Isopropyl beta-D-thiogalactopyranoside solution

General description

Isopropyl thiogalactose (IPTG) is a sugar derivative widely used for the induction of the expression of recombinant proteins in E. coli. This expression system requires that the gene of interest is cloned in plasmids containing the Lac promoter. IPTG Ready Made is a 0.2 μm filter sterilized solution of 200 mM IPTG. This reagent remains liquid at its storage temperature (-20 °C), thus avoiding freeze-thaw cycles and providing a user-friendly solution.

Application

Isopropyl β-D-thiogalactopyranoside solution is:

• used as an inducer for the expression of single domain antibodies(sdAbs) in E coli and bioactive peptides
• used in its half-life and decay studies
• suitable for induction of recombinant protein expression in systems controlled by the lac repressor

Biochem/physiol Actions

Isopropyl β-D-thiogalactopyranoside binds to the lac repressor and releases the tetrameric repressor from the lac operator in an allosteric manner. This binding allows the transcription of genes in the lac operon, such as the gene coding for β--galactosidase. The β-galactosidase gene is transcribed and monosaccharides are the product. Since Isopropyl β-D-thiogalactopyranoside cannot be metabolized by E. coli its concentration remains constant. Therefore, it is not a variable in the experiment.

Principle

Isopropyl β-D-thiogalactopyranoside binds to the lac repressor and releases the tetrameric repressor from the lac operator in an allosteric manner. This binding allows the transcription of genes in the lac operon, such as the gene coding for β-galactosidase. The β-galactosidase gene is transcribed and monosaccharides are the product.