摘要
以产酸性淀粉酶菌株Bacillus sp.CN7的基因组DNA为模板,PCR扩增到α淀粉酶成熟肽基因,将该基因插入表达质粒pSE380中,构建重组质粒pSE380-cn7a。将重组质粒导入到Escherichia coli JM109中,IPTG诱导表达。重组酶经Sephacryl S300、Ni-NTA纯化后测定其酶学性质。重组酶CN7A的最适温度为65°C,最适pH为5.5?6.0,对可溶性淀粉的Km值为3.784g/L,最大反应速度为101.2mg/(L·min),该酶的热稳定性不依赖钙离子。
The α-amylase gene cn7a was amplified by PCR from Bacillus sp.CN7 genome DNA.The recombinant plasmid pSE380-cn7a was constructed by inserting gene cn7a into expression vector pSE380 and then transformed into Escherichia coli JM109.The purified amylase CN7A showed an optimal activity at pH 5.5？6.0 and 65°C,the Km value is 3.784 g/L taking soluble starch as substrate,and the maximum velocity was determined as 101.2 mg/（L·min）.Ca ion was not required for the thermal stability of CN7A.
出处
《微生物学通报》
CAS
CSCD
北大核心
2010年第10期1427-1431,共5页
Microbiology China
基金
国家科技支撑计划项目(No.2007BAD75B05)
国际科技合作项目(No.2008DFA30710)
