α-Galactosidase/Sucrose Kinase (AgaSK), a Novel Bifunctional Enzyme from the Human Microbiome Coupling Galactosidase and Kinase Activities

Abstract : Background: Raffinose, an abundant carbohydrate in plants, is degraded into galactose and sucrose by intestinal microbial enzymes. Results: AgaSK is a protein coupling galactosidase and sucrose kinase activity. The structure of the galactosidase domain sheds light onto substrate recognition. Conclusion: AgaSK produces sucrose-6-phosphate directly from raffinose. Significance: Production of sucrose-6-phosphate directly from raffinose points toward a novel glycolytic pathway in bacteria.