Title: X-gal
CAS Registry Number: 7240-90-6
CAS Name: 5-Bromo-4-chloro-1H-indol-3-yl b-D-galactopyranoside
Molecular Formula: C14H15BrClNO6
Molecular Weight: 408.63
Percent Composition: C 41.15%, H 3.70%, Br 19.55%, Cl 8.68%, N 3.43%, O 23.49%
Literature References: Chromogenic substrate of the lacZ gene product, b-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 b-galactosidase: B. Pearson et al., Lab. Invest. 12, 1249 (1963); Z. Lojda, Histochemie 23, 266 (1970). Protocol for blue-white a-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).
Properties: Amorphous solid from methanol, mp 237-239° (dec). [a]D24 -69° (c = 1.0 in 50% DMF). Sol in DMF, DMSO.
Melting point: mp 237-239° (dec)
Optical Rotation: [a]D24 -69° (c = 1.0 in 50% DMF)
Use: In histochemical staining, in blue-white selection of bacterial colonies with lacZ gene activity during cloning experiments.
Xibenolol Xibornol Ximoprofen Xipamide Xylazine

CAS number 7240-90-6 YesY
PubChem 65181
ChemSpider 58680 N
MeSH X-gal
Jmol-3D images Image 1
Molecular formula C14H15BrClNO6
Molar mass 408.629
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

X-gal (also abbreviated BCIG for 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside) is an organic compound consisting of galactose linked to a substituted indole. The compound was synthesized by Jerome Horwitz and collaborators in Detroit, MI, in 1964.[1] The formal chemical name is often shortened to less accurate but also less cumbersome phrases such as bromochloroindoxyl galactoside. The X from indoxyl may well be the source of the X in the X-gal contraction. X-gal is much used in molecular biology to test for the presence of an enzyme, β-galactosidase. It is also used to detect activity of this enzyme in histochemistry and bacteriology. X-gal is one of many indoxyl glycosides and esters that yield insoluble blue compounds similar to indigo as a result of enzyme-catalyzed hydrolysis.[2]