GO:0030393 fructoselysine metabolic process: Amadori Compound Catabolism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0030393 fructoselysine metabolic process describes the chemical reactions and pathways involving fructoselysine, a fructose-lysine Amadori product formed by non-enzymatic glycation of proteins.
• Fructoselysine is a key advanced glycation end-product (AGE) precursor and is used as a biomarker of fasting and postprandial hyperglycemia in diabetes.
• The pathway is best characterized in bacteria such as Escherichia coli, where fructoselysine 3-epimerase and fructoselysine kinase initiate its degradation.
• Gut bacteria including Intestinimonas butyriciproducens degrade fructoselysine and contribute to host metabolic health.
• Interindividual differences in microbial fructoselysine degradation capacity exist in human fecal slurries, suggesting personalized metabolic responses.
• CRISPR knockout, knock-in, and overexpression models are essential to dissect the enzymatic steps and physiological roles of fructoselysine metabolism.
Description
Fructoselysine is a fructose molecule containing a lysine group in place of a hydroxyl group, and it is formed when glucose reacts non-enzymatically with the epsilon-amino group of lysine residues in proteins, generating an Amadori product. The Gene Ontology term GO:0030393, fructoselysine metabolic process, encompasses the chemical reactions and pathways that involve this compound, including its synthesis, modification, and degradation. This process is of growing interest because fructoselysine and related glycated protein degradation products are indicators of fasting and postprandial hyperglycemia in diabetes, linking protein glycation to metabolic dysfunction. In bacteria, fructoselysine metabolism provides a source of carbon and nitrogen and involves specialized enzymes such as fructoselysine 3-epimerase, which acts on the unusual Amadori compound psicoselysine in Escherichia coli. Enzymatic repair of Amadori products, including fructoselysine, is a conserved strategy to mitigate glycation damage. In the human gut, microbial fructoselysine degradation shows substantial interindividual differences, and gut bacteria such as Intestinimonas butyriciproducens can improve host metabolic health, partly through metabolism of glycated compounds. Understanding fructoselysine metabolic process is therefore relevant to diabetes research, gut microbiome science, and the development of biomarkers for glycemic control. This article synthesizes authoritative QuickGO data and verified PubMed literature to provide a research-grade overview of the pathway, its genes, disease links, and experimental models.
fructoselysine metabolic process At A Glance
| GO ID | GO:0030393 |
|---|---|
| GO term | fructoselysine metabolic process |
| Ontology | biological_process |
| Synonym | fructoselysine metabolism |
| Definition | The chemical reactions and pathways involving fructoselysine, a fructose molecule containing a lysine group in place of a hydroxyl group. |
| Major function | Metabolism of the Amadori product fructoselysine, including its degradation and repair. |
| Related compounds | Psicoselysine, glucoselysine, advanced glycation end-products (AGEs). |
| Key organisms | Escherichia coli, gut bacteria such as Intestinimonas butyriciproducens, and humans. |
| Disease relevance | Diabetes, diabetic retinopathy, vascular complications. |
What Is GO:0030393?
GO:0030393 fructoselysine metabolic process is defined as the chemical reactions and pathways involving fructoselysine, a fructose molecule containing a lysine group in place of a hydroxyl group. This biological process includes enzymatic steps that modify, degrade, or synthesize fructoselysine, an Amadori product formed by glycation of protein lysine residues.
Why Is fructoselysine metabolic process Important in Cell Biology?
Fructoselysine metabolic process is important because fructoselysine is a major Amadori product and a precursor to advanced glycation end-products, which accumulate in diabetes and contribute to vascular complications. Measuring glycated and oxidized protein degradation products, including fructoselysine, helps assess glycemic control and disease risk. Moreover, gut microbial degradation of fructoselysine influences host metabolic health, and interindividual differences in this capacity may affect personalized responses to diet and diabetes.
• Fructoselysine is a biomarker of fasting and postprandial hyperglycemia in diabetes.
• It is a precursor to advanced glycation end-products (AGEs) linked to vascular complications.
• Microbial fructoselysine degradation contributes to host metabolic health.
• Interindividual differences in fructoselysine degradation exist in human gut microbiota.
• Enzymatic repair of Amadori products like fructoselysine mitigates glycation damage.
• Fructoselysine 3-epimerase is a key enzyme in bacterial fructoselysine metabolism.
• Sex differences influence the development of experimental diabetic retinopathy, a complication linked to glycation.
• Menaquinone-7 supplementation alters AGE levels in diabetic rats, highlighting modifiable pathways.
• Glucoselysine, a related Amadori product, is associated with vascular complications in type 2 diabetes.
• CRISPR models enable causal testing of genes in fructoselysine metabolism.
What Happens During fructoselysine metabolic process?
Formation of fructoselysine via glycation
In simple terms: Fructoselysine forms when sugar sticks to proteins without help from enzymes.
Fructoselysine is generated when glucose reacts non-enzymatically with the epsilon-amino group of lysine residues in proteins, forming an Amadori product. This glycation reaction is a key step in the formation of advanced glycation end-products and is accelerated under hyperglycemic conditions.
Enzymatic degradation by fructoselysine 3-epimerase and kinases
In simple terms: Bacteria use special enzymes to break down fructoselysine.
In Escherichia coli, fructoselysine 3-epimerase catalyzes the epimerization of psicoselysine, an unusual Amadori compound related to fructoselysine, as part of its metabolism. Enzymatic repair of Amadori products, including fructoselysine, involves dedicated enzymes that reverse or degrade glycated amino acids.
Microbial fructoselysine degradation in the gut
In simple terms: Gut bacteria digest fructoselysine, and different people have different abilities to do this.
Human fecal slurries show substantial interindividual differences in microbial fructoselysine degradation capacities, indicating personalized metabolic functions. The gut bacterium Intestinimonas butyriciproducens improves host metabolic health, and its metabolism of glycated compounds such as fructoselysine may contribute to these benefits.
Repair and detoxification of Amadori products
In simple terms: Cells have repair systems to remove damaged sugar-protein adducts.
Enzymatic repair of Amadori products is a conserved mechanism to mitigate glycation damage, and fructoselysine is a substrate for such repair pathways. This repair capacity is relevant to diabetes, where glycation products accumulate and contribute to complications.
Key Genes Involved in GO:0030393 fructoselysine metabolic process
The following genes and proteins are experimentally implicated in fructoselysine metabolic process or related Amadori product metabolism, based on verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| frlA | Fructoselysine 3-epimerase in E. coli | Catalyzes epimerization of psicoselysine, a fructoselysine-related Amadori compound |
| frlB | Fructoselysine kinase in E. coli | Phosphorylates fructoselysine as part of its degradation pathway |
| frlC | Fructoselysine-6-phosphate deglycase | Releases lysine and glucose-6-phosphate from fructoselysine-6-phosphate |
| frlD | Fructoselysine transporter | Uptake of fructoselysine in bacteria |
| Intestinimonas butyriciproducens genes | Microbial fructoselysine degradation | Improves host metabolic health in cohort and animal studies |
| Human gut microbiota enzymes | Fructoselysine degradation | Interindividual differences in metabolic capacities |
| Glucoselysine-related enzymes | Polyol pathway AGE formation | Associated with vascular complications in type 2 diabetes |
| AGE receptor (AGER/RAGE) | Recognition of advanced glycation end-products | Mediates downstream effects of glycation |
| Glyoxalase system | Detoxification of glycation precursors | Protects against AGE formation |
| Fructosamine-3-kinase (FN3K) | Repair of Amadori products | Phosphorylates fructoselysine and related compounds |
| FN3K-RP | Fructosamine-3-kinase related protein | Potential role in Amadori product repair |
| Menaquinone-7 target genes | Modulation of AGE levels | Supplementation alters AGE markers in diabetic rats |
| Sex-specific genes in diabetic retinopathy | Retinal vascular complications | Sex differences in experimental diabetic retinopathy |
| Fasting hyperglycemia markers | Glycated protein degradation products | Indicators of glycemic control |
| Postprandial hyperglycemia markers | Glycated protein degradation products | Indicators of glycemic control |
| Psicoselysine metabolic enzymes | Unusual Amadori compound metabolism | Studied in E. coli |
| Gut microbial butyrate producers | Host metabolic health | Intestinimonas butyriciproducens intervention studies |
| Fecal slurry enzymes | Microbial fructoselysine degradation | In vitro model for interindividual differences |
How Is fructoselysine metabolic process Regulated?
Fructoselysine metabolic process is regulated at multiple levels. In bacteria, expression of fructoselysine degradation genes is likely induced by the presence of fructoselysine or related Amadori compounds, though specific regulators are not fully defined in the verified literature. In the gut, microbial fructoselysine degradation capacity varies between individuals, suggesting host diet and microbiome composition influence pathway activity. In humans, hyperglycemia increases glycation and fructoselysine formation, while enzymatic repair systems such as fructosamine-3-kinase modulate Amadori product levels. Menaquinone-7 supplementation has been shown to alter multiple advanced glycation end-products in diabetic rats, indicating that nutritional factors can regulate glycation pathways.
fructoselysine metabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FN3K | Diabetes, glycation repair | Knockout mice, cell lines |
| AGER/RAGE | Vascular complications | Knockout mice, endothelial cells |
| Intestinimonas butyriciproducens genes | Metabolic health | Gnotobiotic mice, fecal slurry assays |
| Glucoselysine-related enzymes | Type 2 diabetes vascular complications | Cell models, patient samples |
| Sex-specific genes | Diabetic retinopathy | Sex-stratified animal models |
Diabetes and glycemic control
Fructoselysine and related glycated protein degradation products are indicators of fasting and postprandial hyperglycemia in diabetes, making them useful biomarkers for glycemic control. Elevated fructoselysine reflects increased protein glycation under hyperglycemic conditions.
Diabetic vascular complications
Advanced glycation end-products, including those derived from fructoselysine, contribute to vascular complications in type 2 diabetes. Glucoselysine, a related Amadori product of the polyol pathway, is associated with vascular complications, highlighting the clinical relevance of Amadori product metabolism.
Diabetic retinopathy and sex differences
Experimental diabetic retinopathy develops with sex differences, and glycation pathways may contribute to this complication. Understanding fructoselysine metabolism could inform sex-specific therapeutic approaches.
Gut microbiome and metabolic health
Gut bacteria such as Intestinimonas butyriciproducens improve host metabolic health, and their ability to degrade fructoselysine may mediate some benefits. Interindividual differences in microbial fructoselysine degradation could affect personalized metabolic responses.
From fructoselysine metabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate fructoselysine degradation? | CRISPR knockout cell lines |
| Does a point mutation in frlA alter enzyme activity? | Point-mutation knock-in cells |
| Can we tag endogenous fructoselysine enzymes? | Tagged knock-in (e.g., GFP) |
| Does overexpression of FN3K reduce glycation? | Overexpression cell models |
| Which gut microbial genes degrade fructoselysine? | CRISPR library screening in bacteria |
| What is the metabolic impact of fructoselysine? | Metabolomics and flux analysis |
How to Study the fructoselysine metabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS metabolomics | Fructoselysine and AGE levels | Biomarker discovery in diabetes |
| Fecal slurry assay | Microbial degradation capacity | Interindividual differences |
| Enzyme kinetics | Fructoselysine 3-epimerase activity | Mechanistic studies |
| CRISPR knockout screening | Gene essentiality for fructoselysine metabolism | Functional genomics |
| RNA-seq | Expression of fructoselysine-related genes | Pathway regulation |
| Proteomics | Glycated protein profiles | AGE research |
| Animal intervention studies | Host metabolic health | Intestinimonas butyriciproducens effects |
| Sex-stratified analysis | Diabetic retinopathy development | Sex differences |
Metabolomics and glycation profiling
Mass spectrometry-based metabolomics can quantify fructoselysine and related Amadori products in biological samples, as demonstrated in studies of glycated protein degradation products in diabetes. These methods are essential for assessing pathway activity and biomarker potential.
Microbial degradation assays
In vitro fecal slurry models measure microbial fructoselysine degradation capacities and reveal interindividual differences. Such assays can be combined with metagenomics to identify responsible genes.
Enzyme activity assays
Recombinant fructoselysine 3-epimerase and kinases can be assayed for activity using substrates like psicoselysine, as shown in E. coli studies. These assays define kinetic parameters and substrate specificity.
CRISPR screening and functional genomics
CRISPR knockout libraries can identify genes required for fructoselysine metabolism in bacteria and mammalian cells. This approach links genotype to metabolic phenotype and is supported by the need to dissect enzymatic steps.
How CRISPR Can Be Used to Study GO:0030393 fructoselysine metabolic process
Knockout
CRISPR knockout of candidate genes such as frlA, frlB, or FN3K can test their requirement for fructoselysine degradation and repair. Knockout cell lines or bacteria lacking these genes will accumulate fructoselysine or show impaired growth on fructoselysine as a carbon source.
Point Mutation
Point mutations in catalytic residues of fructoselysine 3-epimerase or fructoselysine kinase can dissect enzyme mechanism. CRISPR-mediated point mutation introduces specific amino acid changes to test activity and substrate specificity.
Knock-in
Knock-in of tagged versions of fructoselysine enzymes (e.g., GFP or FLAG) enables localization and interaction studies. This approach helps track enzyme expression and complex formation in live cells.
Overexpression
Overexpression of fructoselysine repair enzymes such as FN3K can reduce glycation damage and protect against AGE accumulation. CRISPR activation or cDNA overexpression models are useful to test therapeutic potential.
How EDITGENE Supports fructoselysine metabolic process Research
Researchers studying fructoselysine metabolic process-related genes often need to determine whether a candidate gene is causally involved in fructoselysine degradation, repair, or host metabolic health. EDITGENE provides comprehensive CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for fructoselysine metabolic process research.
Frequently Asked Questions About fructoselysine metabolic process
What is fructoselysine metabolic process?
Fructoselysine metabolic process (GO:0030393) is the set of chemical reactions and pathways involving fructoselysine, a fructose-lysine Amadori product formed by glycation.
What genes are involved in fructoselysine metabolic process?
Key genes include frlA, frlB, frlC, frlD in E. coli, and FN3K in humans, as well as gut microbial genes from Intestinimonas butyriciproducens.
How is fructoselysine formed?
Fructoselysine forms when glucose reacts non-enzymatically with lysine residues in proteins, generating an Amadori product.
Why is fructoselysine important in diabetes?
Fructoselysine and related glycated protein degradation products are indicators of fasting and postprandial hyperglycemia in diabetes.
Can gut bacteria degrade fructoselysine?
Yes, gut bacteria such as Intestinimonas butyriciproducens can degrade fructoselysine, and human fecal slurries show interindividual differences in this capacity.
What enzymes degrade fructoselysine?
Fructoselysine 3-epimerase and fructoselysine kinase are key enzymes in bacterial fructoselysine degradation.
Is fructoselysine related to advanced glycation end-products?
Yes, fructoselysine is a precursor to advanced glycation end-products, which are linked to vascular complications in diabetes.
How can I study fructoselysine metabolism with CRISPR?
CRISPR knockout, point mutation, knock-in, and overexpression models can test gene function in fructoselysine metabolism.
What are the research methods for fructoselysine metabolic process?
Methods include LC-MS metabolomics, fecal slurry assays, enzyme kinetics, and CRISPR screening.
Does fructoselysine metabolism differ between sexes?
Sex differences have been observed in experimental diabetic retinopathy, a complication linked to glycation, suggesting potential sex-specific effects.
Conclusion
GO:0030393 fructoselysine metabolic process encompasses the formation, degradation, and repair of fructoselysine, an Amadori product with significant implications for diabetes and metabolic health. Bacterial enzymes such as fructoselysine 3-epimerase and gut microbial degradation pathways are key players, and interindividual differences in microbial capacity highlight personalized aspects. CRISPR-based models are powerful tools to dissect these pathways and identify therapeutic targets. EDITGENE offers comprehensive CRISPR services to support research on fructoselysine metabolism and related diseases.
References
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- 2. Chen Y et al.. 2024. Sex differences in the development of experimental diabetic retinopathy.. Sci Rep 14(1):22812 PMID: 39354039
- 3. Rampanelli E et al.. 2025. Gut bacterium Intestinimonas butyriciproducens improves host metabolic health: evidence from cohort and animal intervention studies.. Microbiome 13(1):15 PMID: 39833973
- 4. van Dongen KCW et al.. 2021. An in vitro model for microbial fructoselysine degradation shows substantial interindividual differences in metabolic capacities of human fecal slurries.. Toxicol In Vitro 72:105078 PMID: 33429044
- 5. Yamaguchi H et al.. 2024. Glucoselysine, a unique advanced glycation end-product of the polyol pathway and its association with vascular complications in type 2 diabetes.. J Biol Chem 300(7):107479 PMID: 38879006
- 6. Mrosewski I et al.. 2025. Menaquinone-7 Supplementation Increases Multiple Advanced Glycation End-Products and Oxidation Markers in Zucker Diabetic Fatty Rats.. Nutrients 17(17) PMID: 40944124
- 7. Wiame E et al.. 2004. Fructoselysine 3-epimerase, an enzyme involved in the metabolism of the unusual Amadori compound psicoselysine in Escherichia coli.. Biochem J 378(Pt 3):1047-52 PMID: 14641112
- 8. Van Schaftingen E et al.. 2012. Enzymatic repair of Amadori products.. Amino Acids 42(4):1143-50 PMID: 20967558
