| 摘要: |
| 采用硫酸铵盐析、Phenyl-Sepharose CL-4B疏水层析、Sephadex G-50凝胶层析和DEAE-Sepharose fast flow阴离子交换层析等分离技术,从宇佐美曲霉(Aspergillus usamii)固态培养物浸出液中分离出一种SDS-PAGE电泳纯木聚糖酶组分,其最终的收率为19.0％,纯化倍数为26.9。该木聚糖酶的相对分子质量20.7 ku,等电点pl5.0,含糖量0.42％;该酶的最适作用温度为50 ℃,在50 ℃以下较稳定;最适作用pH 5.0,在pH 5.5～9.0时较稳定;Ca2+对该酶活性有一定的激活作用,而Pb2+,Sn2+,Cu2+,Al3+则有较强的抑制作用。以桦木木聚糖为底物,测得该酶的Km值和Vmax分别为3.5 mg/mL和5 000 μmol/(min·mg)。 |
| 关键词: 宇佐美曲霉 木聚糖酶 纯化 性质 |
| DOI： |
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| Studies on purification and properties of xylanase |
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| Abstract: |
| An component of xylanase was separated and purified by (NH4)2SO4 fractionation,Phenyl Sepharose CL-4B,Sephadex G-50 and DEAE Sepharose FF Ion exchange chromatography from the filtration of solid state culture medium of Aspergillus usamii.Its recovery rate and purification fold were respectively 19.0 % and 26.9.The xylanase was shown to be homogeneous by SDS PAGE.The molecular weight was estimated to be 20.7 ku by SDS PAGE chromatography.The isoelectric point pI 5.0 was determined by IEF-PAGE.Its carbohydrate content was 0.42 %,and its optimal temperature and optimum pH for the activity were 50 ℃ and 5.0 respectively.It showed good stability below 50 ℃ and was stable within pH 5.5-9.0.Its Km and Vmax were 3.5 mg/mL and 5 000 μmol/(min·mg) respectively with the xylan from beachwood as substrate. |
| Key words: Aspergillus usamii xylanase purification property |
