

5-bromo-4-chloro-3-indoxyl-β-D-xylopyranoside by Molecular Depot is a chromogenic substrate for β-D-xylosidase that yields a blue precipitate on cleavage. The released indoxyl oxidises and dimerises in air to an insoluble indigo dye, so the colour forms as a precipitate where the enzyme is rather than diffusing into the medium. It is used to detect β-D-xylosidase on agar plates and in gels, in hemicellulase screening and microbial identification media and in histochemical staining. Each unit contains 25 mg. MBP supplies Molecular Depot carbohydrate reagents to research labs in the United States, Canada and worldwide.