Thermo Scientific X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galacto-pyranoside) is an inert chromogenic substrate for beta-galactosidase which hydrolyzes X-Gal into colorless galactose and 4-chloro-3-brom-indigo, forming an intense blue precipitate. Induction of the lacZ gene with IPTG leads to the hydrolysis of X-Gal and to the development of blue colonies (see Supporting data).
• Blue/white colony screening to distinguish recombinant (white) from non-recombinant (blue) colonies (see Reference 1) • Visualization of beta-galactosidase reporter gene expression in transfected eukaryotic cells • Detection of beta-galactosidase activity in immunological and histochemical procedures
Note • Preparation of a 20 mg/mL stock solution in dimethylformamide (DMF) or dimethylsulfoxide (DMSO) is recommended for X-Gal. DMF dissolves some plastic materials. The direct addition of DMF containing solution to plastic Petri dishes should be avoided. • DMF is toxic. Allow X-Gal solution containing dimethylformamide to completely dry before plating bacteria on agar plates.