5-Bromo-4-chloro-3-indolyl-β-D-galactoside (X-Gal)
research grade
(X-Gal)
C14H15BrClNO6 • Mr 408.6 • CAS 7240-90-6
X-gal is a well known histochemical substrate used to detect the β-galactosidase enzyme.
Identification of lacf-colonies. X-gal is used to distinguish recombinant plasmids from parental
vectors in cloning experiments using vectors containing the lacZ or lacZ [DMvP1](-)peptide gene.
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 and food products. X-gal is often used in conjunction with IPTG (Isopropyl-β-D-
thiogalactopyranoside, cat. no. 26600) which binds and inhibits the lac repressor thus inducing β-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.
Assay (HPLC) | min. 99 % |
EINECS: 230-640-8 • WGK: 1 • HS: 29389090
Storage Temperature: +2 °C to +8 °C