新型海洋源β-半乳糖苷酶在毕赤酵母中的表达与酶学性质

Expression and characterization of a novelmarine β-galactosidase in Pichia pastoris

从海洋环境β-半乳糖苷酶基因出发,采用毕赤酵母表达体系,构建产β-半乳糖苷酶的基因工程菌,并对重组酶酶学性质进行表征。结果发现:海洋源β-半乳糖苷酶具有优良的乳制品用酶特性,该重组酶的最适pH为7.0~8.0,最适温度为45℃,在50℃以下孵育1 h可保持55%以上的活力,能耐受Fe^(2+)、Na^(2+)、K^(2+)、Ca^(2+)等多种金属离子。宽广的pH、温度、金属离子稳定性,以及低温活性赋予该酶良好的乳制品用酶特性。

Using Pichia pastoris expression system, we constructed a recombinant P. pastoris strain producing marine β？galactosidase that was subsequently characterized. The recombinant enzyme had optimum pH between 7. 0 and 8. 0. Its optimum temperature was 45 ℃, and over 50% relative activity below 50 ℃.It was stabile in the presence of Fe^2＋,Na^2＋,K^2＋ and Ca^2＋. Broad stable pH and temperature range and tolerance to metal ions make this recombinant enzyme suitable in various applications.