Amylosucrase: A Versatile Sucrose-Utilizing Transglucosylase for Glycodiversification

Abstract

Carbohydrates are undoubtedly the most abundant organic compounds in nature, with diverse chemical structures and biological functions. The diversity of carbohydrates is determined by a series of enzymes, named Carbohydrate-Active enZymes (CAZymes), that catalyze the assembly, cleavage, and modification of carbohydrates (Lombard et al. 2014). CAZymes can be classified into glycoside hydrolases (GH), glycosyltransferases (GT), polysaccharide lyases (PL), carbohydrate esterases (CE), carbohydrate binding modules (CBM), and auxiliary activities (AA) which accounts for 47%, 36%, 1%, 5%, 10%, and 1%, respectively (André et al. 2014). With the rapidly increased number of CAZymes members, many facile enzyme-based synthetic routes to complex carbohydrates can be accessible. However, numerous enzymatic or chemo-enzymatic pathways are still hampered by the lack of some desirable catalysts, and thus CAZymes with requisite properties and specificities are urgently demanded (Benkoulouche et al. 2019). Among the CAZymes, GH family enzymes attract increasing attention in terms of glycodiversification recently, owing to their ability to utilize abundant biomasses such as starches and sucrose instead of expensive nucleotide-active sugars as donor substrates.