Amylosucrase as a transglucosylation tool: From molecular features to bioengineering applications

Amylosucrase (EC 2.4.1.4, ASase), an outstanding sucrose-utilizing transglucosylase in the glycoside hydrolase family 13, can produce glucans with only α-1,4 linkages. Generally, on account of a double-displacement mechanism, ASase can catalyze polymerization, isomerization, and hydrolysis reactions with sucrose as the sole substrate, and has transglycosylation capacity to attach glucose molecules from sucrose to extra glycosyl acceptors. Based on extensive enzymology research, this review presents the characteristics of various ASases, including their microbial metabolism, preparation, and enzymatic properties, and exhibits structure-based strategies in the improvement of activity, specificity, and thermostability. As a vital transglucosylation tool of producing sugars, carbohydrate-based bioactive compounds, and materials, the bioengineering applications of ASases are also systematically summarized.