Cyclodextrin-preferring glycoside hydrolases: properties and applications

Abstract Cyclodextrin-hydrolyzing enzymes are widespread in bacteria and archaea where they play their roles in carbohydrates metabolism. They were previously characterized as cyclodextrinases, neopullulanases and maltogenic amylases. In the Carbohydrate-Active enZyme (CAZy) database, most of these enzymes are grouped into the GH13_20 subfamily of the α-amylase family GH13. Here, we have summarized the information available on the substrate specificity, structural features, physiological roles and applications of cyclodextrin-preferring glycoside hydrolases. These enzymes form a distinct group in the α-amylase family. Members of this distinct group possess an extra extension at the N-terminus, which causes a modification of the active site geometry thus making these enzymes more specific for smaller molecules like cyclodextrins than for macromolecules such as starches or pullulan. Multi-substrate specificity, hydrolytic as well as transglycosylation activities make these enzymes attractive for applications in the food and pharmaceutical industries. We have tried here to collect information available on their biochemical properties, three-dimensional structures, physiological roles and potential applications.