X-Gal Powder | 5-Bromo-4-Chloro-3-indolyl β-D-galactopyranoside

X-Gal have been recognized to be a chromogenic substrate that used in the molecular biology and biochemistry fields for detecting enzyme β-galactosidase’s activity. They abbreviate X-Gal as 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside, which basically, it’s colorless until β-galactosidase hydrolyzing it, cleaving away galactose group and leaving a blue precipitate of 5-bromo-4-chloro-3-hydroxyindole behind. This blue color is often utilized as a visual marker symbolizing the presence of β-galactosidase activity in bacterial colonies otherwise in different biological sample.
As well as X-Gal is an timely indicator for coliforms and E. coli in culture media and it aids in the detection of Such organisms in municipal water supply and foods product. Moreover, this insoluble blue precipitate found helping in immunochemical, ELISA and in blotting methods.
Adding to it, X-Gal might be used together with an inducer IPTG, which binds and inhibits the lac, repressor thusly inducing β-galactosidase expression. X-gal therefore serves as substrate of choice for blue-white selection in recombinant bacterial colonies having lac+ genotype.