title: Expression, enzymatic characterization, and high-level production of glucose isomerase from Actinoplanes missouriensis CICIM B0118(A) in Escherichia coli.
abstract: High-level production of recombinant glucose isomerase (rGI) is desirable for lactulose synthesis. In this study, the xylA gene encoding glucose isomerase from Actinoplanes missouriensis CICIM B0118(A) was cloned and expressed in E. coli BL21(DE3), and high-level production was performed by optimization of the medium composition. rGI was purified from a recombinant E. coli BL21(DE3) and characterized. The optimum pH value of the purified enzyme was 8.0 and it was relatively stable within the pH range of 7.0-9.0. Its optimum temperature was around 85 degrees C, and it exhibited good thermostability when the temperature was lower than 90 degrees C. The maximum enzyme activity required the presence of both Co2+ and Mg2+, at the concentrations of 200 microM and 8 mM, respectively. With high-level expression and the simple one-step chromatographic purification of the His-tagged recombinant enzyme, this GI could be used in industrial production of lactulose as a potential economic tool.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.forename: Ruijin
authors.initials: R
authors.lastname: Yang
authors.forename: Xiao
authors.initials: X
authors.lastname: Hua
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Wenbin
authors.initials: W
authors.lastname: Zhang
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000096:biosynthesis*; D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration
chemical_list: D017931:DNA Primers; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase