X-gal Stock Preparation
Updated 6/12/2015 08:29 PM
Introduction
Materials
- Consumables
- X-gal
- dimethylsulfoxide (DMSO)
- Disposables
- weigh dishes/paper
- pipette tips
- Equipment
- balance
- pipettor
Procedure
Table1
A A | B B | |
1 1 | Final Volume (mL)* | 10 |
2 2 | Concentration (mM)* | 50 |
Table3
A A | B B | |
1 1 | Component | Weight (g) |
2 2 | X-gal | 204.325 |
3 3 | DMSO | 10 |
Preparation
- Add calculated amount of X-gal to a light-tight container.
CRITICALContainer must be light-tight to avoid degradation of X-gal.
- Add the calculated amount of DMSO.
- Wait for full dissolution.
- OPTIONAL Distribute into smaller aliquots for storage.
This step will reduce the number of freeze-thaw cycles an individual sample will undergo.
- Store at -20°C, avoid light.
This protocol describes the preparation of a 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside (X-gal) stock solution at various concentrations.
Typically used in conjunction with IPTG for blue/white screening via the lac operon. A typical stock concentration of X-gal is 50mM (20mg/mL). To apply X-gal directly to the top of agar plates for blue/white screening, apply 40μL and wait to dry.