studying ferroptosis, as allyl alcohol exposure in Aldh2*2 mice induces hepatic ferroptosis.
• Enables research on metabolic engineering of NADP+-dependent oxidoreductases.
• Helps elucidate the mechanisms of xenobiotic-induced liver injury and potential protective strategies.
• Facilitates the development of CRISPR knockout and knock-in models to study ADH genes in disease contexts.
• Supports the discovery of inhibitors or activators for therapeutic intervention in aldehyde toxicity.
• Aids in the interpretation of genome-wide association studies linking ADH variants to alcohol-related traits.
What Happens During allyl-alcohol dehydrogenase activity?
Substrate Binding and Oxidation
In simple terms: The enzyme grabs allyl alcohol and removes electrons from it.
The catalytic cycle begins with the binding of allyl alcohol and NADP+ to the active site of the enzyme. The enzyme facilitates the transfer of a hydride ion from the alcohol carbon to NADP+, forming NADPH and acrolein. This oxidation step is characteristic of alcohol dehydrogenases, which typically use a zinc ion in the active site to polarize the substrate. The reaction is reversible, but under physiological conditions, the oxidation of allyl alcohol to acrolein is favored due to the rapid removal of acrolein by downstream detoxification pathways.
Acrolein Formation and Reactivity
In simple terms: The product, acrolein, is a highly reactive molecule that can damage cells.
Acrolein is an alpha,beta-unsaturated aldehyde that is highly electrophilic. It can readily react with nucleophilic groups in proteins and DNA, forming adducts that disrupt cellular functions. In the liver, acrolein depletes glutathione, leading to oxidative stress and lipid peroxidation. This reactivity underlies the hepatotoxicity of allyl alcohol, as the formation of acrolein is the critical toxic event. The enzyme's role in producing acrolein makes it a key mediator of allyl alcohol toxicity.
NADP+ Regeneration and Cofactor Balance
In simple terms: The enzyme uses NADP+ and produces NADPH, affecting the cell's redox balance.
The reduction of NADP+ to NADPH by allyl-alcohol dehydrogenase activity contributes to the cellular pool of reducing equivalents. NADPH is essential for reductive biosynthesis and antioxidant defense, including the regeneration of reduced glutathione. However, excessive production of NADPH may also fuel reductive stress. The balance between NADP+ and NADPH is critical for cellular homeostasis, and the activity of this enzyme can influence this balance.
Enzyme Inhibition and Regulation
In simple terms: The enzyme can be blocked by inhibitors like pyrazole, which affects its activity.
Allyl-alcohol dehydrogenase activity is inhibited by pyrazole, a classic inhibitor of alcohol dehydrogenases. This inhibition can prevent the metabolism of allyl alcohol to acrolein, thereby reducing toxicity. The enzyme's activity may also be regulated by substrate availability, cofactor levels, and post-translational modifications. In yeast, mutations in ADH genes confer resistance to allyl alcohol, indicating that the enzyme's activity is subject to genetic regulation.
Key Genes Involved in GO:0047655 allyl-alcohol dehydrogenase activity
The following genes encode enzymes with allyl-alcohol dehydrogenase activity or are directly involved in its metabolic pathway, as evidenced by genetic and biochemical studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| Adh1 | Encodes alcohol dehydrogenase 1, a primary enzyme for allyl alcohol oxidation in yeast and mammals | Used in genetic selection for allyl alcohol resistance; knockout reduces toxicity |
| Adh2 | Encodes alcohol dehydrogenase 2, involved in ethanol metabolism and allyl alcohol oxidation | Mutations confer temperature-conditional allyl alcohol resistance in yeast |
| Adh3 | Encodes alcohol dehydrogenase 3, a mitochondrial enzyme with allyl alcohol dehydrogenase activity | Studied in deermice for allyl alcohol hepatotoxicity |
| Adh4 | Encodes alcohol dehydrogenase 4, contributes to allyl alcohol metabolism | Potential target for CRISPR knockout to study substrate specificity |
| Adh5 | Encodes alcohol dehydrogenase 5 (class III), involved in formaldehyde and allyl alcohol detoxification | Relevant to aldehyde detoxification and oxidative stress |
| Aldh2 | Encodes aldehyde dehydrogenase 2, detoxifies acrolein and other aldehydes | Aldh2*2 knock-in mice show enhanced ferroptosis upon allyl alcohol exposure |
| Xdh | Encodes xanthine dehydrogenase, which can be affected by allyl alcohol treatment | Allyl alcohol alters xanthine dehydrogenase activity in perfused rat liver |
| Adh1 (plant) | Alcohol dehydrogenase in Nicotiana plumbaginifolia | Allyl alcohol selection for lower ADH activity in cultured cells |
| Adh (C. elegans) | Alcohol dehydrogenase in Caenorhabditis elegans | Mutants lacking ADH activity isolated via allyl alcohol resistance |
| Adh (Chinese hamster) | Alcohol dehydrogenase in Chinese hamster somatic cells | ADH mutants resistant to allyl alcohol |
| Adh (deermouse) | Alcohol dehydrogenase in Peromyscus maniculatus | Hepatotoxicity due to allyl alcohol depends on ADH |
| ADH1B | Human alcohol dehydrogenase 1B, with high allyl alcohol oxidation capacity | Genetic variants linked to alcohol metabolism and toxicity |
| ADH1C | Human alcohol dehydrogenase 1C, contributes to allyl alcohol oxidation | Polymorphisms affect alcohol elimination rates |
| ADH4 | Human alcohol dehydrogenase 4, active towards allyl alcohol | Expressed in liver and stomach; potential drug target |
| ADH5 | Human alcohol dehydrogenase 5 (formaldehyde dehydrogenase) | Involved in formaldehyde and acrolein detoxification |
| ADH6 | Human alcohol dehydrogenase 6, poorly characterized | May have allyl alcohol dehydrogenase activity |
| ADH7 | Human alcohol dehydrogenase 7, class IV | Expressed in gastrointestinal tract; role in allyl alcohol metabolism |
| ADHFE1 | Iron-containing alcohol dehydrogenase, not NADP+-dependent | Unlikely to contribute to GO:0047655 |
How Is allyl-alcohol dehydrogenase activity Regulated?
The activity of allyl-alcohol dehydrogenase is regulated at multiple levels. Genetically, mutations in ADH genes can abolish or reduce enzyme activity, as demonstrated by allyl alcohol-resistant mutants in yeast, plants, nematodes, and mammalian cells. In deermice, the hepatotoxicity of allyl alcohol depends on ADH activity, indicating that genetic differences in ADH expression modulate susceptibility. Biochemically, the enzyme is inhibited by pyrazole, which competes with substrate binding. Cofactor availability (NADP+) and the redox state of the cell can also influence enzyme velocity. Additionally, the product acrolein can feedback-inhibit the enzyme or deplete cofactors, though direct evidence for feedback inhibition is limited. Post-translational modifications, such as phosphorylation, may regulate ADH activity, but specific modifications for allyl-alcohol dehydrogenase remain to be fully elucidated. In the context of disease, Aldh2 deficiency alters the metabolic flux of acrolein, indirectly affecting the consequences of allyl-alcohol dehydrogenase activity.
allyl-alcohol dehydrogenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Adh1 | Allyl alcohol hepatotoxicity | Adh1 knockout mouse; allyl alcohol challenge |
| Aldh2 | Aldehyde storm and ferroptosis | Aldh2*2 knock-in mouse; allyl alcohol exposure |
| Adh (deermouse) | Hepatotoxicity depends on ADH | Deermouse strains with varying ADH activity |
| Adh (yeast) | Allyl alcohol resistance | Yeast ADH mutants for genetic selection |
| Adh (C. elegans) | ADH deficiency | C. elegans mutants lacking ADH activity |
Allyl Alcohol-Induced Hepatotoxicity
Allyl alcohol is a potent hepatotoxin that requires metabolic activation by alcohol dehydrogenase to acrolein. Studies in deermice have shown that hepatotoxicity depends on ADH activity, as strains with low ADH are resistant. In perfused rat liver, allyl alcohol treatment affects xanthine dehydrogenase activity, suggesting a link to oxidative stress. The toxicity is characterized by periportal necrosis, glutathione depletion, and lipid peroxidation. This makes allyl-alcohol dehydrogenase activity a critical determinant of allyl alcohol poisoning and a target for protective strategies.
Aldehyde Storm and Ferroptosis
Recent research using Aldh2*2 knock-in mice, which model the human ALDH2*2 polymorphism, demonstrated that allyl alcohol exposure induces a systemic aldehyde storm and extensive hepatic ferroptosis. This highlights the interplay between allyl-alcohol dehydrogenase activity, aldehyde detoxification, and iron-dependent cell death. The study suggests that individuals with impaired ALDH2 function may be more susceptible to allyl alcohol toxicity, with ferroptosis as a key mechanism.
Alcohol Metabolism and Genetic Susceptibility
Alcohol dehydrogenases, including those with allyl-alcohol dehydrogenase activity, are key enzymes in ethanol metabolism. Genetic variants in human ADH genes (e.g., ADH1B, ADH1C) influence alcohol elimination rates and are associated with alcohol-related diseases. While allyl alcohol is not a physiological substrate, the enzyme's ability to oxidize allyl alcohol reflects its broad substrate specificity. Studying these enzymes helps understand individual differences in alcohol metabolism and susceptibility to alcohol-related liver disease.
From allyl-alcohol dehydrogenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does Adh1 knockout protect against allyl alcohol-induced liver injury? | Adh1 knockout mouse (CRISPR/Cas9) |
| What is the effect of a point mutation in the active site on enzyme kinetics? | Point-mutation knock-in of Adh1 (e.g., catalytic residue substitution) |
| How does human ALDH2*2 variant affect allyl alcohol toxicity? | Aldh2*2 knock-in mouse |
| Can tagged ADH be used to study subcellular localization? | Tagged knock-in of Adh1 with GFP or FLAG |
| What is the consequence of ADH overexpression in hepatocytes? | Overexpression of Adh1 via AAV or transgenic mouse |
| Which genes mediate allyl alcohol resistance? | CRISPR library screening in hepatocytes or yeast |
How to Study the allyl-alcohol dehydrogenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH absorbance assay | Enzyme activity via NADPH production | Kinetic characterization of ADH enzymes |
| Allyl alcohol resistance selection | Cell viability in presence of allyl alcohol | Isolation of ADH-deficient mutants |
| CRISPR knockout screening | Gene essentiality or resistance | Identification of genes modulating allyl alcohol toxicity |
| LC-MS metabolomics | Levels of allyl alcohol, acrolein, and metabolites | Profiling aldehyde storm and detoxification |
| Western blot | Protein expression of ADH isoforms | Validation of knockout or overexpression |
| Immunohistochemistry | Tissue localization of ADH | Studying liver zonation of allyl alcohol metabolism |
| RNA-seq | Transcriptional changes upon allyl alcohol exposure | Identifying adaptive responses and toxicity pathways |
| Ferroptosis assays | Lipid peroxidation and iron-dependent cell death | Evaluating hepatic ferroptosis in Aldh2*2 mice |
Enzymatic Assays for Allyl-Alcohol Dehydrogenase Activity
Direct measurement of allyl-alcohol dehydrogenase activity can be performed using spectrophotometric assays that monitor the reduction of NADP+ to NADPH at 340 nm. Liver homogenates or purified enzyme preparations are incubated with allyl alcohol and NADP+, and the increase in absorbance is recorded. This method is useful for characterizing enzyme kinetics, inhibitor effects (e.g., pyrazole), and tissue distribution.
Genetic Selection with Allyl Alcohol
Allyl alcohol is toxic to cells with active ADH, as it is converted to acrolein. This property has been exploited to select for ADH-deficient mutants in yeast, plants, nematodes, and mammalian cells. Cells are plated on medium containing allyl alcohol, and resistant colonies are isolated. This approach is powerful for forward genetics and for validating CRISPR knockout efficiency.
CRISPR Screening and Bioinformatics
Genome-wide CRISPR knockout screens can identify genes that modulate sensitivity to allyl alcohol. Cells are transduced with a lentiviral sgRNA library, treated with allyl alcohol, and surviving cells are sequenced to identify enriched sgRNAs. Bioinformatics analysis reveals candidate genes, including ADH family members and aldehyde detoxification enzymes. This method enables unbiased discovery of pathways linked to allyl-alcohol dehydrogenase activity.
Metabolomics and Aldehyde Profiling
Mass spectrometry-based metabolomics can quantify allyl alcohol, acrolein, and downstream metabolites (e.g., glutathione adducts) in biological samples. This approach provides a comprehensive view of the metabolic flux through allyl-alcohol dehydrogenase and its impact on cellular redox status. It is particularly useful for studying aldehyde storm and ferroptosis in vivo.
How CRISPR Can Be Used to Study GO:0047655 allyl-alcohol dehydrogenase activity
Knockout
CRISPR/Cas9-mediated knockout of ADH genes (e.g., Adh1) can abolish allyl-alcohol dehydrogenase activity, conferring resistance to allyl alcohol toxicity. This approach is used to create isogenic cell lines and animal models to study the role of ADH in allyl alcohol metabolism and liver injury. Knockout models help establish causality between enzyme activity and toxic outcomes.
Point Mutation
Introducing specific point mutations in the active site of ADH (e.g., substituting catalytic residues) via CRISPR base editing or homology-directed repair allows fine-tuning of enzyme activity. Such models are valuable for dissecting the contribution of allyl-alcohol dehydrogenase activity to substrate specificity and inhibitor binding. They also mimic naturally occurring human variants.
Knock-in
Knock-in of human ADH variants or tagged versions (e.g., GFP-ADH) enables real-time tracking of enzyme localization and dynamics. The Aldh2*2 knock-in mouse is a prime example, modeling human ALDH2 deficiency and its impact on allyl alcohol-induced ferroptosis. Knock-in models are essential for translational research.
Overexpression
Overexpression of ADH genes using CRISPR activation (CRISPRa) or transgenic constructs can increase allyl-alcohol dehydrogenase activity, sensitizing cells to allyl alcohol. This is useful for studying dose-dependent toxicity and for screening protective compounds. Overexpression models also help identify downstream effects of acrolein production.
How EDITGENE Supports allyl-alcohol dehydrogenase activity Research
Researchers studying allyl-alcohol dehydrogenase activity-related genes often need to determine whether a candidate gene is causally involved in allyl alcohol metabolism, aldehyde detoxification, or related diseases. EDITGENE provides comprehensive CRISPR-based services to create precisely engineered cell and animal models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for allyl-alcohol dehydrogenase activity research.
Frequently Asked Questions About allyl-alcohol dehydrogenase activity
What is allyl-alcohol dehydrogenase activity?
Allyl-alcohol dehydrogenase activity (GO:0047655) is the enzyme activity that catalyzes the oxidation of allyl alcohol to acrolein using NADP+ as a cofactor, producing NADPH.
What genes are involved in allyl-alcohol dehydrogenase activity?
Genes encoding alcohol dehydrogenases (ADH) such as Adh1, Adh2, Adh3, and Adh5 in various organisms are involved in this activity.
What is the reaction catalyzed by allyl-alcohol dehydrogenase?
The reaction is: allyl alcohol + NADP+ = acrolein + H+ + NADPH.
Why is allyl alcohol toxic to the liver?
Allyl alcohol is toxic because it is metabolized by ADH to acrolein, a reactive aldehyde that depletes glutathione and causes oxidative stress and necrosis.
How is allyl-alcohol dehydrogenase activity measured?
It is typically measured by spectrophotometric assays monitoring NADPH production at 340 nm or by genetic selection using allyl alcohol resistance.
What is the role of ADH in allyl alcohol resistance?
Cells with reduced ADH activity are resistant to allyl alcohol because they cannot convert it to toxic acrolein, allowing selection of ADH mutants.
Can CRISPR be used to study allyl-alcohol dehydrogenase activity?
Yes, CRISPR knockout, knock-in, and overexpression models can be used to manipulate ADH genes and study their role in allyl alcohol metabolism and toxicity.
What diseases are associated with allyl-alcohol dehydrogenase activity?
Allyl alcohol-induced hepatotoxicity, aldehyde storm, and ferroptosis are associated with this activity, particularly in the context of ALDH2 deficiency.
Which organisms have been used to study allyl-alcohol dehydrogenase?
Yeast, Nicotiana plumbaginifolia, Caenorhabditis elegans, Chinese hamster cells, deermice, and mice have been used.
What is the difference between allyl-alcohol dehydrogenase and other alcohol dehydrogenases?
Allyl-alcohol dehydrogenase specifically uses NADP+ and allyl alcohol as substrate, while other ADHs may prefer NAD+ and ethanol.
Conclusion
Allyl-alcohol dehydrogenase activity (GO:0047655) is a specialized oxidoreductase function that converts allyl alcohol to the toxic aldehyde acrolein. Its study has illuminated mechanisms of alcohol metabolism, hepatotoxicity, and aldehyde detoxification. Genetic selection using allyl alcohol has been instrumental in isolating ADH mutants across species, and recent work in Aldh2*2 mice has linked this activity to ferroptosis. Understanding the regulation and physiological roles of this enzyme is crucial for toxicology and disease research. With CRISPR technologies, researchers can now create precise models to dissect the contribution of allyl-alcohol dehydrogenase activity to health and disease.
References
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- 7. Takami Y et al.. 2025. Systemic aldehyde storm induced by allyl alcohol exposure results in extensive hepatic ferroptosis in Aldh2∗2 knock-in mice.. Free Radic Biol Med 239:177-188 PMID: 40744345
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