北京棒杆菌天冬氨酸激酶突变体P184Q的酶学性质表征  

Characterization of Enzymatic Properties of Mutant P184Q of Aspartate Kinase from Corynebacterium pekinense

作　　者：方丽[1] 王锐楠 詹冬玲[1] 张芷睿 闵伟红[1] 

机构地区：[1]吉林农业大学食品科学与工程学院,长春130118

出　　处：《吉林大学学报（理学版）》2017年第6期1614-1620,共7页Journal of Jilin University:Science Edition

基　　金：国家高技术研究发展计划"863"项目基金(批准号:2013AA20112206-2);吉林省科技创新人才培育计划项目(批准号:20150519012JH)

摘　　要：通过分析谷氨酸棒杆菌天冬氨酸激酶(AK)的结构,筛选可能影响别构抑制剂结合的Pro184位点,对其进行饱和定点突变,成功筛选出突变菌株P184Q.酶学性质研究表明:突变体P184Q的V_(max)比野生型(WT)提高了3倍;n=1.39,低于WT的值(2.6),正协同性下降,同时Km值减小,对底物的亲和力增大;P184Q最适pH=6.5,最适反应温度为25℃,半衰期为2.8h;P184Q对金属离子和有机溶剂均表现出良好的抗性,解除抑制剂苏氨酸和甲硫氨酸、赖氨酸和甲硫氨酸、苏氨酸和赖氨酸、赖氨酸对酶活力的抑制作用.By analyzing the structure of aspartate kinase（AK）,we screened the Pro184 site that might affect the binding of allosteric inhibitors,and the mutant strain P184Q was successfully screened by saturation site-directed mutagenesis.The enzymatic properties show that the V_（max） of P184Q was 3 times higher than that of wide-type（WT）,n=1.39 indicating that the positive cooperativity of the substrate decreased,the Kmvalue decreased simultaneously,and the affinity of the substrate increased.The optimum pH of P184Q was 6.5.The optimum temperature of P184Q was 25 ℃.The half-life period was 2.8 h.Futhermore,P184Q how strong resistance to metal ions,organic solvent and inhibitors Thr＋Met,Lys＋Met,Thr＋Lys and Lys.

关 键 词：北京棒杆菌 天冬氨酸激酶 突变体 酶学性质 

分 类 号：Q814.9[生物学—生物工程]