CAS 7240-90-6 5-Bromo-4-Chloro-3-Indolyl-Beta-D-Galactoside X-GAL

5-Bromo-4-chloro-3-indolyl-beta-D-galactoside (X-Gal) is a commonly used substrate in molecular biology and biochemistry to detect the activity of the enzyme β-galactosidase. It is widely used in assays that involve the analysis of gene expression and protein localization.

Here are some key points about X-Gal:

1. Principle: X-Gal is a colorless substrate that, in the presence of β-galactosidase, is hydrolyzed to yield a blue product. This enzymatic reaction allows the detection of β-galactosidase activity in cells or tissues.

2. Application: X-Gal is often used in conjunction with the lacZ gene, which encodes β-galactosidase. In molecular biology, researchers commonly employ lacZ as a reporter gene to study gene expression, promoter activity, and protein localization. X-Gal staining can reveal the presence and activity of β-galactosidase, indicating the expression of the lacZ gene.

3. Color development: When X-Gal is hydrolyzed by β-galactosidase, it yields a blue product called 5,5'-dibromo-4,4'-dichloroindigo. This blue color is visually detectable and allows for qualitative analysis of β-galactosidase activity.

4. Substrate specificity: X-Gal is specifically cleaved by β-galactosidase and is not hydrolyzed by most other common enzymes, making it a specific and reliable substrate for detecting β-galactosidase activity.

5. Handling and storage: X-Gal is typically available as a powder that can be dissolved in a suitable solvent, such as dimethylformamide (DMF) or dimethyl sulfoxide (DMSO), to prepare a stock solution. It should be stored at -20°C in a dry and dark environment to maintain its stability.

6. Safety precautions: As with any chemical reagent, it is important to follow proper safety protocols when handling X-Gal. Avoid direct contact with the skin, eyes, or ingestion, and work in a well-ventilated area.

X-Gal has been widely used in various fields of research, including molecular biology, genetics, and developmental biology, as a valuable tool for visualizing and studying gene expression patterns.