毕赤酵母异源表达β-葡聚糖酶酶学特性的研究

Characterization of endo-β-1,4-glucanase heterologously expressed in Pichia pastoris

根据酵母密码子的偏好性对来自某异源菌种的葡聚糖酶基因进行化学合成改造,用电转化方法整合到毕赤酵母基因组中进行表达,并对表达出的内切β-葡聚糖酶进行相关酶学特性研究。结果表明:酶的最适pH为4.5,最适温度为40℃C;酶的pH稳定性范围与缓冲溶液类型有关,为4.0—6.0;Al^(3+)对酶有激活作用,但Mn^(2+)和Cu^(2+)则会抑制酶的活性;此酶对羧甲基纤维素钠(CMC-Na)有较强的分解能力;胃蛋白酶对该酶有抑制作用。

The β-1,4-glucanase gene from Gibberella zeae was re-synthesized chemically according to the yeast bias condon and tansformed into Pichia pastoris by electroporation.The expressed endo-β-glucanase was characterized,and the results showed that the optimal pH is 4.5 and the optimal temperature is 45℃.The pH stability of the enzyme was 4.0-6.0,which was related to the type of buffer solution.Al^（3＋） had activation on the enzyme,but Mn^（2＋） and Cu^（2＋） inhibited the enzyme activity.The substrate specificity on carboxylmethyl cellulose sodium salt（CMC-Na）was strong.Pepsin had an inhibiting effect on the enzyme.