title: A new GH13 α-glucosidase from alkaliphilic Bacillus pseudofirmus 703 with both exo-α-l, 4-glucosidase and oligo-l, 6-glucosidase activities toward amylopectin.
abstract: Debranching of (1, 6)-α-linkages in starch is of great significance as it is widely used in different industries. In recent years, identifying a single potential enzyme that could debranch (1, 6)-α-linkages and cleave (1, 4)-α-linkages brought great interest as amylopectin possessed both (1, 4)-α- and (1, 6)-α-linkages. In the present study, a 64\,kDa exo-α-l, 4-glucosidase from Bacillus pseudofirmus 703, annotated as Amy112, was cloned and characterized. Biochemical analysis indicated that heterologous Amy112 expressed in Escherichia coli exhibited a high activity against amylopectin, with the optimal temperature and pH of 40°C and pH 7.0, respectively. Addition of K+ions improved the amy112 activity by 12%, but Li+, Ca2+and Mg2+ions showed no significant effect. Amy112 sequence homology revealed that it belonged to glycoside hydrolase family 13, showing 65% identity with α-glucosidase GSJ from Geobacillus sp. HTA-462. This is the first report indicating that Amy112 from B. pseudofirmus 703 belongs to GH13 enzyme family, having both exo-α-1, 4-glucosidase and oligo-l, 6-glucosidase activities. However, no transglycosylation activity was detected in LC-MS analysis. Amy112 would be of great significance of being utilized to debranch starch in different industries in a cost effective manner.
authors.affiliation: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, The College of Life Sciences, Hubei University, Wuhan 430062, China.
authors.forename: Shengchen
authors.initials: S
authors.lastname: Wang
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Qinhong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, The College of Life Sciences, Hubei University, Wuhan 430062, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, The College of Life Sciences, Hubei University, Wuhan 430062, China.
authors.forename: Zhenghui
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, The College of Life Sciences, Hubei University, Wuhan 430062, China. Electronic address: zhangguimin6@hotmail.com.
authors.forename: Guimin
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D000595:Amino Acid Sequence; D000687:Amylopectin / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008958:Models, Molecular; D011487:Protein Conformation; D012997:Solvents / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D008670:Metals; D012997:Solvents; D000687:Amylopectin; D000520:alpha-Glucosidases
keywords: Amylopectin; Exo-α-l, 4-glucosidase; Oligo-l, 6-glucosidase