کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10236206 | 45140 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Production, purification and characterization of a minor form of xylanase from Aspergillus versicolor
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
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چکیده انگلیسی
A strain of Aspergillus versicolor produces a xylanolytic complex containing two components, the minor component being designated xylanase II. The highest production of xylanase II was observed in cultures grown for 5 days in 1% wheat bran as carbon source, at pH 6.5. Xylanase II was purified 28-fold by DEAE-Sephadex and HPLC GF-510 gel filtration. Xylanase II was a monomeric glycoprotein, exhibiting a molecular mass of 32 kDa with 14.1% of carbohydrate content. Optimal pH and temperature values for the enzyme activity were about 6.0-7.0 and 55 °C, respectively. Xylanase II thermoinactivation at 50 °C showed a biphasic curve. The ions Hg2+, Cu2+ and the detergent SDS were strong inhibitors, while Mn2+ ions and dithiothreitol were stimulators of the enzyme activity. The enzyme was specific for xylans, showing higher specific activity on birchwood xylan. The Michaelis-Menten constant (Km) for birchwood xylan was estimated to be 2.3 mg mlâ1 while maximal velocity (Vmax) was 233.1 μmol mgâ1 minâ1 of protein. The hydrolysis of oat spelt xylan released only xylooligosaccharides.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Process Biochemistry - Volume 40, Issue 1, January 2005, Pages 359-364
Journal: Process Biochemistry - Volume 40, Issue 1, January 2005, Pages 359-364
نویسندگان
Eleonora Cano Carmona, Mauricio Batista Fialho, Ãrika Bicalho Buchgnani, Glauciane Danusa Coelho, Márcia Regina Brocheto-Braga, João AtıÌlio Jorge,