耐冷皮壳正青霉一种木聚糖酶的纯化与性质研究

Purification and characterization of a xylanase from psychrotrophic Eupenicillium crustaceum

研究了耐冷皮壳正青霉Eupenicillium crustaceum一种木聚糖酶的纯化和酶学性质。采用硫酸铵沉淀和阴离子交换层析的方法,从耐冷皮壳正青霉液体发酵液中分离纯化出一种亚基分子量35kDa的木聚糖酶。酶学性质研究表明,酶的最适pH值为5.5,在pH4.5-6.5范围内具有较高的催化活性。最适温度为50℃,20℃下酶活为最高酶活的40%。Ag+和Fe2+大幅度提高木聚糖酶的酶活,而Mn2+和Hg2+强烈抑制木聚糖酶的活性。同时,该木聚糖酶具有严格的底物特异性。

A xylanase from psychrotrophic Eupenicillium crustaceum was purified and characterized.The xylanase was purified to homogeneity by ammonium precipitation and anion-exchange chromatography and its subunit molecular mass was estimated to be 35kDa by SDS-PAGE.The xylanase showed apparent optimal activity at pH 5.5 and 50℃.It retained more than 80% of its maximum activity at pH 4.5-6.5 and retainded 40% of its maximum activity at 20℃.The enzyme was greatly activated by Ag＋ and Fe2＋,and strongly inhibited by Mn2＋ and Hg2＋.The xylanase displayed a strict substrate specificity.