Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab, India.
Bioresour Technol. 2010 Nov;101(22):8834-42. doi: 10.1016/j.biortech.2010.06.071. Epub 2010 Jul 13.
Two xylanases, MFX I and MFX II, from the thermophilic fungus Malbranchea flava MTCC 4889 with molecular masses of 25.2 and 30kDa and pIs of 4.5 and 3.7, respectively were purified to homogeneity. The xylanases were optimally active at pH 9.0 and at 60 degrees C, exhibited a half-life of 4h at 60 degrees C, and showed distinct mode of action and product profiles when applied to birchwood, oat spelt, and larchwood xylan, and to wheat and rye arabinoxylan. The xylanases were most active on larchwood xylan with K(m) values of 1.25 and 3.7mg/ml. K(cat)/K(m) values suggested that the xylanases preferentially hydrolyzed rye arabinoxylan. LC-MS/MS (liquid chromatography/mass spectrometry) analysis of tryptic digests of MFX I and MFX II revealed similarity with known fungal xylanases and suggests that that they belonged to the GH 11 and 10 glycosyl hydrolase super families, respectively. These xylanases can potentially be used in enzyme-assisted bleaching of the pulp derived from agro-residues, as well as production of xylooligosaccharides for pre-biotic functional food applications.
两种木聚糖酶，MFX I 和 MFX II，来自嗜热真菌 Malbranchea flava MTCC 4889，分子量分别为 25.2 和 30kDa，等电点分别为 4.5 和 3.7。这两种木聚糖酶均被纯化至均一状态。木聚糖酶在 pH 9.0 和 60°C 下具有最佳活性，在 60°C 下半衰期为 4 小时，在应用于桦木、燕麦、落叶松木聚糖以及小麦和黑麦阿拉伯木聚糖时，表现出明显的作用方式和产物谱。木聚糖酶对落叶松木聚糖的活性最高，K(m) 值分别为 1.25 和 3.7mg/ml。K(cat)/K(m) 值表明，木聚糖酶优先水解黑麦阿拉伯木聚糖。MFX I 和 MFX II 的胰蛋白酶消化物的 LC-MS/MS（液相色谱/质谱）分析显示与已知真菌木聚糖酶具有相似性，并表明它们分别属于 GH 11 和 10 糖苷水解酶超家族。这些木聚糖酶可潜在地用于酶辅助处理源自农业残留物的纸浆的漂白，以及生产用于预生物功能性食品应用的木寡糖。
