title: Characterization of a D-psicose-producing enzyme, D-psicose 3-epimerase, from Clostridium sp.
abstract: The gene coding for D-psicose 3-epimerase (DPEase) from Clostridium sp. BNL1100 was cloned and expressed in Escherichia coli. The recombinant enzyme was purified by Ni-affinity chromatography. It was a metal-dependent enzyme and required Co(2+) as optimum cofactor. It displayed catalytic activity maximally at pH 8.0 and 65 °C (as measured over 5 min). The optimum substrate was D-psicose, and the K m, turnover number (k cat), and catalytic efficiency (k cat/K m) for D-psicose were 227 mM, 32,185 min(-1), and 141 min(-1 )mM(-1), respectively. At pH 8.0 and 55 °C, 120 g D-psicose l(-1) was produced from 500 g D-fructose l(-1) after 5 h.
authors: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China. wmmu@jiangnan.edu.cn
authors: Wanmeng
authors: W
authors: Mu
authors: Wenli
authors: W
authors: Zhang
authors: Dan
authors: D
authors: Fang
authors: Leon
authors: L
authors: Zhou
authors: Bo
authors: B
authors: Jiang
authors: Tao
authors: T
authors: Zhang
mesh_terms: D002413:Cations, Divalent / Q000378:metabolism; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics; D003035:Cobalt / Q000378:metabolism; D003067:Coenzymes / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005632:Fructose / Q000378:metabolism*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019998:Racemases and Epimerases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
chemical_list: D002413:Cations, Divalent; D003067:Coenzymes; D011994:Recombinant Proteins; C003243:psicose; D005632:Fructose; D003035:Cobalt; D019998:Racemases and Epimerases