Thermo Scientific X-Gluc (5-bromo-4-chloro-3-indolyl-beta-D-glucuronic acid, cyclohexylammonium salt) is a substrate for beta-glucuronidase (GUS) which is encoded by gusA, a widely used reporter gene. Glucuronidase cleaves X-Gluc to produce colorless glucuronic acid and an intense blue precipitate of chloro-bromoindigo (see the scheme below).
Glucuronidase cleaves X-Gluc
Preparation of a 0.1 M stock solution in dimethylformamide or dimethylsulfoxide is recommended.
J. Sambrook, D. W. Russell, Molecular Cloning: A Laboratory Manual (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, ed. 3, 16.42, 2001).
R. Jefferson, Assaying chimeric genes in plants: the GUS gene fusion system. Plant Mol Biol Rep. 5, 387-405 (1987).