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S9811 Sigma

S-Gal®

reagent for selection of recombinant bacterial clones

Synonym: 3,4-Cyclohexenoesculetin β-D-galactopyranoside

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Properties

Related Categories Bacterial Culture Media, Core Bioreagents, Gene Reporter Substrates, General Reagents, Life Science Reagents for Cloning,
grade   for molecular biology
InChI Key   HDJJDRXZHJRVGA-DIKXUDHVSA-N
sterility   non-sterile
assay   ≥95% (HPLC)
form   powder
solubility   DMF: soluble50 mg/mL
suitability   suitable for β-galactosidase test
storage temp.   room temp

Description

Application

S-Gal is a patented autoclavable chromogenic substrate for β-galactosidase that is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype.

Suitable for use in selection of recombinant bacterial colonies with the lac+ phenotype. S-Gal® is autoclavable and can be added to bacterial broth containing agar prior to autoclaving.

Features and Benefits

• More intense color contrast than X-gal
• Excellent for use in automated colony counters
• Autoclavable for easiest use
• No need to make stock solutions

When S-Gal is cleaved by β-galactosidase, the resulting product will chelate ferric ion to create a black, insoluble precipitate. Lac+ colonies grown in the presence of S-Gal and ferric ion turn an intense black color, allowing for easy differentiation between lac+ and lac- colonies. S-Gal is autoclavable and can be added to your medium of choice prior to autoclaving. S-Gal is not light sensitive and does not require any protection from light sources.

General description

S-Gal® is an autoclavable, chromogenic substrate for β-galactosidase, used to determine the presence or absence of a cloned DNA insert in bacteria growing on agar plates. S-Gal® is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype.

Other Notes

Autoclavable, microwavable growth medium complete with S-Gal and IPTG.

The ferric or Fe3+ ion is required for color development and must be added to any S-Gal®
formulation. A medium prepared with S-Gal® is moderately dark due to the presence of ferric ammonium citrate. This darker background often provides enhanced contrast for automated colony counting or isolation.

Principle

When S-Gal® is cleaved by ß-galactosidase, the resulting product will chelate ferric ion to create a black, insoluble precipitate. Lac+ colonies grown in the presence of S-Gal® and ferric ion turn an intense black color, allowing for easy differentiation between lac+ and lac- colonies.

Reconstitution

Stock solutions of S-Gal® can be made by dissolving 50mg/ml in dimethyl formamide (DMF) and storing at -20C. Add S-Gal® (300 mg/L from stock solution ) and Ferric Ammonium Citrate (500mg/L) to agar media prior to autoclaving.

Legal Information

S-GAL is a registered trademark of Sigma-Aldrich Co. LLC

Price and Availability

Safety & Documentation

Safety Information

Symbol 
GHS07  GHS07
Signal word 
Warning
Hazard statements 
Precautionary statements 
Personal Protective Equipment 
RIDADR 
NONH for all modes of transport
WGK Germany 
3
Protocols & Articles

Articles

Competent Cells

Transformation is a process by which some bacteria take up foreign genetic material (naked DNA) from the environment. Once it enters the cytoplasm, the genetic material may be degraded by nucleases i...
Keywords: Antibiotics, Cloning, Detergents, Electrophoresis, Gel electrophoresis, Genetic, Molecular biology, Peptide synthesis, transformation

Introduction to Blue-White Screening

Blue-white screening is a rapid and efficient technique for the identification of recombinant bacteria. It relies on the activity of β-galactosidase, an enzyme occurring in E. coli, which cleaves lac...
Keywords: Antibiotics, Cloning, Culture media, Gene expression, Immunocytochemistry, Peptide synthesis, Polymerase chain reaction, Recombination, Sterilizations, transformation

Protocols

Transformation Protocols

From our library of Protocols, Sigma-Aldrich presents Transformation Protocols
Keywords: Antibiotics, Detergents, Electrophoresis, Gel electrophoresis, Mass spectrometry, Peptide synthesis, transformation

Peer-Reviewed Papers
15

References

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