摘要
本文采用邻苯二甲酸酐对漆酶进行化学修饰,考察修饰酶的稳定性及其降解多环芳烃蒽的反应特性。采用三硝基苯磺酸(TNBS)显色法测得漆酶的氨基修饰度为63.8%;以2,2’-连氮-双(3-乙基苯并噻唑-6-磺酸)(ABTS)为底物测定修饰漆酶的催化特性,修饰漆酶较天然漆酶具有更好的底物亲和性,其55°C下的酶活半衰期从192.5min延长至532.4min,其耐酸性也显著提高。圆二色性光谱和荧光光谱的表征结果显示修饰酶与天然漆酶具有相同的二级和三级结构;在30°C下,经过72h反应,修饰漆酶对蒽(anthracene)的降解率达到36%,较天然漆酶提高了近2倍。
Laccase is modified with phthalic anhydride in order to improve its stability against high temperature and acidic pH in this paper. The modification ratio of amino lysine groups of laccase is determined as 63.8% using TNBS method. It is shown that the modified laccase maintained the secondary and tertiary structure of its native counterpart but has a higher affinity to ABTS and an significantly improved thermal stability, as indicated by the extension of the half-life of enzyme activity at 55°C from 192.5 min to 532.4 min. The suitable pH range is also expended from pH5.9~7.8 to pH4.5~8.4. The degradation ratio of anthracene is increased by 2-fold, making the modified laccase promising for the removal of PAHs.
基金
国家自然科学基金(20336010)
关键词
生物化工
蒽的降解
化学修饰
漆酶
biochemical engineering
oxidation of anthracene
chemical modification
laccase
