School of Minerals Processing and Bioengineering, Central South University, South Lushan Road 932, Changsha, 410083, People's Republic of China.
World J Microbiol Biotechnol. 2013 Nov;29(11):2095-103. doi: 10.1007/s11274-013-1374-5. Epub 2013 May 14.
A putative endo-1,4-β-D-xylanohydrolase gene xyl11 from Aspergillus niger, encoding a 188-residue xylanase of glycosyl hydrolase family 11, was constitutively expressed in Pichia pastoris. The recombinant Xyl11 exhibited optimal activity at pH 5.0 and 50 °C, and displayed more than 68 % of the maximum activity over the temperature range 35-65 °C and 33 % over the pH range 2.2-7.0. It maintained more than 40 % of the original activity after incubation at 90 °C (pH 5.0) for 10 min and more than 75 % of the original activity after incubation at pH 2.2-11.0 (room temperature) for 2 h. The specific activity, K m and V max of purified Xyl11 were 22,253 U mg(-1), 6.57 mg ml(-1) and 51,546.4 μmol min(-1) mg(-1). It could degrade xylan to a series of xylooligosaccharides and no xylose was detected. The recombinant enzyme with high stability and catalytic efficiency could work over wide ranges of pH and temperature and thus has the potential for various industrial applications.
从黑曲霉中克隆得到一个假定的内切 1,4-β-D-木聚糖酶基因 xyl11，其编码的木聚糖酶属于糖苷水解酶家族 11，在毕赤酵母中组成型表达。重组 Xyl11 在 pH5.0 和 50°C 时表现出最佳活性，在 35-65°C 的温度范围内具有超过 68%的最大活性，在 pH2.2-7.0 的范围内具有 33%的最大活性。它在 90°C（pH5.0）下孵育 10 分钟后仍保持超过 40%的原始活性，在 pH2.2-11.0（室温）下孵育 2 小时后仍保持超过 75%的原始活性。纯化的 Xyl11 的比活性、K m 和 V max 分别为 22,253 U mg(-1)、6.57 mg ml(-1)和 51,546.4 μmol min(-1) mg(-1)。它可以将木聚糖降解为一系列低聚木糖，没有检测到木糖。该重组酶具有高稳定性和催化效率，能够在宽 pH 和温度范围内工作，因此具有各种工业应用的潜力。
