title: Characterisations of Lactobacillus reuteri SK24.003 glucansucrase: Implications for α-gluco-poly- and oligosaccharides biosynthesis.
abstract: Glucansucrase was obtained from Lactobacillus reuteri SK24.003 and its characterizations and in vitro biosynthesis for glucose polymer and oligosaccharides were investigated. The final specific activity of glucansucrase was 1.3IU/mg protein with 8.6-fold purification and 8.7% recovery. The molecular weight of purified enzyme was 166.0kDa. The glucansucrase exhibited optimum activity at 30-35°C, whereas the maximum activity was obtained at pH 5.0-5.5. The double-charged ions including Mg2+, Mn2+, Ni2+, Co2+, Ca2+, Fe2+and Zn2+activated the glucansucrase activities and Ca2+ion highly stimulated the activity by approximately 4 times. Km, Vmaxand kcatof purified glucansucrase were calculated to be 3.7mM, 0.8IU/mg and 18.21/s, respectively. For in vitro biosynthesis, glucansucrase synthesized 1,6-,1,4-α-d-glucan with a molecular weight of 2.5×107g/mol from sucrose as initial primer. Moreover, maltose acceptor-products synthesized by glucansucrase were composed of panose, maltotriose, maltotetraose, tetrasaccharide and pentasaccharide products analogues with an α-1,4/α-1,6 alternating structure.
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China. Electronic address: miaoming@jiangnan.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Miao
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China; Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ont. N1G 5C9, Canada.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
mesh_terms: D005936:Glucans / Q000096:biosynthesis*; D016695:Glycosyltransferases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D052200:Limosilactobacillus reuteri / Q000201:enzymology*; D008970:Molecular Weight; D009844:Oligosaccharides / Q000096:biosynthesis*; D012997:Solvents; D013696:Temperature
chemical_list: D005936:Glucans; D009844:Oligosaccharides; D012997:Solvents; D016695:Glycosyltransferases; C033837:alternansucrase
keywords: Enzymological property; Glucan biosynthesis; Glucansucrase; Lactobacillus reuteri SK24.003; Structure