α-天门冬氨酰二肽酶及其进化酶的FT-IR 研究

用分子定向进化技术，在酶活力和热稳定性双重选择压力下，筛选到了一体Keat／KM是天然酶47倍的进化酶。用FT－IR方法，测定了α－天门冬氨酰二须酶及其进化酶的酰胺I带图普，定量估算了天然酶和进化酶的各种二级结构含量。天然酶中，β折叠结构含量为28．5％，α螺旋结构含量为33％，这与园二色谱测量α螺旋结构为33％的结果有很好的一致，剩余的残基形成不同类型的转角和无规结构，其总含量为38．5％。在进化酶中，β折叠结构含量为26．8％，α螺旋结构含量为315，其它结构为不同类型的转角和无规结构，含量为42．2％。

FT-IR STUDIES OF α-ASPARTYL DIPEPTIDASE AND ITS EVOLUTIONAL ENZYME

Under double screen pressure of specific activity and thermo stablity, an evolved α-aspartyl dipeptidase, with 47 folds higher activity than its wild type ancestor, was obtained. By using FT-IR, the secondary structure of α-aspartyl dipeptidase and its evolutional enzyme were studied. It is found that α-helix structure is 31%,β-sheet content is 26.8% while turn and random coil component are 42.2% in the evolutional type of α-aspartyl dipeptidase .In the wild type enzyme, α-helix structure is 33%, β-sheet content is 28.5% and turn and random coil are 38.5%.These structure changes lead to arise the flexibility of evolutional type and adaptability to substrate.