Description_x000D_ General description_x000D_ 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._x000D_ Application_x000D_ 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._x000D_ 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._x000D_ Features and Benefits_x000D_ • More intense color contrast than X-gal_x000D_ • Excellent for use in automated colony counters_x000D_ • Autoclavable for easiest use_x000D_ • No need to make stock solutions_x000D_ 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._x000D_ Other Notes_x000D_ Autoclavable, microwavable growth medium complete with S-Gal and IPTG._x000D_ The ferric or Fe3+ ion is required for color development and must be added to any S-Gal®_x000D_ 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._x000D_ Principle_x000D_ 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._x000D_ Reconstitution_x000D_ 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._x000D_ Legal Information_x000D_ S-GAL is a registered trademark of Sigma-Aldrich Co. LLC