X-Gal
（5-Bromo-4-chloro-3-indolyl-s-D-galacto-pyranoside ）
Enzymatic Colorimetric Reagent, For GAL Detection
C14H15BrClNO6
M.W.: 408.63
Assay (HPLC): 99.4 %
Purity (TLC): >99%
Moisture: 0.4% (KF)
Solubility (2% Soln. in DMF): Clear and colorless
1H-NMR: Conforms to structure
Certified for use as a substrate of galactosidase in molecular biology.
White Powder
X-Gal is a chromogenic substrate of b-Galactosidase. It is used in conjunction with IPTG for detection of b-Galactosidase activity in bacterial colonies in a colorimetric assay to detect recombinants (white) from non-recombinants (blue). X-Gal is cleaved at the b 1-4 bond between galactose and the 5-Bromo-4-chloro-3-indolyl part of X-Gal by b-Glactosidase via hydrolysis.
The cleavage of X-Gal results in the production of a water insoluble blue dichloro-dibromo-indigo precipitate at the site of enzymatic cleavage.
In cloning strategies with vectors such as Lamda-11, M13mp18 and 19 and 19, pUC18 and 19, pUR222 the E.Coli lacZ gene is transformed to lac cells. After transformation the cells show b-Galactosidase activity in the presence of IPTG and X-Gal containing media. The insertion of a DNA fragment into the cloning sites of the lacZ gene results in the disruption of b-Galactosidase activity leading to the appearance of white colonies on X-Gal and IPTG containing media. Non recombinant cells produce a blue indigo dye on these media.
Stock conc.: 2% (w/v) by dissolving X-gal in dimethylformamide. Protect from light and store at -20℃.
Store at -20℃
