title: Novel substrate specificity of D-arabinose isomerase from Klebsiella pneumoniae and its application to production of D-altrose from D-psicose.
abstract: d-Arabinose isomerase from Klebsiella pneumoniae 40bXX was purified 12-fold with a 62.5% yield indicated by its electrophoretic homogeneity. The purified enzyme showed the highest activities toward d-arabinose and l-fucose as substrates at optimum conditions (50 mM glycine-NaOH, pH 9.0, 40 degrees C). The enzyme had a broad range of substrate specificities toward various d/l-aldoses, i.e., d-arabinose, l-fucose, d/l-xylose, d-mannose, d/l-lyxose, l-glucose, d-altrose and d/l-galactose. The equilibrium ratios between d-arabinose and d-ribulose, l-fucose and l-fuculose, d-altrose and d-psicose, and l-galactose and l-tagatose were 90:10, 90:10, 13:87 and 25:75, respectively. Using a combination of the immobilized d-tagatose 3-epimerase and d-arabinose isomerase, we achieved the production of d-altrose from d-fructose in a batch reactor. We successfully produced approximately 12 g of d-altrose from 200 g of d-fructose in a reaction series with an overall yield of 6%. The product obtained was confirmed to be d-altrose by HPLC and (13)C-NMR. To the best of our knowledge, this is the first report on the production of d-altrose from a cheap sugar, d-fructose, using an enzymatic method.
authors.affiliation: Department of Biochemistry and Food Science, Faculty of Agriculture and Rare Sugar Research Center, Kagawa University, Miki-Cho, Kagawa 761-0795, Japan.
authors.forename: Buetusiwa Thomas
authors.initials: BT
authors.lastname: Menavuvu
authors.forename: Wayoon
authors.initials: W
authors.lastname: Poonperm
authors.forename: Kosei
authors.initials: K
authors.lastname: Takeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Morimoto
authors.forename: Tom Birger
authors.initials: TB
authors.lastname: Granström
authors.forename: Goro
authors.initials: G
authors.lastname: Takada
authors.forename: Ken
authors.initials: K
authors.lastname: Izumori
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000302:isolation & purification / Q000378:metabolism*; D005632:Fructose / Q000378:metabolism*; D006601:Hexoses / Q000096:biosynthesis*; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D006601:Hexoses; C003243:psicose; D005632:Fructose; D019747:Aldose-Ketose Isomerases; C019714:D-arabinose isomerase