title: Cloning and characterization of a new ribitol dehydrogenase from Providencia alcalifaciens RIMD 1656011.
abstract: BACKGROUND
  A new ribitol dehydrogenase gene was cloned from Providencia alcalifaciens RIMD 1656011 and expressed in Escherichia coli BL21. This study aimed to purify and characterize the ribitol dehydrogenase from P. alcalifaciens RIMD 1656011 and investigate its substrate specificity for potential use as an industrial enzyme.
  
  
  RESULTS
  The protein was purified by nickel affinity chromatography. The molecular mass of the purified enzyme was determined as ∼25 000 and 26 650 Da through sodium dodecyl sulfate polyacrylamide gel electrophoresis and liquid chromatography/mass spectrometry respectively. The result for native molecular mass (104 kDa) suggested that the enzyme functions as a tetramer. Optimum activity of the enzyme was determined at pH 10.0 and a temperature of 35 °C. Regarding its thermal stability, the enzyme retained 72, 72, 48 and 0% of its initial activity after 4 h at 25, 30, 40 and 50 °C respectively. The Km , kcat and kcat /Km values of the enzyme for the substrate ribitol were determined as 13.9 mmol L(-1) , 10.0 s(-1) and 0.71 L mmol(-1) s(-1) respectively. The Km of NAD(+) was 0.042 mmol L(-1) .
  
  
  CONCLUSIONS
  The substrate specificity indicated that the ribitol dehydrogenase from P. alcalifaciens RIMD 1656011 can be used for direct production of allitol from d-fructose without any by-product formation. © 2015 Society of Chemical Industry.
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
authors.forename: Hinawi Am
authors.initials: HA
authors.lastname: Hassanin
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
authors.forename: Wanmeng
authors.initials: W
authors.lastname: Mu
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D007700:Kinetics; D011532:Providencia / Q000201:enzymology*; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D013401:Sugar Alcohol Dehydrogenases; C022529:ribitol 2-dehydrogenase
keywords: Providencia alcalifaciens; allitol; ribitol dehydrogenase; ribulose