表达条件对金属激活酶NAOase离子依赖的活性分析

N-乙酰鸟氨酸脱酰基酶为一种新型手性拆分酶制剂,酶活性依赖于Mg2＋、Mn2＋、Zn2＋及Co2＋ 中的某种金属离子。以高表达NAOase的重组菌DH10B/argE-pHsh为研究对象,考察不同培养条件下Mg2＋、Mn2＋、Zn2＋及Co2＋ 4种离子对重组菌的生长、酶的表达活性及表达量的影响。结果发现：同种离子在不同条件下对重组菌的生长影响不大,但对酶活性影响显著。4种离子在合适浓度时皆能提高酶活性,促进强度从高到低依次为Mn2＋、Mg2＋、Co2＋和Zn2＋。在TB培养基中,Mn2＋为15 mmol/L时：NAOase比酶活达到1 272.7 U/mL,是未添加时的4.67倍,激活作用显著高于其他离子。SDS-PAGE电泳实验表明4种离子的蛋白表达量基本相同。

Activity analysis of expression conditions on ion dependent of metal activated enzyme NAOase

As a novel chiral separator of enzyme preparations, the activity of acetylornihine deacetylase depended on some of Mg2＋ , Mn2＋ , Zn2＋ and Co2＋ ions. Recombined DHlOB/argE-pHsh of high expression NAOase was investigated. The metal ions were chosen to probe their effects on the growth of recombinant bacteria and enzyme expression activity under different culture conditions. The result was that under different conditions the same ions had little effect on the growth of recombinant bacteria, but had a significant effect on the enzyme activities when it had appropriate concentration. All four ions enhanced the activity of enzyme, and in the order of Mg2 ＋ , Mn2 ＋ , Zn2 ＋ , and Co2 ＋ from high to low. When the TB medium contained 15 mmol/L of Mn2＋ , activity of the enzyme reached 1 272. 7 U/mL. It was 4. 67 times higher than that of without Mn2 ＋ in TB medium. Additionally, the effect of activation was significantly better than that with other ions. SDS-PAGE showed that the amounts of protein expression of the four ions were similar.