U sing PCR m ethod, α-glucosidase gene consisted of 1587 nucleotide and encoded 501 am ino acids w as cloned from Therm ophilic bacilli and expressed in E .coliBL21 system . The subsequentcharacterization elucjdated thaα-glucosidase w as extracted fro BL21 bacteria w with a m obcular m ass of 66 kD and it had optin um activity at 90℃ and pH 7 .0 . Interestingly ,the relative activity w as 94% w hen incubated at 80℃ for 3 h,suggesting that it could m eet the industrial dem ands due to the properties of extrem e therm alactivity and stability .%应用PCR法从火山口嗜热菌中克隆出了α-葡萄糖苷酶基因,并将该基因导入大肠杆菌,获得了稳定表达的大肠杆菌菌株.同时对其表达产物进行了酶学性质分析.结果表明:该基因长1587 bp,编码501个氨基酸,为新α-葡萄糖苷酶同源基因,已将该序列在Genbank中登记;其表达产物经SDS-PAGE分析表明,相对分子质量约为66 kD;该α-葡萄糖苷酶的最适温度为90℃,最适pH值为7.0,在80℃放置3 h,酶活仍能达到94%以上.结果表明该酶具有优良的耐热性,将有广泛的工业应用前景.
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