镰刀菌Q7-31T内切葡聚糖酶Egn20的分离纯化鉴定及酶学特性

Purification， identification and characterization of an endoglucanase Egn20 from Fusarium sp.Q7-31T

摘要:

摘要:【目的】从镰刀菌Q7-31T燕麦秸秆诱导发酵的粗酶液中分离、纯化并鉴定内切葡聚糖酶，研究其酶学特性。为丰富和完善镰刀菌的酶系信息提供理论支持。【方法】以燕麦秸秆为碳源诱导发酵培养菌株，采用Sephacry S-100凝胶柱层析和DEAE琼脂糖弱阴离子交换柱层析对粗酶液进行分离纯化得到内切葡聚糖酶Egn20，随后对其进行了酶学性质分析和串联质谱鉴定。【结果】分离纯化得到内切葡聚糖酶Egn20，其分子量为55.37 kDa，等电点为7.44;酶学特性结果表明:Egn20对羧甲基纤维素的最适反应温度为40 ℃，最适pH为6.0，该酶在45 ℃和弱酸性环境下较稳定，Fe2+对其有激活作用，Na+、Ca2+、Mg2+、Zn2+和K+抑制该酶活性，Hg2+使该酶失活;酶学特性和串联质谱鉴定的结果表明Egn20属于GH7家族。【结论】从镰刀菌Q7-31T粗酶液中分离纯化得到内切葡聚糖酶Egn20，并对其进行了酶学性质的研究和串联质谱鉴定，结果表明Egn20为GH7家族内切葡聚糖酶。本研究为丰富和完善镰刀菌的酶系信息提供了理论和数据支持。

Abstract:

Abstract:［Objective］The endoglucanase from Fusarium sp.Q7-31T was isolated，purified，identified and characterized to provide data for enzyme system of Fusarium sp.［Methods］Strain was cultured in liquid fermentation with oat strawas carbon source，the endoglucanase was purified by using Sephacry S-100 chromatography and DEAE-sepharose ionexchange column chromatography and the enzymatic properties were studied．The protein was identified using MADILTOF-TOF.［Results］ An endoglucanase was purified and named Egn20． The molecular weight was 55.37 kDa and isoelectric point (pI) was 7.44． Egn20 had optimal activity with carboxymethyl cellulose at 40 ℃ and pH6. 0，stabilized at 45 ℃ and pH5.0－7.0，activated by Fe2+，inhibited by Na+，Ca2+，Mg2+，Zn2+，K + and inactivated by Hg2+．The enzymatic properties and MADIL-TOF-TOF results suggested that Egn20 belongs to GH7 family.［Conclusion］ Our results may provide important data for the study of Fusarium sp．enzyme system.