Abstract: As a biocatalystase, acid trehalase is widely used in biological industry. It is very important to exploit new acid trehalase with excellent enzymatic properties. In this study, an acid trehalase gene (TreA) from Bispora sp. MEY-1 was successfully cloned and expressed in Pichia pastoris GS115. The enzymatic properties of purified trehalase TreA were identified. The optimum pH was 4.0, and the relative activity maintained over 60% under the range of pH 2.2~5.0. The relative activity of purified enzyme was more than 88% after treated for 1 h under pH 1.0~4.0, which exhibited the good acid stability. The optimum temperature of purified enzyme was 60 ℃, which was enzyme with medium-high temperature resistance. The specific activity of purified enzyme was 1 913 U·mg^-1, and its Km and Vmax were 0.67 mg·mL^-1 and 119 μmol·min^-1·mg^-1, respectively. Moreover, the effects of different mental ions or chemical reagents, and the protease resistances on the purified enzyme activity were also evaluated.

Key words: Bispora sp. MEY-1, acid trehalase, heterologous expression, characterization

摘要： 酸性海藻糖酶作为生物催化剂在生物工业中广泛应用，挖掘酶学性质优良的酸性海藻糖基因具有重要意义。从Bispora sp. MEY-1中成功克隆出一个酸性海藻糖酶基因TreA，并在毕赤酵母GS115中实现高效表达。对纯化后的酸性海藻糖酶TreA进行酶学性质鉴定，其最适pH为4.0，在pH 2.2~5.0范围内，该酶能够维持60%以上的酶活力。TreA在偏酸条件下稳定效果比较好，在pH 1.0~4.0条件下处理1 h，可以剩余88%以上的酶活力。TreA的最适温度为60 ℃，在40~70 ℃之间都可以维持50%以上的酶活力，属于中高温酶。重组海藻糖酶TreA的比活为1 913 U·mg^-1，动力学参数Km和Vmax分别为0.67 mg·mL^-1和119 μmol·min^-1·mg^-1。同时，还评估了不同金属离子或化学试剂对纯海藻糖酶TreA的酶活性影响及其蛋白酶抗性。极大丰富了海藻糖酶基因资源，促进了其在生物工业中的应用。

关键词: Bispora sp. MEY-1, 酸性海藻糖酶, 异源表达, 酶学性质鉴定