X-Gal (20mg/mL)

X-gal (5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside) is an organic compound consisting of galactose linked to a substituted indole. It is often used in molecular biology to test for the presence of an enzyme, β-galactosidase, in the place of its usual target, a β-galactoside. X-gal is colorless, but when cleaved by β-galactosidase, it yields a blue-colored product that can be used as a test for the presence of active β-galactosidase. This property allows bacterial β-galactosidase to be used as a reporter in various applications.

Applications

• Blue/white screening of bacterial colonies for cloning
• Detection of β-galactosidase activity in various assay systems