GO:0047933 glucose-1,6-bisphosphate synthase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0047933 describes glucose-1,6-bisphosphate synthase activity, the enzyme activity that transfers a phosphate group from 3-phospho-D-glyceroyl phosphate to alpha-D-glucose 1-phosphate, producing 3-phospho-D-glycerate and alpha-D-glucose 1,6-bisphosphate plus a proton.
• In mammals, this activity is carried out by a member of the alpha-D-phosphohexomutase family, identified as glucose-1,6-bisphosphate synthase, which is distinct from the classical phosphoglucomutase.
• The enzyme is widely distributed in tissues such as skeletal muscle, where it contributes to the synthesis of glucose 1,6-bisphosphate, a potent regulator of carbohydrate metabolism.
• Glucose 1,6-bisphosphate levels change rapidly in human skeletal muscle during isometric contraction, indicating a dynamic role in energy metabolism.
• The synthase activity can be modulated by vanadate and other effectors, linking it to redox and phosphate metabolism.
• Studying GO:0047933 helps researchers understand metabolic regulation in red blood cells, muscle, and other tissues, with implications for disorders of glycolysis and energy homeostasis.
Description
Glucose-1,6-bisphosphate synthase activity (GO:0047933) is a molecular function that catalyzes the transfer of a phosphate group from 3-phospho-D-glyceroyl phosphate to alpha-D-glucose 1-phosphate, yielding 3-phospho-D-glycerate and alpha-D-glucose 1,6-bisphosphate. This reaction is central to the synthesis of glucose 1,6-bisphosphate, a metabolite that regulates key enzymes of carbohydrate metabolism, including phosphoglucomutase and phosphofructokinase. The activity is found in a variety of organisms and tissues, with early biochemical studies characterizing it in pig skeletal muscle and other tissues. In mammals, the enzyme responsible was molecularly identified as a member of the alpha-D-phosphohexomutase family, distinct from phosphoglucomutase, and named glucose-1,6-bisphosphate synthase. This discovery clarified that glucose 1,6-bisphosphate can be synthesized independently of the glycolytic intermediate glucose 1,6-bisphosphate derived from phosphoglucomutase. The synthase activity is important for maintaining cellular levels of glucose 1,6-bisphosphate, which acts as a cofactor for phosphoglucomutase and influences glycolytic flux. In human skeletal muscle, glucose 1,6-bisphosphate increases transiently during isometric contraction, suggesting a role in rapid metabolic adaptation. In red blood cells, manipulation of glucose 1,6-bisphosphate levels has been used to probe its metabolic role, highlighting the importance of the synthase in erythrocyte function. The activity is also developmentally regulated, as shown by changes during reticulocyte maturation. Understanding GO:0047933 therefore provides insight into how cells regulate glucose 1,6-bisphosphate and, consequently, energy metabolism.
glucose-1,6-bisphosphate synthase activity At A Glance
| GO ID | GO:0047933 |
|---|---|
| GO term | glucose-1,6-bisphosphate synthase activity |
| Ontology | molecular_function |
| Synonym | 3-phospho-D-glyceroyl-phosphate:alpha-D-glucose-1-phosphate 6-phosphotransferase activity; glucose-1,6-bisphosphate synthetase activity; glucose 1,6-diphosphate synthase activity |
| Major function | Catalyzes the synthesis of alpha-D-glucose 1,6-bisphosphate from alpha-D-glucose 1-phosphate and 3-phospho-D-glyceroyl phosphate |
| Reaction | 3-phospho-D-glyceroyl phosphate + alpha-D-glucose 1-phosphate = 3-phospho-D-glycerate + alpha-D-glucose 1,6-bisphosphate + H+ |
| Enzyme family | alpha-D-phosphohexomutase family (in mammals) |
| Tissue distribution | Skeletal muscle, red blood cells, and other tissues |
What Is GO:0047933?
Glucose-1,6-bisphosphate synthase activity is defined as the catalysis of the reaction: 3-phospho-D-glyceroyl phosphate + alpha-D-glucose 1-phosphate = 3-phospho-D-glycerate + alpha-D-glucose 1,6-bisphosphate + H+. In other words, it is an enzyme activity that transfers a phosphate group from 3-phospho-D-glyceroyl phosphate to alpha-D-glucose 1-phosphate, producing glucose 1,6-bisphosphate and 3-phospho-D-glycerate. This activity is synonymous with 3-phospho-D-glyceroyl-phosphate:alpha-D-glucose-1-phosphate 6-phosphotransferase, glucose-1,6-bisphosphate synthetase, and glucose 1,6-diphosphate synthase. It belongs to the molecular function ontology and is distinct from phosphoglucomutase, although both can generate glucose 1,6-bisphosphate.
Why Is glucose-1,6-bisphosphate synthase activity Important in Cell Biology?
Glucose-1,6-bisphosphate synthase activity is important because it produces glucose 1,6-bisphosphate, a metabolite that regulates key enzymes of glycolysis and gluconeogenesis, thereby influencing cellular energy balance. The activity is dynamically regulated in response to metabolic demands, as shown by its transient increase in human skeletal muscle during isometric contraction. In red blood cells, glucose 1,6-bisphosphate levels affect glycolytic rate and oxygen transport, and the synthase contributes to maintaining these levels. The enzyme is also developmentally regulated, with changes observed during reticulocyte maturation. Moreover, the synthase can be modulated by vanadate, linking it to phosphate and redox metabolism. Understanding this activity is therefore relevant to metabolic physiology and to diseases involving disturbed carbohydrate metabolism.
• Provides an alternative route for glucose 1,6-bisphosphate synthesis, independent of phosphoglucomutase.
• Regulates glycolytic flux by controlling levels of glucose 1,6-bisphosphate, a cofactor for phosphoglucomutase.
• Shows rapid changes in activity during muscle contraction, linking it to energy demand.
• Plays a role in red blood cell metabolism, where glucose 1,6-bisphosphate influences glycolysis and oxygen affinity.
• Is developmentally regulated during reticulocyte maturation, suggesting a role in erythroid differentiation.
• Can be modulated by vanadate, indicating sensitivity to cellular redox and phosphate status.
• Is conserved across tissues such as pig skeletal muscle and rabbit skeletal muscle.
• Its molecular identification as a distinct alpha-D-phosphohexomutase family member enables targeted studies.
• Dysregulation may contribute to metabolic disorders, though direct disease links remain to be fully established.
Molecular Mechanism of glucose-1,6-bisphosphate synthase activity
Substrate recognition and binding
In simple terms: The enzyme grabs its two starting materials, 3-phospho-D-glyceroyl phosphate and alpha-D-glucose 1-phosphate, and holds them in place.
Glucose-1,6-bisphosphate synthase specifically binds 3-phospho-D-glyceroyl phosphate and alpha-D-glucose 1-phosphate. Early studies on pig skeletal muscle synthase showed specificity for these substrates, distinguishing it from other phosphotransferases. The enzyme belongs to the alpha-D-phosphohexomutase family, which typically uses a phosphoserine intermediate, but the synthase catalyzes a direct transfer of phosphate from 3-phospho-D-glyceroyl phosphate to glucose 1-phosphate.
Catalytic transfer of phosphate
In simple terms: The enzyme moves a phosphate group from one molecule to the other, creating glucose 1,6-bisphosphate.
The catalytic mechanism involves the transfer of a phosphate group from 3-phospho-D-glyceroyl phosphate to the C6 hydroxyl of alpha-D-glucose 1-phosphate, yielding 3-phospho-D-glycerate and alpha-D-glucose 1,6-bisphosphate, with release of a proton. This reaction is distinct from the phosphoglucomutase reaction, which interconverts glucose 1-phosphate and glucose 6-phosphate via glucose 1,6-bisphosphate as a cofactor. The synthase activity can be measured by monitoring the formation of glucose 1,6-bisphosphate or 3-phospho-D-glycerate.
Cofactors and effectors
In simple terms: Some chemicals can speed up or slow down the enzyme, such as vanadate.
The synthase activity is influenced by vanadate, which affects both glucose-1,6-bisphosphate synthase and glucose-1,6-bisphosphatase activities of phosphoglucomutase. This suggests that the enzyme is sensitive to the cellular redox and phosphate environment. Other effectors may include metabolites that modulate the alpha-D-phosphohexomutase family, but specific cofactors for the synthase remain to be fully defined.
Tissue-specific regulation and physiological context
In simple terms: The enzyme works differently in different tissues and changes with activity.
The synthase activity is present in various tissues, with early studies characterizing it in pig skeletal muscle, rabbit skeletal muscle, and red blood cells. In human skeletal muscle, glucose 1,6-bisphosphate levels increase transiently during isometric contraction, indicating that the synthase or related activities are dynamically regulated during exercise. During reticulocyte maturation, glucose 1,6-bisphosphate levels change, suggesting developmental regulation of the synthase. These findings highlight that the activity is not constitutive but responds to physiological demands.
Key Genes Involved in GO:0047933 glucose-1,6-bisphosphate synthase activity
The genes and proteins associated with glucose-1,6-bisphosphate synthase activity include the enzyme itself and related metabolic regulators.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PGM2 | Encodes a member of the alpha-D-phosphohexomutase family with glucose-1,6-bisphosphate synthase activity | Key enzyme for glucose 1,6-bisphosphate synthesis; target for metabolic studies |
| PGM1 | Phosphoglucomutase 1, which also produces glucose 1,6-bisphosphate as a cofactor | Comparison with synthase to distinguish pathways |
| PGM3 | Phosphoglucomutase 3, involved in hexosamine metabolism | Family member for evolutionary and functional studies |
| PGM5 | Phosphoglucomutase 5, predominantly in muscle | Tissue-specific family member |
| GYS1 | Glycogen synthase 1, downstream consumer of glucose 1-phosphate | Links synthase activity to glycogen metabolism |
| PYGM | Muscle glycogen phosphorylase, produces glucose 1-phosphate | Provides substrate for synthase in muscle |
| PFKM | Phosphofructokinase, muscle type, regulated by glucose 1,6-bisphosphate | Effector target of glucose 1,6-bisphosphate |
| ALDOA | Aldolase A, glycolytic enzyme | Glycolytic context |
| GAPDH | Glyceraldehyde-3-phosphate dehydrogenase, produces 3-phospho-D-glyceroyl phosphate | Provides substrate for synthase |
| PGK1 | Phosphoglycerate kinase 1, generates 3-phospho-D-glyceroyl phosphate | Substrate supply |
| PKM | Pyruvate kinase, muscle, glycolytic enzyme | Glycolytic flux |
| LDHA | Lactate dehydrogenase A, anaerobic glycolysis | Metabolic context |
| SLC2A4 | GLUT4 glucose transporter, muscle glucose uptake | Links to glucose availability |
| INSR | Insulin receptor, regulates glucose metabolism | Upstream signaling |
| AKT1 | Protein kinase B, promotes glycolysis | Signaling regulator |
| HIF1A | Hypoxia-inducible factor 1 alpha, regulates glycolytic genes | Hypoxic response |
| TPI1 | Triosephosphate isomerase, glycolytic enzyme | Glycolytic pathway |
| ENO1 | Enolase 1, glycolytic enzyme | Glycolytic pathway |
How Is glucose-1,6-bisphosphate synthase activity Regulated?
The activity of glucose-1,6-bisphosphate synthase is regulated at multiple levels. In skeletal muscle, glucose 1,6-bisphosphate levels increase transiently during isometric contraction, suggesting that the synthase is activated by contraction-induced signals. The enzyme can be inhibited by vanadate, which also affects phosphoglucomutase-associated activities, indicating regulation by phosphate analogs and redox state. Tissue-specific expression of the enzyme, as seen in pig and rabbit skeletal muscle, suggests developmental or hormonal control. During reticulocyte maturation, glucose 1,6-bisphosphate levels decline, implying downregulation of the synthase or related activities. However, specific transcriptional or post-translational regulators of the synthase gene remain to be fully elucidated.
glucose-1,6-bisphosphate synthase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PGM2 | Metabolic regulation; glucose 1,6-bisphosphate synthesis | Knockout cell lines, metabolic flux analysis |
| PGM1 | Glycogen storage disease, glycolysis | Point mutation knock-in, patient-derived cells |
| PFKM | Glycogen storage disease type VII, glycolysis | Overexpression, enzyme activity assays |
| GYS1 | Glycogen metabolism disorders | Knockout, glycogen measurement |
| LDHA | Cancer metabolism, anaerobic glycolysis | Knockout, proliferation assays |
Metabolic disorders and glycolysis
Glucose-1,6-bisphosphate synthase activity contributes to glucose 1,6-bisphosphate levels, which regulate glycolytic enzymes such as phosphofructokinase. Dysregulation of this activity could therefore impact metabolic disorders characterized by altered glycolysis, although direct disease associations are not yet firmly established.
Red blood cell disorders
In red blood cells, glucose 1,6-bisphosphate modulates glycolytic rate and oxygen affinity. Overloading erythrocytes with glucose 1,6-bisphosphate has been used to investigate its metabolic role, suggesting that the synthase activity is relevant to red blood cell function and potentially to hemolytic disorders.
Muscle physiology and exercise
The transient increase in glucose 1,6-bisphosphate during isometric contraction in human skeletal muscle indicates a role for the synthase in exercise metabolism. Alterations in this pathway might affect muscle performance, but specific disease links require further study.
From glucose-1,6-bisphosphate synthase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of glucose-1,6-bisphosphate synthase affect glycolytic flux? | CRISPR knockout of PGM2 in muscle or red blood cell lines |
| How do point mutations in the active site alter synthase activity? | CRISPR point mutation knock-in of catalytic residues |
| Can tagged synthase be used to study localization? | Knock-in of fluorescent or affinity tags |
| Does overexpression of synthase increase glucose 1,6-bisphosphate levels? | CRISPR overexpression or cDNA transduction |
| What is the role of synthase in muscle contraction? | Inducible knockout in skeletal muscle cells |
| How does synthase interact with other metabolic enzymes? | Knock-in of proximity labeling tags (e.g., BioID) |
How to Study the glucose-1,6-bisphosphate synthase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme-coupled assay | Synthase activity via NADH oxidation | Kinetic characterization |
| LC-MS metabolomics | Glucose 1,6-bisphosphate levels | Metabolic profiling |
| CRISPR knockout | Loss-of-function phenotype | Causal gene studies |
| CRISPR knock-in | Tagged or mutant enzyme expression | Localization and interaction studies |
| RNA-seq | Transcriptional changes | Pathway analysis |
| Western blot | Protein expression levels | Validation of knockouts |
| Seahorse assay | Glycolytic rate | Functional metabolic assessment |
Enzyme activity assays
Glucose-1,6-bisphosphate synthase activity can be measured by monitoring the formation of glucose 1,6-bisphosphate or 3-phospho-D-glycerate using coupled enzymatic assays or chromatographic methods. These assays are essential for characterizing the kinetic properties and substrate specificity of the enzyme.
Metabolite profiling
Mass spectrometry-based metabolomics can quantify glucose 1,6-bisphosphate and related metabolites in cells and tissues, allowing researchers to assess the impact of genetic perturbations on the synthase pathway. This approach is particularly useful for studying dynamic changes during contraction or maturation.
Genetic manipulation and phenotyping
CRISPR-Cas9 knockout, knock-in, and overexpression models enable causal testing of the synthase gene in metabolic pathways. Phenotypic readouts include glycolytic flux, ATP levels, and glycogen content.
Protein interaction studies
Co-immunoprecipitation, proximity labeling, and yeast two-hybrid can identify interacting partners of the synthase, helping to place it in the metabolic network.
How CRISPR Can Be Used to Study GO:0047933 glucose-1,6-bisphosphate synthase activity
Knockout
CRISPR knockout of the gene encoding glucose-1,6-bisphosphate synthase (e.g., PGM2) can eliminate the activity, allowing researchers to determine its contribution to glucose 1,6-bisphosphate synthesis and downstream metabolism. Knockout cell lines are valuable for metabolic flux analysis and for testing compensatory pathways.
Point Mutation
Introducing point mutations in catalytic residues of the synthase can dissect the mechanism of phosphate transfer and distinguish it from other family members. Such models are useful for structure-function studies and for validating substrate specificity.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the endogenous locus enables real-time tracking of synthase expression and localization without overexpression artifacts. This approach can reveal tissue-specific and developmental regulation.
Overexpression
Overexpression of the synthase gene can increase glucose 1,6-bisphosphate levels, providing a gain-of-function model to study its effects on glycolysis and cellular physiology. This is particularly useful in red blood cells and muscle cells where the metabolite has known regulatory roles.
How EDITGENE Supports glucose-1,6-bisphosphate synthase activity Research
Researchers studying glucose-1,6-bisphosphate synthase activity-related genes often need to determine whether a candidate gene is causally involved in metabolite regulation, metabolic flux, or disease phenotypes. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for glucose-1,6-bisphosphate synthase activity research.
Frequently Asked Questions About glucose-1,6-bisphosphate synthase activity
What is glucose-1,6-bisphosphate synthase activity?
It is an enzyme activity that catalyzes the transfer of a phosphate group from 3-phospho-D-glyceroyl phosphate to alpha-D-glucose 1-phosphate, producing 3-phospho-D-glycerate and alpha-D-glucose 1,6-bisphosphate.
What is the GO ID for glucose-1,6-bisphosphate synthase activity?
The GO ID is GO:0047933.
What genes are involved in glucose-1,6-bisphosphate synthase activity?
In mammals, the enzyme is encoded by a member of the alpha-D-phosphohexomutase family, identified as PGM2 (glucose-1,6-bisphosphate synthase). Other family members include PGM1, PGM3, and PGM5.
What reaction does glucose-1,6-bisphosphate synthase catalyze?
It catalyzes: 3-phospho-D-glyceroyl phosphate + alpha-D-glucose 1-phosphate = 3-phospho-D-glycerate + alpha-D-glucose 1,6-bisphosphate + H+.
How is glucose-1,6-bisphosphate synthase regulated?
It is regulated by metabolic demand, as shown by transient increases in glucose 1,6-bisphosphate during muscle contraction, and can be inhibited by vanadate.
What tissues express glucose-1,6-bisphosphate synthase?
It is present in skeletal muscle, red blood cells, and other tissues, with early studies in pig and rabbit skeletal muscle.
Why is glucose-1,6-bisphosphate synthase important for metabolism?
It produces glucose 1,6-bisphosphate, which regulates glycolytic enzymes such as phosphofructokinase and phosphoglucomutase, thereby influencing energy metabolism.
Can CRISPR be used to study glucose-1,6-bisphosphate synthase?
Yes, CRISPR knockout, knock-in, and overexpression models can be used to dissect its function and metabolic impact.
What diseases are linked to glucose-1,6-bisphosphate synthase?
Direct disease links are not fully established, but the pathway is relevant to metabolic disorders, red blood cell function, and muscle physiology.
How can I measure glucose-1,6-bisphosphate synthase activity?
Activity can be measured using enzyme-coupled assays that monitor glucose 1,6-bisphosphate formation or 3-phospho-D-glycerate production.
Conclusion
Glucose-1,6-bisphosphate synthase activity (GO:0047933) is a key molecular function for the synthesis of glucose 1,6-bisphosphate, a metabolite that regulates carbohydrate metabolism. Its identification as a distinct alpha-D-phosphohexomutase family member has clarified how cells generate this important bisphosphate independently of phosphoglucomutase. The activity is dynamically regulated in muscle and red blood cells, and its study offers insights into metabolic physiology and potential disease mechanisms. Continued research using CRISPR models and metabolic profiling will further define its roles and therapeutic relevance.
References
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- 2. Maliekal P et al.. 2007. Molecular identification of mammalian phosphopentomutase and glucose-1,6-bisphosphate synthase, two members of the alpha-D-phosphohexomutase family.. J Biol Chem 282(44):31844-51 PMID: 17804405
- 3. Lee AD et al.. 1989. Transient increase in glucose 1,6-bisphosphate in human skeletal muscle during isometric contraction.. Biochem J 258(3):915-8 PMID: 2730576
- 4. Piatti E et al.. 1992. Glucose 1,6-bisphosphate-overloaded erythrocytes: a strategy to investigate the metabolic role of the bisphosphate in red blood cells.. Arch Biochem Biophys 293(1):117-21 PMID: 1309980
- 5. Piatti E et al.. 1991. Specificity of glucose 1,6-bisphosphate synthesis in rabbit skeletal muscle.. Comp Biochem Physiol B 100(1):67-71 PMID: 1661660
- 6. Gallego C et al.. 1990. 2,3-Bisphosphoglycerate, fructose, 2,6-bisphosphate and glucose 1,6-bisphosphate during maturation of reticulocytes with low 2,3-bisphosphoglycerate content.. Mol Cell Biochem 99(1):21-4 PMID: 2177836
- 7. Carreras M et al.. 1988. Metabolism of glucose 1,6-P2--III. Partial purification and characterization of glucose 1,6-P2 synthase from pig skeletal muscle.. Comp Biochem Physiol B 90(4):739-44 PMID: 2854765
- 8. Climent F et al.. 1985. Metabolism of glucose 1,6-P2. I. Enzymes involved in the synthesis of glucose 1,6-P2 in pig tissues.. Comp Biochem Physiol B 81(3):737-42 PMID: 2992877
