Purification, characterization and gene analysis of a new α-glucosidase from shiraia sp. SUPER-H168

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• 作者：Ruijie Gao ; Huaxiang Deng ; Zhengbing Guan ; Xiangru Liao…
• 关键词：α ; glucosidase ; Characterization ; Gene analysis ; Purification ; Shiraia sp. SUPER ; H168 ; Solid ; state fermentation
• 刊名：Annals of Microbiology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：67
• 期：1
• 页码：65-77
• 全文大小：
• 刊物主题：Microbiology; Microbial Genetics and Genomics; Microbial Ecology; Mycology; Medical Microbiology; Applied Microbiology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1869-2044
• 卷排序：67

文摘

A new α-glucosidase from Shiraia sp. SUPER-H168 under solid-state fermentation was purified by alcohol precipitation and anion-exchange and by gel filtration chromatography. The optimum pH and temperature of the purified α-glucosidase were 4.5 and 60 °C, respectively, using p-nitrophenyl-α-glucopyranoside (α-pNPG) as a substrate. Ten millimoles of sodium dodecyl sulfate, Fe2+, Cu2+, and Ag+ reduced the enzyme activity to 0.7, 7.6, 26.0, and 6.2 %, respectively, of that of the untreated enzyme. The K_m, V_max, and k_cat/K_m of the α-glucosidase were 0.52 mM, 3.76 U mg−1, and 1.3 × 104 L s−1 mol−1, respectively. K_m with maltose was 0.62 mM. Transglycosylation activities were observed with maltose and sucrose as substrates, while there was no transglycosylation with trehalose. DNA and its corresponding full-length cDNA were cloned and analyzed. The α-glucosidase coding region consisted of a 2997-bp open reading frame encoding a 998-amino acid protein with a 22-amino acid signal peptide; one 48-bp intron was located. The α-glucosidase was a monomeric protein with a predicted molecular mass of 108.2 kDa and a predicted isoelectric point of 5.08. A neighbor-joining phylogenetic tree demonstrated that Shiraia sp. SUPER-H168 α-glucosidase is an ascomycetes α-glucosidase. This is the first report of α-glucosidase from a filamentous fungus that had good glycoside hydrolysis with maltose and α-pNPG, transglycosylation and conversion activity of maltose into trehalose.