5-Bromo-4-chloro-3-indolyl-ß-D-galactoside (X-Gal) research grade


X-gal is a well known histochemical substrate used to detect the ß-galactosidase enzyme (1, 2, 3, 4, 9, 10). Identification of lacf-colonies (8). X-gal is used to distinguish recombinant plasmids from parental vectors in cloning experiments using vectors containing the lacZ or lacZ [DMvP1](-)peptide gene (2, 3, 5). Upon hydrolysis, X-gal yields a localized, insoluble blue precipitate making it exceptionally useful in blotting, immunocytochemical, and ELISA assays. X-gal has been used for the detection of coliforms (E. coli) in municipal water supplies (6) and food products (7). X-gal is often used in conjunction with IPTG (Isopropyl-ß-D-thiogalactopyranoside, cat. no. 26600) which binds and inhibits the lac repressor thus inducing ß-galactosidase activity.Stock solution: 20 mg/ml in DMF. Store in aliquots at -20 °C in the dark. For detection of transformants, use in final concentration of 40 µg/ml.
DescriptionOrder No.PU Manuf. Prod. No. 
250 MG54402601-15243.06 
1 G54402591-15243.03 
5 G54402611-15243.07