知识与财富的链接
应用PCR技术,以大肠杆菌BL21（DE3）染色体DNA为模板,扩增得到S-腺苷蛋氨酸（SAM）合成酶基因。将所得基因连接至表达载体pET-22b（+）,利用T7强启动子进行转录,然后转化进E. coli BL21（DE3）表达菌株,构建出了具有高效表达SAM合成酶基因的基因工程菌。重组菌所表达的酶活为115U/g（以细胞干重计）。
The polymerase chain reaction (PCR) technique has been employed to amplify the S-adenosyl-L-methionine synthetase (SAMS) gene using the genomic DNA from E. coliBL21 as the template. The gene was cloned into the expression vector pET 22b (+) under the control of the strong T7-promoter. Therecombinant vector was transformed into the E. coli BL21（DE3）strain to construct the genetic engineered strain for producing high-yield SAMS. The measured enzyme activity was 115U/g.