GO:0047956 glycerol dehydrogenase (NADP+) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0047956 describes the molecular function of glycerol dehydrogenase (NADP+) activity, which catalyzes the reversible oxidation of glycerol to D-glyceraldehyde using NADP+ as the electron acceptor.
• This activity is distinct from NAD+-dependent glycerol dehydrogenases and is found across fungi, bacteria, and mammals, including Aspergillus nidulans, Gluconobacter oxydans, Klebsiella pneumoniae, and rabbit skeletal muscle.
• In Aspergillus nidulans, the NADP+-dependent glycerol dehydrogenase encoded by gldB is essential for osmotolerance, linking this activity to stress adaptation.
• The enzyme from Gluconobacter oxydans has been characterized as a recombinant protein and applied in the production of L-glyceraldehyde, demonstrating biotechnological potential.
• NADP+-dependent glycerol dehydrogenase activity contributes to glycerol catabolism and reductive glycerol metabolism in organisms such as Aspergillus nidulans and Klebsiella pneumoniae.
• Researchers study this activity using enzyme assays, knockout mutants, heterologous expression, and structural analysis to understand its roles in metabolism and stress responses.
Description
Glycerol dehydrogenase (NADP+) activity, classified under GO:0047956, is a molecular function that catalyzes the reversible conversion of glycerol to D-glyceraldehyde with the concomitant reduction of NADP+ to NADPH. This activity is widely distributed across biological kingdoms, having been identified in filamentous fungi such as Aspergillus nidulans and Mucor circinelloides, bacteria such as Gluconobacter oxydans and Klebsiella pneumoniae, and mammalian tissues including rabbit skeletal muscle. The enzyme provides an alternative route for glycerol utilization and plays a critical role in cellular redox balance and osmoadaptation. Researchers are interested in GO:0047956 because it represents a key entry point into glycerol metabolism, a central hub connecting carbohydrate and lipid metabolism, stress responses, and industrial biotechnology. In Aspergillus nidulans, the NADP+-dependent glycerol dehydrogenase encoded by gldB is essential for osmotolerance, highlighting its importance in adaptation to high-osmolarity environments. In Gluconobacter oxydans, the enzyme has been exploited for the stereospecific production of L-glyceraldehyde, a valuable chiral building block. Understanding the regulation and catalytic properties of this activity can inform metabolic engineering and drug discovery efforts targeting glycerol metabolism. Despite its importance, the NADP+-dependent glycerol dehydrogenase remains less studied than its NAD+-dependent counterparts, and its physiological roles in many organisms are still being elucidated. This article synthesizes the current knowledge on GO:0047956, covering its definition, mechanism, key genes, disease relevance, and research methods, with the aim of supporting both fundamental and applied studies.
glycerol dehydrogenase (NADP+) activity At A Glance
| GO ID | GO:0047956 |
|---|---|
| GO term | glycerol dehydrogenase (NADP+) activity |
| Ontology | molecular_function |
| Synonym | glycerol dehydrogenase [NADP+] activity; glycerol:NADP+ oxidoreductase activity |
| Definition | Catalysis of the reaction: glycerol + NADP+ = D-glyceraldehyde + NADPH. |
| Major function | Oxidation of glycerol to D-glyceraldehyde using NADP+ as cofactor |
| Cofactor | NADP+ (nicotinamide adenine dinucleotide phosphate) |
| Substrate | Glycerol |
| Product | D-glyceraldehyde and NADPH |
| Reaction direction | Reversible; can also reduce D-glyceraldehyde to glycerol with NADPH |
| Organisms | Fungi (Aspergillus nidulans, Mucor circinelloides), bacteria (Gluconobacter oxydans, Klebsiella pneumoniae), mammals (rabbit skeletal muscle) |
What Is GO:0047956?
GO:0047956, glycerol dehydrogenase (NADP+) activity, is defined as the catalysis of the reaction: glycerol + NADP+ = D-glyceraldehyde + NADPH. In other words, it is an oxidoreductase that transfers electrons from glycerol to NADP+, producing D-glyceraldehyde and the reduced cofactor NADPH. This activity is synonymous with glycerol dehydrogenase [NADP+] activity and glycerol:NADP+ oxidoreductase activity. It is a molecular function term in the Gene Ontology, distinguishing it from NAD+-dependent glycerol dehydrogenases by its strict preference for NADP+ as the electron acceptor.
Why Is glycerol dehydrogenase (NADP+) activity Important in Cell Biology?
Glycerol dehydrogenase (NADP+) activity is important because it provides a metabolic route for glycerol utilization and contributes to cellular redox homeostasis by generating NADPH. In Aspergillus nidulans, this activity is essential for osmotolerance, enabling growth under high-osmolarity conditions. In biotechnology, the enzyme from Gluconobacter oxydans is used for the production of L-glyceraldehyde, a chiral intermediate for pharmaceuticals and fine chemicals. Additionally, the activity is implicated in reductive glycerol metabolism in Klebsiella pneumoniae, where it supports the conversion of glycerol to value-added products. Understanding this activity can therefore inform studies on stress adaptation, metabolic engineering, and the development of biocatalysts.
• Provides an alternative route for glycerol catabolism, linking glycerol to central carbon metabolism.
• Generates NADPH, contributing to cellular redox balance and biosynthetic reactions.
• Essential for osmotolerance in Aspergillus nidulans, enabling survival in high-salt or high-sugar environments.
• Enables the biotechnological production of L-glyceraldehyde, a valuable chiral building block.
• Participates in reductive glycerol metabolism in Klebsiella pneumoniae, relevant for industrial glycerol conversion.
• Distinct from NAD+-dependent glycerol dehydrogenases, offering a target for selective inhibition or engineering.
• Found in mammals, suggesting potential roles in glycerol metabolism in skeletal muscle and other tissues.
• Inducible by D-galacturonate in Aspergillus nidulans, linking it to pectin degradation pathways.
• Its activity can be modulated by divalent cations in some organisms, as shown for Klebsiella pneumoniae.
• Serves as a model for studying NADP+ specificity in oxidoreductases.
Molecular Mechanism of glycerol dehydrogenase (NADP+) activity
Substrate binding and specificity
In simple terms: The enzyme grabs glycerol and NADP+ together, positioning them for a chemical reaction.
Glycerol dehydrogenase (NADP+) binds glycerol and NADP+ in a ordered or random manner, forming a ternary complex. The enzyme exhibits strict specificity for NADP+ over NAD+, as demonstrated in the purified enzyme from rabbit skeletal muscle and the recombinant enzyme from Gluconobacter oxydans. The active site accommodates the three-carbon glycerol molecule, orienting the C2 hydroxyl for hydride transfer to NADP+.
Catalytic mechanism and hydride transfer
In simple terms: A hydride ion is removed from glycerol and transferred to NADP+, turning glycerol into D-glyceraldehyde.
The catalytic mechanism involves the oxidation of the secondary alcohol group of glycerol, with a hydride ion transferred from the C2 carbon of glycerol to the nicotinamide ring of NADP+. This results in the formation of D-glyceraldehyde and NADPH. The reaction is reversible, and the enzyme can also catalyze the reduction of D-glyceraldehyde to glycerol using NADPH. The equilibrium favors glycerol oxidation under physiological conditions in some organisms.
Cofactor requirements and metal ion effects
In simple terms: The enzyme needs NADP+ to work, and in some bacteria, metal ions can affect its stability.
NADP+ is an absolute requirement for the oxidative direction of the reaction. In Klebsiella pneumoniae, the glycerol dehydrogenase is inactivated by certain treatments, and divalent cations such as Zn2+ or Mn2+ can influence its activity or stability. However, the NADP+-dependent enzyme from Aspergillus nidulans and Gluconobacter oxydans does not appear to require metal ions for catalysis, distinguishing it from some NAD+-dependent glycerol dehydrogenases.
Regulation and induction
In simple terms: The enzyme's production can be turned on by specific sugars or stress conditions.
In Aspergillus nidulans, the NADP+-dependent glycerol dehydrogenase is inducible by D-galacturonate, suggesting a role in pectin catabolism. The gldB gene, encoding this activity, is essential for osmotolerance, and its expression is likely regulated by osmotic stress signaling pathways. In Mucor circinelloides, multiple glycerol dehydrogenase activities are present, and their regulation may depend on growth conditions. In Klebsiella pneumoniae, overexpression of an aldehyde dehydrogenase stimulates reductive glycerol metabolism, indirectly affecting glycerol dehydrogenase flux.
Physiological role in glycerol catabolism
In simple terms: This enzyme helps cells break down glycerol to use it for energy or building blocks.
Glycerol dehydrogenase (NADP+) activity participates in glycerol catabolism by converting glycerol to D-glyceraldehyde, which can be further metabolized to glycolytic intermediates. In Aspergillus nidulans, this pathway is one of several routes for glycerol utilization, and the NADP+-dependent enzyme is particularly important under conditions where NADP+ is abundant. In Klebsiella pneumoniae, the enzyme contributes to both oxidative and reductive glycerol metabolism, depending on the redox state of the cell.
Key Genes Involved in GO:0047956 glycerol dehydrogenase (NADP+) activity
The following genes and proteins are directly associated with glycerol dehydrogenase (NADP+) activity or its regulation, as reported in the literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| gldB (Aspergillus nidulans) | Encodes NADP+-dependent glycerol dehydrogenase essential for osmotolerance | Model for studying osmoadaptation and glycerol metabolism in fungi |
| gldA (Aspergillus nidulans) | NADP+-dependent glycerol dehydrogenase inducible by D-galacturonate | Used to study induction by pectin-derived sugars |
| gldB (Mucor circinelloides) | One of multiple glycerol dehydrogenase activities | Investigated for glycerol metabolism diversity in zygomycetes |
| gldA (Gluconobacter oxydans) | Recombinant NADP-dependent glycerol dehydrogenase | Applied in L-glyceraldehyde production |
| dhaD (Klebsiella pneumoniae) | Glycerol dehydrogenase involved in glycerol metabolism | Studied for reductive glycerol conversion and metal ion effects |
| Gld (rabbit skeletal muscle) | NADP+-dependent glycerol dehydrogenase purified from muscle | Provides mammalian model for enzyme kinetics and structure |
| aldA (Klebsiella pneumoniae) | Aldehyde dehydrogenase that stimulates reductive glycerol metabolism | Overexpression enhances glycerol dehydrogenase flux |
| gldA (Escherichia coli) | NAD+-dependent glycerol dehydrogenase (not NADP+) | Used as a comparison for cofactor specificity studies |
| gldB (Aspergillus nidulans) homologs | Putative NADP+-dependent glycerol dehydrogenases in other fungi | Targets for comparative genomics and functional analysis |
| GPD1 (Saccharomyces cerevisiae) | Glycerol-3-phosphate dehydrogenase (NAD+), not GO:0047956 | Often confused with NADP+-dependent glycerol dehydrogenase; used as a negative control |
| GUT1 (Saccharomyces cerevisiae) | Glycerol kinase, upstream of glycerol dehydrogenase | Studied in context of glycerol catabolism |
| GUT2 (Saccharomyces cerevisiae) | Glycerol-3-phosphate dehydrogenase, mitochondrial | Related to glycerol metabolism but distinct from GO:0047956 |
| dhaK (Klebsiella pneumoniae) | Dihydroxyacetone kinase, downstream of glycerol dehydrogenase | Links glycerol dehydrogenase to central metabolism |
| gldA (Bacillus subtilis) | NAD+-dependent glycerol dehydrogenase | Model for cofactor specificity engineering |
| GldA (Clostridium acetobutylicum) | Glycerol dehydrogenase involved in solventogenesis | Studied for biofuel production |
| Gld (Drosophila melanogaster) | Putative glycerol dehydrogenase | Genetic model for glycerol metabolism |
| Gld (Caenorhabditis elegans) | Putative glycerol dehydrogenase | Model for stress response and aging |
| Gld (Mus musculus) | Putative NADP+-dependent glycerol dehydrogenase | Mammalian model for metabolic studies |
How Is glycerol dehydrogenase (NADP+) activity Regulated?
The expression and activity of glycerol dehydrogenase (NADP+) are regulated at multiple levels. In Aspergillus nidulans, the gldB gene is essential for osmotolerance, and its transcription is likely induced by osmotic stress via the high-osmolarity glycerol (HOG) pathway, although direct evidence is not provided in the cited literature. The enzyme is also inducible by D-galacturonate, indicating regulation by carbon source availability. In Klebsiella pneumoniae, reductive glycerol metabolism can be stimulated by overexpression of an aldehyde dehydrogenase, suggesting that flux through glycerol dehydrogenase is influenced by the redox balance and the availability of downstream enzymes. Additionally, divalent cations such as Zn2+ can inactivate the Klebsiella pneumoniae enzyme, providing a potential post-translational regulatory mechanism. In Mucor circinelloides, multiple glycerol dehydrogenase activities are present, and their differential regulation may depend on growth phase and substrate.
glycerol dehydrogenase (NADP+) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| gldB (Aspergillus nidulans) | Osmotolerance and stress adaptation | Knockout mutants for osmolarity sensitivity assays |
| Gld (rabbit skeletal muscle) | Muscle glycerol metabolism | Enzyme kinetics and tissue-specific expression |
| dhaD (Klebsiella pneumoniae) | Reductive glycerol metabolism | Overexpression and knockout for flux analysis |
| gldA (Gluconobacter oxydans) | Biotechnological production of L-glyceraldehyde | Recombinant expression and biocatalysis |
| gldA (Aspergillus nidulans) | D-galacturonate induction | Induction studies and gene deletion |
Glycerol dehydrogenase (NADP+) activity in metabolic disorders
Glycerol metabolism is linked to obesity, diabetes, and fatty liver disease, as glycerol serves as a substrate for gluconeogenesis and lipid synthesis. The NADP+-dependent glycerol dehydrogenase from rabbit skeletal muscle suggests a role in muscle glycerol utilization, which may be relevant to insulin resistance and exercise physiology. However, direct evidence linking mutations in this enzyme to human metabolic disorders is currently lacking, and further research is needed to establish causality.
Role in fungal pathogenesis and osmotolerance
In Aspergillus nidulans, the NADP+-dependent glycerol dehydrogenase encoded by gldB is essential for osmotolerance, a trait that contributes to the survival of pathogenic fungi in host environments. While Aspergillus nidulans is not a major human pathogen, the principle extends to other fungi such as Aspergillus fumigatus, where osmoadaptation is important for virulence. Targeting this activity could therefore be explored for antifungal drug development, although no direct clinical studies are cited here.
Biotechnological and industrial relevance to disease
The enzyme from Gluconobacter oxydans is used to produce L-glyceraldehyde, a chiral precursor for pharmaceuticals. This biotransformation is relevant to the synthesis of drugs for metabolic and infectious diseases, but it does not directly implicate the enzyme in human disease. Similarly, Klebsiella pneumoniae glycerol dehydrogenase is studied for industrial glycerol conversion, not for pathogenicity.
From glycerol dehydrogenase (NADP+) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of gldB affect osmotolerance? | Knockout of gldB in Aspergillus nidulans |
| What is the substrate specificity of the enzyme? | Point mutations in the active site of recombinant GldA from Gluconobacter oxydans |
| Can the enzyme be redirected to produce novel chiral alcohols? | Knock-in of mutant gldA into E. coli or Gluconobacter |
| How does the enzyme localize in muscle cells? | Tagged knock-in of Gld with GFP in rabbit or mouse myoblasts |
| Does overexpression of gldB enhance osmotolerance? | Overexpression of gldB in Aspergillus nidulans |
| What is the role of divalent cations in enzyme activity? | Site-directed mutagenesis of metal-binding residues in Klebsiella pneumoniae dhaD |
How to Study the glycerol dehydrogenase (NADP+) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH absorbance assay | Enzyme activity via NADPH production at 340 nm | Kinetic characterization of purified enzyme |
| RT-qPCR | mRNA expression levels of gldB | Induction studies under different carbon sources |
| Heterologous expression in E. coli | Production of recombinant enzyme | Biochemical and structural studies |
| Gene knockout | Loss-of-function phenotype | Osmotolerance and metabolic flux analysis |
| Site-directed mutagenesis | Role of specific residues in catalysis | Mechanistic studies and cofactor specificity |
| Protein purification | Isolation of active enzyme | Crystallography and kinetics |
| Metabolic flux analysis | Carbon flow through glycerol metabolism | Industrial strain engineering |
| Inductively coupled plasma mass spectrometry | Metal ion content of enzyme | Cofactor requirement analysis |
Enzymatic activity assays
The most direct method to study glycerol dehydrogenase (NADP+) activity is a spectrophotometric assay monitoring NADPH formation at 340 nm. This assay has been used to characterize the enzyme from Aspergillus nidulans, Gluconobacter oxydans, Klebsiella pneumoniae, and rabbit skeletal muscle. The assay can be performed with crude cell extracts or purified enzyme, and kinetic parameters such as Km and Vmax can be determined.
Gene expression analysis
To study regulation, quantitative RT-PCR or RNA-seq can be used to measure gldB mRNA levels under different conditions, such as osmotic stress or D-galacturonate induction. This approach has been applied in Aspergillus nidulans to show induction by D-galacturonate and in Mucor circinelloides to analyze multiple glycerol dehydrogenase activities.
Heterologous expression and purification
Recombinant expression in E. coli or other hosts allows the production of large quantities of enzyme for biochemical and structural studies. The Gluconobacter oxydans enzyme was successfully expressed and characterized as a recombinant protein. Purification typically involves affinity tags or ion-exchange chromatography, followed by activity assays.
Genetic knockout and complementation
Knockout mutants are powerful tools to assess the physiological role of the enzyme. In Aspergillus nidulans, deletion of gldB resulted in loss of osmotolerance, demonstrating its essential function. Complementation with the wild-type gene restores the phenotype, confirming causality. Similar approaches can be used in other organisms.
How CRISPR Can Be Used to Study GO:0047956 glycerol dehydrogenase (NADP+) activity
Knockout
CRISPR-Cas9 knockout of gldB or its homologs can be used to create loss-of-function mutants to study the role of glycerol dehydrogenase (NADP+) activity in osmotolerance, glycerol catabolism, and stress responses. In Aspergillus nidulans, gldB knockout strains are sensitive to high osmolarity, providing a robust phenotype for genetic screens. Similar knockouts can be generated in other fungi or bacteria to assess metabolic flux.
Point Mutation
CRISPR-mediated point mutations can be introduced into the active site of glycerol dehydrogenase to alter substrate specificity or cofactor preference. For example, mutating residues involved in NADP+ binding could switch specificity to NAD+, as has been explored for other oxidoreductases. Such mutants are valuable for understanding the molecular basis of NADP+ dependence and for engineering enzymes with tailored properties.
Knock-in
Knock-in of a tagged version of the enzyme (e.g., GFP or FLAG) allows visualization of its subcellular localization and interaction partners. This approach can be used to determine whether the enzyme localizes to the cytoplasm, mitochondria, or other compartments in response to osmotic stress. Knock-in of mutant alleles can also be used to test the effect of specific amino acid changes on enzyme function in vivo.
Overexpression
CRISPR activation (CRISPRa) or traditional overexpression constructs can be used to increase the expression of glycerol dehydrogenase (NADP+) to study its impact on glycerol metabolism and osmotolerance. Overexpression of gldB in Aspergillus nidulans might enhance osmotolerance, while overexpression in Klebsiella pneumoniae could increase reductive glycerol flux. This approach is also useful for biotechnological applications, such as improving L-glyceraldehyde production.
How EDITGENE Supports glycerol dehydrogenase (NADP+) activity Research
Researchers studying glycerol dehydrogenase (NADP+) activity-related genes often need to determine whether a candidate gene is causally involved in a specific metabolic or stress-response pathway. This requires precise genetic manipulation, such as knockout, point mutation, knock-in, or overexpression, followed by functional assays. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate such studies, from cell model generation to library screening and bioinformatics analysis.
Contact EDITGENE today to design your custom CRISPR model for glycerol dehydrogenase (NADP+) activity research.
Frequently Asked Questions About glycerol dehydrogenase (NADP+) activity
What is glycerol dehydrogenase (NADP+) activity?
It is a molecular function defined by GO:0047956 that catalyzes the reversible oxidation of glycerol to D-glyceraldehyde using NADP+ as the electron acceptor, producing NADPH.
What genes are involved in glycerol dehydrogenase (NADP+) activity?
Key genes include gldB in Aspergillus nidulans, gldA in Gluconobacter oxydans, dhaD in Klebsiella pneumoniae, and the Gld gene in rabbit skeletal muscle.
What is the difference between NAD+ and NADP+ dependent glycerol dehydrogenase?
NADP+-dependent glycerol dehydrogenase (GO:0047956) strictly uses NADP+ as a cofactor, while NAD+-dependent enzymes use NAD+. They are encoded by different genes and have distinct physiological roles.
Why is glycerol dehydrogenase (NADP+) important for osmotolerance?
In Aspergillus nidulans, the NADP+-dependent glycerol dehydrogenase encoded by gldB is essential for osmotolerance, enabling growth under high-osmolarity conditions.
How is glycerol dehydrogenase (NADP+) activity measured?
It is typically measured by a spectrophotometric assay monitoring NADPH formation at 340 nm, using glycerol and NADP+ as substrates.
What organisms have glycerol dehydrogenase (NADP+) activity?
It has been found in fungi (Aspergillus nidulans, Mucor circinelloides), bacteria (Gluconobacter oxydans, Klebsiella pneumoniae), and mammals (rabbit skeletal muscle).
Can glycerol dehydrogenase (NADP+) be used in biotechnology?
Yes, the enzyme from Gluconobacter oxydans is used for the production of L-glyceraldehyde, a chiral building block for pharmaceuticals.
What are the substrates and products of GO:0047956?
The substrates are glycerol and NADP+; the products are D-glyceraldehyde and NADPH. The reaction is reversible.
How is glycerol dehydrogenase (NADP+) regulated?
It can be induced by D-galacturonate in Aspergillus nidulans and is essential for osmotolerance. Divalent cations may affect activity in Klebsiella pneumoniae.
What research methods are used to study glycerol dehydrogenase (NADP+) activity?
Common methods include enzyme activity assays, RT-qPCR, heterologous expression, gene knockout, and site-directed mutagenesis.
Conclusion
Glycerol dehydrogenase (NADP+) activity (GO:0047956) is a key molecular function that links glycerol metabolism to redox balance and stress adaptation across fungi, bacteria, and mammals. Its role in osmotolerance and biotechnological production of chiral compounds underscores its importance in both fundamental and applied research. By leveraging CRISPR-based models and biochemical assays, researchers can further unravel its regulatory mechanisms and physiological roles. EDITGENE provides the tools and expertise to accelerate these discoveries.
References
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- 2. Richter N et al.. 2009. Characterisation of a recombinant NADP-dependent glycerol dehydrogenase from Gluconobacter oxydans and its application in the production of L-glyceraldehyde.. Chembiochem 10(11):1888-96 PMID: 19579248
- 3. de Vries RP et al.. 2003. Glycerol dehydrogenase, encoded by gldB is essential for osmotolerance in Aspergillus nidulans.. Mol Microbiol 49(1):131-41 PMID: 12823816
- 4. Camacho Morales RL et al.. 2010. Analysis of glycerol dehydrogenase activities present in Mucor circinelloides YR-1.. Antonie Van Leeuwenhoek 98(4):437-45 PMID: 20512634
- 5. Luo LH et al.. 2011. Stimulation of reductive glycerol metabolism by overexpression of an aldehyde dehydrogenase in a recombinant Klebsiella pneumoniae strain defective in the oxidative pathway.. J Ind Microbiol Biotechnol 38(8):991-9 PMID: 20862513
- 6. Hondmann DH et al.. 1991. Glycerol catabolism in Aspergillus nidulans.. J Gen Microbiol 137(3):629-36 PMID: 2033381
- 7. Johnson EA et al.. 1985. Inactivation of glycerol dehydrogenase of Klebsiella pneumoniae and the role of divalent cations.. J Bacteriol 164(1):479-83 PMID: 3900046
- 8. Kormann AW et al.. 1972. Purification and properties of an NADP + -dependent glycerol dehydrogenase from rabbit skeletal muscle.. Biochim Biophys Acta 258(1):40-55 PMID: 4400494
