Properties and Applications:
(5-bromo-4-chloro-3-indolyl-beta-D-galactoside). beta galactosidase hydrolyses X-gal forming an indigo-type blue-green precipitate. Thus, bacteria which are positive for this enzyme produce blue colonies when grown in the presence of X-gal.

X-gal should be dissolved in Dimethylformamide at a concentration of 20mg/ml. The stock solution should at +4° C in the dark. Indicator plates are prepared by adding X-gal to a final concentration of 40mg/ml (a 1:500 dilution of the stock solution) after autoclaving the agar-containing media. Further applications of X-gal are the detection of B-Galactosidase in the fields of immunology and histochemistry.

Analytical Specifications:

• Recommended storage: frozen
• molecular weight: 408.64
• melting point: 230° C (d)