isopropyl beta-D-thiogalactopyranoside

DescriptionIPTG (also known as Isopropyl-β-D-Thiogalactopyranoside) is a molecular biology reagent that functions as an inducer of galactosidase activity by binding to and inhibiting the repressor. It is a molecular mimic of allolactose, a lactose metabolite that triggers transcription of the lac operon, and it is therefore used to induce protein expression where the gene is under the control of the lac operator. IPTG cannot be hydrolyzed or broken down by the E. coli therefore the concentration remains constant during cell replication. IPTG is often used at a final concentration ranging from 0.5-1.0 mM. X-Gal is often used with IPTG since it provides an easy visual method to monitor whether protein expression has occurred. X-Gal as the name implies contains a galactose group that once metabolized causes a bright blue color change.

UsesIsopropyl-β-D-thiogalactoside is used as a reagent in molecular biology. It is used as an effective β-galactosidase inducer of protein expression where the gene is under the control of the lac operator. It is used with 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside to identify the non-recombinant plasmid in cloning experiments by blue-white screen methodology.

General DescriptionInducer for β-galactosidase, an enzyme that promotes lactose utilization. Use in conjunction with X-Gal. Molecular Biology grade.Stock solutions:X-Gal: 20 mg/ml in DMFIPTG: 20 mg/ml in waterUse 4:1 (X-Gal:IPTG)Assay: ≥99%Dioxane: None detectedMelting point: 110-114°CSpecific rotation [a]25/D (1%, water): -34.0 to -29.0° Intended for laboratory and manufacturing use only. Not for drug, food, or household use.