Characterization and mechanism of action of Microbacterium imperiale glucan 1,4-α-maltotriohydrolase

Abstract

In this study, glucan 1,4-α-maltotriohydrolase (AMTS) from Microbacterium imperiale was purified and characterized. Hydrolysis by AMTS was affected by starch structure (e.g., amylose versus amylopectin) and hydrolysis time. During the initial phase of hydrolysis of maltooligosaccharides (G4-G7), AMTS displayed a unique transfer specificity to the transfer of maltotriosyl units. After extensive hydrolysis, maltotriose became the major end product, followed by glucose and maltose. Maltotetraose (G4) was the smallest donor in transglycosylation reactions by AMTS. This is the first study that reports transglycosylation activity of AMTS on maltooligosaccharides. The results of this study suggest that high purity maltotriose can be produced by the hydrolytic action of AMTS on starch.

Keywords: AMTS; CS; CSAM; CSAP; Corn starch; DM; DP; G1–G7; Glucan 1,4-α-maltotriohydrolase; Maltooligosaccharides; Maltotriose; PM; Transglycosylation; corn amylopectin; corn amylose; corn starch; degree of polymerization; degree of starch hydrolyzed into maltotriose; glucan 1,4-α-maltotriohydrolase; glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose; percentage of maltotriose in G1–G7.