【摘要】 从瓶霉Phialophora sp.P13菌株中克隆得到一个11家族的木聚糖酶基因,命名为xyn11P13。该基因ORF全长705 bp,共编码234个氨基酸和一个终止密码子,N端19个氨基酸为预测的信号肽序列。成熟蛋白在毕赤酵母中进行了重组表达,在摇床水平上木聚糖酶XYN11P13的表达量为11.8 U/mL。XYN11P13的最适pH为5.5,在pH 3.5～7.0可以保持80%以上的酶活性,在pH 4.0～10.0具有良好的pH稳定性。最适作用温度为65℃,并在60℃条件下保持稳定。以榉木木聚糖为底物,XYN11P13的比活,Km及Vmax值分别为205.3 U/mg,2.73 mg/mL,399.6μmol/min/mg。多数金属离子对XYN11P13酶活力没有明显的影响。因此,XYN11P13具潜在优势应用于食品与动物饲料工业。更多还原

【Abstract】 Xyn11P13,a glycoside hydrolase family 11 xylanse gene,was cloned from Phialophora sp.P13.The full-length gene consists of 705 bp and encodes 234 amino acids,including a putative signal peptide of 19 residues at N-terminus.The mature xylanase was expressed in Pichia pastoris.In shaker flask culture,XYN11P13 was produced with activity of 11.8 U/mL.XYN11P13 showed the optimal activity at pH 5.5,it retained >80.0% of the maximal activity at pH 3.5~7.0,and showed high stability over the pH range 4.0~10.0.The optimum temperature was 65℃,it retained 80% of the maximal activity at 75℃,and was stable at 60℃.The specific activity,K_m and V_max values towards beechwood xylan were 137 U/mg,6.9 mg/mL and 209 μmol/min/mg,respectively.XYN11P13 was strongly resistant to most metal ions.All these favorable properties make XYN11P13 attractive for potential applications in food and animal feed industries.更多还原