X-Gal (5-Bromo-4-chloro-3-indolyl-β-D-galactopyranoside) | High-Purity β-Galactosidase Substrate
AuSaMicS Catalogue Number: ASE-906 | CAS: 7240-90-6
X-Gal is the industry standard chromogenic substrate for β-galactosidase activity detection. Used in blue-white screening protocols across molecular biology laboratories worldwide, X-Gal provides reliable, visual identification of successful cloning and gene expression events.
Technical Specifications
Chemical Properties:
- Molecular Formula: C₁₄H₁₅BrClNO₆
- Molecular Weight: 408.63 g/mol
- Appearance: White to off-white crystalline powder
- Solubility: DMSO, DMF (limited water solubility)
- Storage: -20°C, protect from light
Quality Standards:
- Purity: ≥98% (HPLC)
- Functional activity: Verified with β-galactosidase reference
- Heavy metals: <10 ppm
- Water content: <2%
- Endotoxin: <0.1 EU/mg
Mechanism of Action
X-Gal serves as an artificial substrate for β-galactosidase enzyme. Upon cleavage, X-Gal releases galactose and 5-bromo-4-chloro-3-indoxyl, which spontaneously dimerizes and oxidizes to form an insoluble blue indigo compound. This reaction provides immediate visual detection of enzyme activity.
Reaction pathway: X-Gal + H₂O → Galactose + 5-bromo-4-chloro-3-indoxyl → Blue indigo dye
Primary Applications
Blue-White Screening
Standard protocol for recombinant clone identification:
- Insert foreign DNA into lacZα gene within cloning vector
- Transform competent E. coli containing lacZΔM15 complement
- Plate on medium containing X-Gal (20-40 μg/mL)
- Results: Blue colonies = empty vector; White colonies = successful recombinants
Reporter Gene Assays
- lacZ fusion constructs for gene expression studies
- Tissue-specific promoter analysis
- Protein localization studies
- Transcriptional regulation research
Industrial Applications
- Quality control in biotechnology manufacturing
- Bacterial identification in clinical diagnostics
- Environmental monitoring (E. coli detection)
- Fermentation process monitoring
Protocol Guidelines
Stock Solution Preparation:
- Dissolve X-Gal in DMF or DMSO at 20 mg/mL
- Store at -20°C in amber tubes (stable 12 months)
- Working concentration: 20-40 μg/mL in growth medium
Optimization Parameters:
- pH: 7.0-7.5 (optimal)
- Temperature: 37°C
- Incubation time: 2-8 hours for color development
- IPTG: 0.1-1.0 mM (if using inducible systems)
Performance Validation
AuSaMicS X-Gal (ASE-906) undergoes comprehensive quality testing:
Functional Testing:
- Activity verification with standardized β-galactosidase preparations
- Blue-white screening efficiency >95% with control plasmids
- Consistent color development kinetics
Analytical Testing:
- HPLC purity analysis
- NMR spectral confirmation
- Heavy metal analysis (ICP-MS)
- Microbial contamination testing
Storage and Handling
Powder Storage:
- Temperature: -20°C
- Humidity: <5% RH
- Light protection: Essential
- Container: Tightly sealed, inert atmosphere
Solution Storage:
- DMF/DMSO stocks: -20°C, 12 months stability
- Aqueous solutions: Prepare fresh (maximum 24 hours at 4°C)
- Light protection required for all solutions
Troubleshooting Common Issues
High Background (Blue Color in Controls):
- Check X-Gal purity and storage conditions
- Verify competent cell quality (lacZΔM15 status)
- Ensure proper antibiotic selection
Poor Color Development:
- Confirm β-galactosidase activity in positive controls
- Check X-Gal concentration and freshness
- Verify incubation temperature and pH
Inconsistent Results:
- Use fresh X-Gal solutions
- Maintain consistent preparation protocols
- Check for bacterial contamination
Competitive Advantages of AuSaMicS X-Gal
Superior Quality Control:
- Stringent purity specifications (≥98% HPLC)
- Functional activity verification with every batch
- Comprehensive certificate of analysis provided
Reliable Performance:
- Consistent lot-to-lot reproducibility
- Optimized crystal structure for enhanced solubility
- Extended stability under proper storage conditions
Technical Support:
- Expert consultation on protocol optimization
- Troubleshooting assistance from experienced biochemists
- Custom packaging options for bulk applications
Regulatory Compliance
X-Gal (ASE-906) is manufactured according to:
- ISO 9001:2015 quality management standards
- Laboratory reagent grade specifications
- Australian chemical safety regulations
- International shipping compliance (UN3077)
Ordering Information
Available Packaging:
- 100 mg (research scale)
- 1 g (standard laboratory)
- 5 g (bulk applications)
- Custom packaging available on request
Lead Times:
- Standard orders: 3-5 business days
- Express delivery: Next day (major cities)
- International shipping: 5-10 business days
Technical Support:
- Phone: +61 412 520 598
- Email: support@ausamics.com.au
- Online: www.ausamics.com.au
Related Products
Enhance your blue-white screening protocols with complementary AuSaMicS products:
- IPTG (Isopropyl β-D-thiogalactopyranoside)
- Ampicillin sodium salt
- Competent E. coli cells (DH5α, TOP10)
- LB Agar plates (pre-made)
About AuSaMicS: Leading Australian manufacturer and supplier of microbiological culture media and biochemical reagents. Serving research institutions, biotechnology companies, and diagnostic laboratories across the Asia-Pacific region since 2022.
Quality Guarantee: All AuSaMicS products are backed by comprehensive quality testing and technical support. Contact our team for protocol assistance or custom formulations.
Orders and Inquiries: support@ausamics.com.au | +61 412 520 598 | www.ausamics.com.au
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