X-α-Glc (5-Bromo-4-chloro-3-indolyl-α-D-glucopyranoside)

X-α-Glc (5-Bromo-4-chloro-3-indolyl-α-D-glucopyranoside, CAS 108789-36-2) is a chromogenic substrate specifically designed for the detection of α-glucosidase (EC 3.2.1.20) activity in microbiological and molecular biology applications, producing an insoluble intense blue-green precipitate (dibromo-dichloro-indigo dye) upon enzymatic hydrolysis that enables clear colony differentiation on agar plates. With molecular formula C14H15BrClNO6 (MW 408.63 g/mol), this compound features a β-haloindolyl aglycone α1-O-glycosidically linked to D-glucopyranose, remaining colorless and stable until cleaved by α-glucosidases from pathogens like Staphylococcus aureus, Bacillus species, and Enterobacter sakazakii (Cronobacter), where the liberated indoxyl spontaneously dimerizes and oxidizes to the highly colored indigo product visible without instrumentation. Incorporated into selective chromogenic media such as DFI agar for infant formula testing and general α-glucosidase screening, X-α-Glc provides superior contrast to fluorogenic substrates, permanent archival staining, and quantitative plaque enumeration, with applications in food safety (detection of Cronobacter in powdered milk), clinical microbiology (Staphylococcus differentiation), and functional screening of GH13 family enzymes in biofuel/biodegradation research. Its haloaromatic substitution enhances oxidation efficiency (>95% color yield) while minimizing spontaneous hydrolysis, distinguishing α-glucosidase-positive colonies (blue-green) from negatives within 24-48 hours at 37°C.

Appearance

• White to off-white fine crystalline powder.
• Forms blue-green insoluble precipitate post-hydrolysis.

Source

• Koenigs-Knorr synthesis: protected α-D-glucopyranosyl halide + 5-bromo-4-chloroindol-3-ol.
• Commercial microbiology grade (Sigma-Aldrich ≥98% HPLC, SRL 98%).

Molecular Weight and Structure

• Formula: C14H15BrClNO6; MW 408.63 g/mol.
• (2R,3R,4S,5S,6R)-2-[(5-bromo-4-chloro-1H-indol-3-yl)oxy]-6-(hydroxymethyl)oxane-3,4,5-triol.

Sugar Specificity

• Highly selective α-D-glucopyranoside for α-glucosidases (GH13 family).
• Negligible reactivity with β-glucosidases/α-galactosidases.

Biological Activity

• Chromogenic enzyme reporter; non-toxic to bacteria.
• Detects α-glucosidase activity via >1000-fold color intensification.

Purity and Microbial Contamination

• ≥98% (HPLC/TLC); molecular biology grade.
• Synthetic reagent; non-sterile.

Identity and Quality Control

• [α]D +105° to +110° (c=1, DMF:H2O 1:1); mp >200°C.
• Hydrolysis yields characteristic blue-green indigo (λmax ~610 nm).

Shelf Life and Storage

• Stable >3 years at -20°C desiccated.
• DMF/DMSO solutions stable months at -20°C.

Applications

• Chromogenic media for Staphylococcus, Bacillus, Cronobacter detection.
• α-Glucosidase enzyme screening, food safety testing.

Key Characteristics

• Eye-readable blue-green colonies; permanent archival stain.
• α-Specific; superior contrast to X-Gal/X-Glc.

Citation Links

• https://zellx.de/product/5-bromo-4-chloro-3-indolyl-%CE%B1-d-glucopyranoside-x-%CE%B1-glc/
• https://www.srlchem.com/product/details/25/74021/5-Bromo-4-Chloro-3-Indolyl-a-D-Glucopyranoside-X-a-Glc
• https://www.chemicalbook.com/ChemicalProductProperty_EN_CB8358680.htm
• https://www.sigmaaldrich.com/US/en/product/sigma/73837
• https://pubchem.ncbi.nlm.nih.gov/compound/2733916
• https://www.medchemexpress.eu/5-bromo-4-chloro-3-indolyl-%CE%B1-d-glucopyranoside
• https://www.sigmaaldrich.com/LT/en/product/sigma/73837
• https://pubchem.ncbi.nlm.nih.gov/compound/5-Bromo-4-chloroindol-3-yl-alpha-D-glucopyranoside
• https://www.inalcopharm.com/_download_files/10_12215032040.pdf
• https://www.navimro.com/p/K59762913/