10074. X-gal

Nomenclature

CAS number: 7240-90-6
5-Bromo-4-chloro-1H-indol-3-yl β-d-galactopyranoside.
C14H15BrClNO6; mol wt 408.63.
C 41.15%, H 3.70%, Br 19.55%, Cl 8.68%, N 3.43%, O 23.49%.

Description and references

Chromogenic substrate of the lacZ gene product, β-galactosidase; produces a rich blue color when cleaved by the enzyme. Prepn: J. P. Horwitz et al., J. Med. Chem. 7, 574 (1964). Colorimetric reaction in tissue to localize β-galactosidase: B. Pearson et al., Lab. Invest. 12, 1249 (1963); Z. Lojda, Histochemie 23, 266 (1970). Protocol for blue-white α-complementation screening: J. Sambrook et al., Molecular Cloning: A Laboratory Manual (Cold Spring Harbor, New York, 2nd ed., 1989) pp 1.7-1.9, 1.85-1.87. Optimization of detection of exogenous bacterial lacZ expression: D. J. Weiss et al., Hum. Gene Ther. 8, 1545 (1997); of fixative conditions in X-gal staining: W. Ma et al., J. Histochem. Cytochem. 50, 1421 (2002); of blue-white screening procedure: A. L. Sherwood, BioTechniques 34, 644 (2003).

Chemical structure

Properties

Amorphous solid from methanol, mp 237-239° (dec). [α]D24 69° (c = 1.0 in 50% DMF). Sol in DMF, DMSO.

Use

In histochemical staining, in blue-white selection of bacterial colonies with lacZ gene activity during cloning experiments.