重组葡激酶N端缺失突变体对纤溶酶原的激活作用  

Charateriztion of the Interaction between r Staphylokinase ΔN(r-SAK ΔN)and Plasminogen

作　　者：叶立文[1] 宋钢[1] 宋后燕[1] 

机构地区：[1]上海医科大学基础医学院分子遗传学研究室,上海200032

出　　处：《上海医科大学学报》2000年第1期9-12,共4页Journal of Fudan University(Medical Science)

基　　金：国家863 计划资助项目!860 - 103 - 13 - 01 - 02

摘　　要：目的　比较重组葡激酶（ＳＡＫ）及其Ｎ端缺失突变体（ΔＮＳＡＫ）对纤溶酶原（ＰＬＧ）激活作用的酶动力学常数，探讨ＳＡＫＮ端结构与功能的关系，以进一步改造ＳＡＫ分子。方法　采用酶反应动力学方法结合生物传感器测定ＳＡＫ、ΔＮＳＡＫ与ＰＬＧ、纤溶酶（ＰＬＭ）作用的动力学常数。结果　两者与ＰＬＭ形成的复合物催化ＰＬＧ的Ｋｍ值分别为６．２９、４．６μｍｏｌ／Ｌ，Ｋｃａｔ值分别为０．７２５ｓ－１、０．３１２ｓ－１；两者与ＰＬＧ的亲和系数分别为２．６４×１０８、１．０７×１０９；与ＰＬＭ的亲和系数分别为１．３２×１０９、３．６７×１０８。结论　ＳＡＫＮ端１８个氨基酸对ＳＡＫ·ＰＬＧ复合物及ＳＡＫ·ＰＬＭ酶催化活性中心的形成无明显影响。Purpose To study the characteristics of r SAK and r SAK Δ N reacting with plasminogen. Methods The K m and K cat value of r SAK·plamin and r-SAK Δ N·plasmin complexes for plasminogen were determined by kinetic methods.The affinity constants for binding of r SAK and r-SAK Δ N to plasminogen and plasmin were determined by real time biospecific interaction analysis. Results The K m value of r SAK· Results The K m value of r SAK·plasmin and r SAK Δ N·plasmin for plasminogen were 6.29 and 4.6 μmol/L ,respectively.The K cat value of r SAK·plasmin and r SAK Δ N·plasmin for plasminogen were 0.725 s -1 and 0.312 s -1 .The affinity constants of r SAK or r SAK Δ N with plasminogen were 2.64×10 8 and 1.07×10 9;the affinity constants of r SAK or r SAK Δ N with plasmin were 1.32×10 9 and 3.67×10 8. Conclusions The eighteen N terminal residuals were not required for the binding of SAK to plasminogen(plasmin) and the formation of enzymatic active center.

关 键 词：葡激酶 葡激酶缺失 突变体 纤溶酶原 SAK 

分 类 号：Q754[生物学—分子生物学] Q592.1