中文摘要：

学习 Nattokinase 的 thermostability (subtilisin NAT， NK ) ，三两倍变异的 plasmids (pET-28a-NK < 潜水艇 class= “ a-plus-plus ” > G61C/S98C , pET-28a-NK < 潜水艇 class= “ a-plus-plus ” > T22C/S87C , pET-28a-NK < 潜水艇 class= “ a-plus-plus ” > S24C/S87C ) 被指导地点的 mutagenesis 构造。目标酶用 SDS 页被检测，二硫化物契约形成用西方的弄污的分析被检测。Thermostability 被 inactivation 的率在某些温度测试。结果证明那张二硫化物契约没在二半胱氨酸以内被形成，三两倍异种的 thermostability 没与野类型的 NK 相比被增加。NK 的 thermostability 表现在 Ca < 啜 class= “ a-plus-plus ” >2+ 比在 ethylenediaminetetraacetic 酸(EDTA ) 强壮。但是温度什么时候到达了 62 ? 慢桴摥椠 ? 瑀慥獲？

英文摘要：

To study the thermostability of Nattokinase（subtilisin NAT,NK）,three double mutant plasmids（pET-28a-NKG61C/S98C,pET-28a-NKT22C/S87C,pET-28a-NKS24C/S87C）were constructed by site-directed mutagenesis.Target enzymes were detected using SDS-PAGE and disulfide bond formation was detected using Western blotting analysis.Thermostability was tested by rates of inactivation at certain temperature.The results showed that disulfide bond was not formed within two cysteines and the thermostability of three double mutants was not increased compared with the wild-type NK.The thermostability of NK performed in Ca2＋was stronger than in ethylenediaminetetraacetic acid（EDTA）.But when the temperature reached 62℃,the enzymes rapidly denatured and inactivated even in the presence of Ca2＋.Although the thermostability of mutants was not increased,this study shows a tendency of improving thermostability of NK in protein engineering.