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S7313 Sigma

S-Gal® sodium salt

reagent for selection of recombinant bacterial clones

Synonym: 3,4-Cyclohexeneoesculetin-B-D-galactopyranoside sodium salt

  • Empirical Formula (Hill Notation) C19H21O9Na

  • Molecular Weight 416.35

  •  MDL number MFCD03458481

  • Popular Documents:  Datasheet (PDF)  

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Properties

Related Categories Bacterial Culture Media, Broth / Media, Core Bioreagents, Gene Reporter Substrates, Life Science Reagents for Cloning,
grade   for molecular biology
sterility   non-sterile
assay   ≥95% (HPLC)
form   powder
IVD   not for in vitro diagnostic use
solubility   H2O: soluble100 mg/mL
suitability   suitable for β-galactosidase test
storage temp.   room temp

Description

Application

S-Gal, sodium salt is a patented water-soluble, 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® (sodium salt) is water-soluble, autoclavable and can be added to bacterial broth containing agar prior to autoclaving.

Caution

For black color development to occur, ferric ion must be present. Although we recommend ferric ammonium citrate (500 mg/L of media), other ferric compounds can be used to provide this requirement, depending upon your particular system.

Features and Benefits

• More intense color contrast than X-gal
• Water-soluble and autoclavable for easiest use
• Excellent for use in automated colony counters
• 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, Sodium salt is water soluble, eliminating the need for solvents such as dimethyl formamide. S-Gal is also 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® (sodium salt) is an autoclavable, water-soluble, 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

More water soluble version, soluble >50 mg/mL.

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.

Linkage

Ferric Ammonium Citrate (F5879), LB Agar (L2897), IPTG (Isopropyl β-D-thiogalactopyranoside, I6758), Ampicillin (A2804), Kanamycin (K0879), Chloramphenicol (C7795), Tetracycline (T8032)

Packaging

1, 5 g in poly bottle

100 mg in poly bottle

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

Add to agar media pre-autoclaving at a recommended concentration of 300 mg S-Gal/L of media, along with 500 mg/L Ferric Ammonium Citrate (F5879). Stock solutions of S-Gal can be made by dissolving at 50 mg/mL in deionized water, sterile-filtering and storing at -20 °C.

Stock solutions of S-Gal® (sodium salt) can be made by dissolving 50mg/ml in water, dimethyl formamide (DMF) or DMSO. Filter sterilize and store at -20C. Add S-gal® (300 mg/L from stock solution or powder) 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

RIDADR 
NONH for all modes of transport
WGK Germany 
3
Protocols & Articles

Articles

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

Peer-Reviewed Papers
15

References

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