IPTG (isopropyl-β-D-thiogalactopyranoside) is a commonly used inducer used to induce the expression of lactose operon (Lac) downstream genes and corresponding proteins in Escherichia coli [1]. When using pET, pLac or other expression systems controlled by Lac operators, IPTG as an inducer can effectively initiate large-scale expression of target genes [2]. The mechanism of action of IPTG is that its structure is similar to lactose and can bind to the lactose operon repressor protein (LacI), thereby preventing LacI from binding to Lac [3]. IPTG is not a harmless inducer, it exacerbates the toxicity of haloalkane substrates and causes significant damage to host cells [4].
References:
[1] Hansen L H , Knudsen S , Rensen S J .The Effect of the lacY Gene on the Induction of IPTG Inducible Promoters, Studied in Escherichia coli and Pseudomonas fluorescens[J].Current Microbiology, 1998, 36(6):341-7.
[2] Saïda F, Uzan M, Odaert B, et al. Expression of highly toxic genes in E. coli: special strategies and genetic tools[J]. Current Protein and Peptide Science, 2006, 7(1): 47-56.
[3] Marbach A , Bettenbrock K. lac operon induction in Escherichia coli: Systematic comparison of IPTG and TMG induction and influence of the transacetylase LacA[J].Journal of Biotechnology, 2012, 157(1):82-88.
[4]Exacerbation of substrate toxicity by IPTG in Escherichia coli BL21(DE3) carrying a synthetic metabolic pathway[J].Microbial Cell Factories, 2015, 14(1):201.
IPTG（异丙基-β-D-硫代半乳糖苷）是一种常用的诱导剂，用于诱导大肠杆菌中的乳糖操纵子（Lac）下游基因及对应蛋白的表达[1]。在使用pET、pLac或其他Lac运算子控制的表达系统时，IPTG作为诱导剂可以有效启动目标基因的大量表达[2]。IPTG的作用机制在于其结构与乳糖相似，能够结合到乳糖操纵子阻遏蛋白（LacI）上，从而使LacI无法结合到Lac[3]。IPTG不是一种无害的诱导剂，它加剧了卤代烷烃底物的毒性，并对宿主细胞造成明显的损害[4]。