English Abbreviation: IPTG Product Alias: Isopropyl β-D-Thiogalactoside General CAS: 367-93-1 Product Purity: Sigma ≥99%, Merck ≥98%, INALCO ≥99% Product Appearance: White or off-white powder; forms a clear, colorless solution when dissolved in water. Molecular Formula: C9H18O5S Molecular Weight: 238.30 Storage Temperature: Store at 2-8°C; after preparation, store at -20°C. Can be kept at room temperature for up to one month. Primary Function: Isopropyl β-D-thiogalactoside (IPTG) is a highly potent inducer that remains stable as it is not metabolized by bacteria, making it widely used in laboratories. IPTG acts as an inducer of β-galactosidase activity. Based on this property, when pUC series vector DNA (or other vector DNA carrying the lacZ gene) is transformed into lacZ-deficient host cells or transfected using M13 phage vector DNA, the addition of X-Gal and IPTG to the plate medium allows for easy identification of recombinant clones through the formation of white colonies (or plaques), owing to α-complementation of β-galactosidase. Additionally, it serves as an expression inducer for vectors with promoters such as lac or tac.