Purification and Characterization of Extracellular β-Xylosidase and β-Glucosidase from Aspergillus fumigatus(Microbiology & Fermentation Industry)

概要

論文の詳細を見る
A β-xylosidase (β-D-xyloside xylohydrolase, EC 3.2.1.37) and β-glucosidase (β-D-glucoside glucohydrolase, EC 3.2.1.21) extracted from a wheat bran culture of Aspergillus fumigatus were purified up to 90-fold and 131-fold, respectively, by ammonium sulfate precipitation, gel filtration, ion exchange chromatography, and hydroxylapatite chromatography. Molecular weights of the β-xylosidase and β-glucosidase were 360,000 and 380,000, respectively, each consisting of four identical subunits. The isoelectric points of β-xylosidase and β-glucosidase were at pH 5.4 and 4.5, respectively. The optimum temperature for the β-xylosidase was 75℃, being stable up to 65℃ for 20 min and for the β-glucosidase was 65℃, being stable up to 60℃ for 20 min. The optimum pH for both enzymes was about 4.5, being stable between 2 and 8 at 50℃ for 20 min. Both enzymes were inhibited by Fe^<3+>, Cu^<2+>, Hg^<2+>, SDS, and p-chloromercuribenzoate. The apparent Michaelis constants of the β-xylosidase were 2.0 and 23.8 mM for p-nitrophenyl-β-xyloside and xylobiose, respectively, and those of the β-glucosidase were 1.4, 11.4, and 24.8mM for p-nitrophenyl-β-glucoside, gentiobiose, and cellobiose, respectively. To produce xylose from crude xylooligosaccharides prepared by steam-explosion of cotton seed waste (DP<__-10, 53%, total sugars=150g/liter), the crude enzyme from A. fumigatus (β-xylosidase activity=14.7 units/ml, xylanase activity=20units/ml) could hydrolyze the substrate at 55℃ and pH 4.5 resulting in almost complete conversion to xylose (160g/liter).
社団法人日本農芸化学会の論文
1986-07-23

Purification and Characterization of Extracellular β-Xylosidase and β-Glucosidase from Aspergillus fumigatus(Microbiology & Fermentation Industry)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク