纤溶酶SPFE-Ⅱ的纤溶机制和酶反应动力学研究  

Fibrinolytic Mechanism and Reaction Kinetics of a Fibrinolytic Enzyme SPFE-Ⅱ from Bacillus sp. nov. SK006

作　　者：沈国华[1] 华颖[1] 刘大群[1] 江波[2] 

机构地区：[1]浙江省农业科学院食品加工研究所,杭州310021 [2]江南大学食品科学与技术国家重点实验室,江苏无锡214122

出　　处：《中国食品学报》2010年第1期48-54,共7页Journal of Chinese Institute Of Food Science and Technology

基　　金：浙江省自然科学基金资助(No.Y3090482)

摘　　要：研究芽孢杆菌(Bacillus sp. nov.)SK006发酵产生的纤溶酶SPFE-Ⅱ的溶栓机理及酶促反应动力学参数。研究结果表明,SPFE-Ⅱ对纤维蛋白原的降解过程为先降解α链,之后是β链,而对γ链的降解最缓慢,这与人血纤溶酶对纤维蛋白的降解过程相同;SPFE-Ⅱ对纤维蛋白有直接降解作用,同时可激活纤溶酶原,从而间接降解纤维蛋白;SPFE-Ⅱ具有较强的酰胺水解活性,最适底物为N-Succ-Ala-Ala-Pro-Phe-pNA;采用Hanes-Woolf法求得作用最佳底物的特征常数:Km=0.51 mmol/L;kcat=154.25 s-1;kcat/Km=3.02×105 L/mol.s。A fibrinolytic enzyme （SPFE-II ） was produced from Bacillus sp. nov. SK006, isolated from fermented shrimp paste. Its fibrinolytic mechanism and enzymatic catalysis reaction kinetics parameter were studied in this paper, The results showed that SPFE-U was able to degrade fibrin clots in two ways： by forming active plasmin from plasminogen and by direct fibrinolysis. During the degradation process of fibrinogen, a-chains of fibrinogen were cleaved first, followed by slower release of the p-chains. F-chains were resistant to the enzyme digestion. SPIRE-Ⅱ had the highest affinity for N-Suee-Ala-Ala-Pro-Phe-pNA, which is a well-known substrate for subtilisin or ehymotrypsin. Km and Kcat for the synthetic of N-Succ-Ala-Ala-Pro-Phe-pNA were 0.51 mmol/L and 154.25s^-1 respectively obtained by Hanas-wooff method. In conclusion, SPFE-II has some potential for practical application as a source of functional foods and new therapeutic agents to treat thrombosis.

关 键 词：芽孢杆菌(Bacillus sp.nov.SK006) 纤溶酶SPFE-II 纤溶机理 反应动力学 

分 类 号：TQ920.1[轻工技术与工程—发酵工程]