Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd, Shanghai 201106, China.
Mol Biol Rep. 2011 Nov;38(8):4991-7. doi: 10.1007/s11033-010-0644-7. Epub 2010 Dec 15.
In recent years, the biotechnological use of xylanases has grown remarkably. To efficiently produce xylanase for food processing and other industry, a codon-optimized recombinant xylanase gene from Streptomyces sp. S38 was synthesized and extracellularly expressed in Pichia pastoris under the control of AOX1 promoter. SDS-PAGE and activity assay demonstrated that the molecular mass of the recombinant xylanase was estimated to be 25 kDa, the optimum pH and optimum temperature were 5.5 and 50°C, respectively. In shake flask culture, the specific activity of the xylanase activity was 5098.28 U/mg. The K ( m ) and V ( max ) values of recombinant xylanase were 11.0 mg/ml and 10000 μmol min(-1) mg(-1), respectively. In the presence of metal ions such as Ca(2+), Cu(2+), Cr(3+) and K(+), the activity of the enzyme increased. However, strong inhibition of the enzyme activity was observed in the presence of Hg(2+). This is the first report on the expression properties of a recombinant xylanase gene from the Streptomyces sp. S38 using Pichia pastoris. The attractive biochemical properties of the recombinant xylanase suggest that it may be a useful candidate for variety of commercial applications.
近年来，木聚糖酶的生物技术应用有了显著的增长。为了高效生产用于食品加工和其他工业的木聚糖酶，我们合成了来自链霉菌 S38 的经密码子优化的重组木聚糖酶基因，并在毕赤酵母中通过 AOX1 启动子进行了细胞外表达。SDS-PAGE 和活性测定表明，重组木聚糖酶的分子量估计为 25 kDa，最适 pH 和最适温度分别为 5.5 和 50°C。在摇瓶培养中，木聚糖酶的比活为 5098.28 U/mg。重组木聚糖酶的 K(m)和 V(max)值分别为 11.0 mg/ml 和 10000 μmol min(-1) mg(-1)。在存在 Ca(2+)、Cu(2+)、Cr(3+)和 K(+)等金属离子的情况下，酶的活性增加。然而，在存在 Hg(2+)的情况下，酶的活性受到强烈抑制。这是首次报道使用毕赤酵母表达来自链霉菌 S38 的重组木聚糖酶基因的表达特性。重组木聚糖酶具有吸引人的生化特性，表明它可能是各种商业应用的有用候选者。
