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 C,在50 C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5000 μmol／(min·mg)。
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 000μmol/（min·mg） respectively with the xylan from beachwood as substrate.
出处
《西北农林科技大学学报（自然科学版）》
CSCD
北大核心
2006年第2期71-76,共6页
Journal of Northwest A&F University(Natural Science Edition)
关键词
宇佐美曲霉
木聚糖酶
纯化
性质
Aspergillus usamii
xylanase
purification
property
