降解菌DDS-1产3-AC-DON氧化酶的酶学特性

【目的】研究脱氧雪腐镰刀菌烯醇（deoxynivalenol，DON）降解菌Devosia sp. DDS-1产生的3-AC-DON氧化酶的酶学特性，掌握DDS-1降解3-AC-DON到3-酮基-DON特性，为该酶的开发应用奠定理论基础。【方法】LG培养基培养DON毒素降解菌Devosia sp. DDS-1后，用PBS离心洗涤菌体后采用超声波破碎，用硫酸铵沉淀菌体破碎液获得粗酶液；然后在不同的酶反应体系中检测3-AC-DON氧化酶的酶活性。【结果】降解菌DDS-1产生3-AC-DON氧化酶的最适条件为：pH 7.0、25℃、培养36 h；该酶酶反应的最适温度为35℃，最适反应pH为7.0；该酶在20—40℃，pH 5.0—9.0的范围内能保持80%以上的酶活性；大多数金属离子在浓度为0.2—2 mmol•L-1对3-AC-DON氧化酶有促进作用；乙二胺四乙酸（EDTA）对该酶活性有抑制作用；酶的定域试验结果显示该酶为胞内酶；DDS-1产生的粗酶液能很好地降解小麦中的DON、3-AC-DON毒素。【结论】Devosia sp. DDS-1产生的3-AC-DON氧化酶的酶学特性研究表明，DDS-1产生的3-AC-DON氧化酶具有较好的温度和酸碱稳定性，该酶反应需要金属离子作为辅因子。

Enzymatic Characteristics of 3-Acetyl Deoxynivalenol Oxidase by Devosia sp. DDS-1

【Objective】 The objective of this study is to investigate the enzymatic characteristics of 3-acetyl deoxynivalenol oxidase (3-AC-DON oxidase), understand the degradation characteristics of 3-acetyl deoxynivalenol by Devosia sp. DDS-1, and realize the application of the enzyme.【Method】After being cultured in LG medium , the strain DDS-1 was centrifuged and washed by PBS, and then broken by ultrasonic treatment. The crude enzyme of DDS-1 was obtained by ammonium sulfate precipitation. The enzymatic activity of 3-AC-DON oxidase was then detected in different enzyme reaction systems. 【Result】 The optimal 3-AC-DON oxidase production conditions for DDS-1 were 25℃, pH 7.0 and 36 hours in LG medium. The optimum reaction conditions for the 3-AC-DON oxidase in DDS-1 were 35℃, pH 7.0. The enzymatic activity could be maintained above 80% from 20 to 40℃ and in the range of pH 5.0 to 9.0. Most metal ions at a concentration from 0.2 to 2 mmol•L-1 could promote the enzymatic activity. Ethylenediamine tetraacetic acid (EDTA) inhibited the enzyme activity on the contrary. The crude enzyme produced by DDS-1 could degrade DON, 3-AC-DON in wheat.【Conclusion】The enzymatic characteristics of 3-AC-DON oxidase produced by Devosia sp. DDS-1 was studied in this paper. The results showed that Devosia sp. DDS-1 can produce 3-AC-DON oxidase with good temperature and pH stability, and the enzyme requires metal ions as cofactor.