乳糖作为诱导剂对重组目的蛋白表达的影响

将重组粒细胞-巨噬细胞集落刺激因子/白细胞介素3(GM-CSF/IL-3)融合蛋白表达菌BL21(DE3)(pFu)作为研究对象，对于以乳糖作为诱导剂时重组目的产物的诱导表达规律进行了深入的研究。分析比较了不同培养基中，不同生长阶段进行诱导对于产物表达的影响。对诱导所需的乳糖浓度、诱导持续时间长短等因素亦进行了研究。实验结果表明，在对诱导条件进行优化控制的前提下，利用乳糖作为诱导剂可以达到与IPTG类似的诱导效果。随后的研究中，将乳糖作为诱导剂应用于高密度发酵过程。这些研究结果为乳糖作为诱导剂最终应用于重组基因工程药物的工业化生产提供了有益的参考和借鉴。

The Influences of Lactose os an Inducer on the Expression of the Recombinant Proteins in Escherichia coli BL21(DE3)

The possibility of using lactose as an inducer to substitute the common inducer IPTG in the fermentation process of the recombinant microorganism was deeply investigated. The influences of culture conditions such as lactose concentration, growth medium composition, the point of induction and the duration of the induction phase on the expression of the recombinant protein were analyzed and studied in detail. In the following experiments,lactose was then used in the high cell density culture process of E. Coli BL21 (DE3)(pFu). The final cell density (OD600) was over 40. The expression level of recombinant protein was about 15% of the total cellular protein. Both the culture density and foreign protein expression level were lower than those induced by IPTG. However,because of the potential toxicity to human beings and the high cost of IPTG,the use of lactose might provide an alternative means of inducing foreign protein expression. This would be more attractive in industrial scale productions of recombinant proteins. The results confirmed that lactose could be used as an inducer in the fermentation process.