title: Purification and characterization of a highly selective sucrose isomerase from Erwinia rhapontici NX-5.
abstract: A highly selective sucrose isomerase (SIase) was purified to homogeneity from the cell-free extract of Erwinia rhapontici NX-5 with a recovery of 27.7% and a fold purification of 213.6. The purified SIase showed a high specific activity of 427.1 U mg(-1) with molecular weight of 65.6 kDa. The K (m) for sucrose was 222 mM while V (max) was 546 U mg(-1). The optimum pH and temperature for SIase activity were 6.0 and 30 °C, respectively. The purified SIase was stable in the temperature range of 10-40 °C and retained 65% of the enzyme activity after 2 weeks' storage at 30 °C. The SIase activity was enhanced by Mg(2+) and Mn(2+), inhibited by Ca(2+), Cu(2+), Zn(2+), and Co(2+), completely inhibited by Hg(2+) and Ag(2+). The purified SIase was strongly inhibited by SDS, while partially inhibited by dimethylformamide, tetrahydrofuran, and PMSF. Additionally, glucose and fructose acted as competitive inhibitors for purified SIase.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing University of Technology, No. 5 New Model Road, Nanjing, 210009, Jiangsu, People's Republic of China.
authors.forename: Ben
authors.initials: B
authors.lastname: Ren
authors.forename: Sha
authors.initials: S
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Xiao-Hai
authors.initials: XH
authors.lastname: Feng
authors.forename: Heng
authors.initials: H
authors.lastname: Cai
authors.forename: Qi
authors.initials: Q
authors.lastname: Ye
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D002118:Calcium / Q000737:chemistry; D004126:Dimethylformamide / Q000737:chemistry; D004885:Erwinia / Q000201:enzymology*; D005632:Fructose / Q000378:metabolism; D005663:Furans / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry; D008970:Molecular Weight; D017830:Octoxynol / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D005663:Furans; D019216:Metals, Heavy; D005632:Fructose; D012967:Sodium Dodecyl Sulfate; C018674:tetrahydrofuran; D013395:Sucrose; D004126:Dimethylformamide; D017830:Octoxynol; D005964:Glucosyltransferases; C116853:sucrose isomerase; D008274:Magnesium; D005947:Glucose; D002118:Calcium