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

摘要

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Fe2＋、Na2＋、K2＋、Ca2＋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 Fe2+,Na2+,K2+ and Ca2+. Broad stable pH and temperature range and tolerance to metal ions make this recombinant enzyme suitable in various applications.