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X-GAL is a chromogenic substrate for ß-Galactosidase used to differentiate recombinants from nonrecombinants in cloning experiments using vectors containing the lacZ or lacZ α-peptide gene.

Product Highlights

  • Perfect for cloning - gives an intense blue precipitate upon hydrolysis by β-galactosidase
  • Extremely pure - confirmed by TLC

Product Description

5-bromo-4-chloro-3-indolyl ß-D-galactopyranoside (X-GAL) is a chromogenic substrate for ß-Galactosidase that forms an intense blue precipitate.It can be used in molecular biology to detect the gal gene product, and also in microbiology where it is used to detect micro-organisms which have ß-Galactosidase activity (usually coliforms). It can be combined with the R-substrates to differentiate between two species of organisms on the same plate. X-GAL is soluble in N, N-dimethylformamide.

X-GAL is part of the Meridian Essentials range of products, which includes agaroses, buffers, PCR water and enhancers, antibiotic solutions, cloning reagents and protein digestion reagents.


  • Blue/White cloning systems
  • Immunoblotting
  • Immunocytochemical assays
  • Microbiology and cell culture media





X-GAL Powder

1 g

Storage & Stability

All components should be stored at -20°C upon receipt for optimum stability. Repeated freeze/thaw cycles should be avoided. Store protected from light.

When stored under the recommended conditions and handled correctly, full activity of the reagents is retained until the expiry date indicated on the outer box label.

Shipping conditions

On Dry Ice or Blue Ice.


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