Histochemical substrate for β-D-Glucuronidase (GUS) encoded by the gusA gene. The substrate is used as a qualitative histochemical marker of specific GUS expression in cells and tissue. X-GlcA is cleaved by GUS at the B1 glucuronic bond between glucuronic acid and the 5-Bromo-4-chloro-3-indolyl part of X-GlcA via hydrolysis. The cleavage of X-GlcA results in the precipitation of water insoluble blue dichloro-dibromo-indigo precipitate at the site of enzymatic cleavage.
Allow to warm to room temperature before using.