IPTG, dioxane free, Molbio Grade

IPTG is commonly used in cloning procedures that require induction of β-galactosidase activity. It is used together with X-Gal (5-bromo-4-chloro-3-indolyl-ß-D-galactoside) or Bluo-Gal (5-Bromo-3-indolyl-beta-D-galactopyranoside) in blue-white selection of recombinant bacterial colonies that induce expression of the lac operon in Escherichia coli. Mode of operation:While IPTG binds to the lacI repressor it is altering the conformation of the lacl repressor, which prevents the repression of the β-galactosidase coding gene lacZ. Thus IPTG is an inducer of the lac operon in bacteria for detection of lac+ colonies. Dissolve in water to e.g. 200mg/mL, sterilise by filtration and store in aliquots at -20°C. For detection of transformants, use in final concentration of 0.1mM up to 1mM in LB-Medium.

Ready-to-use 100mM IPTG solution (Isopropyl-ß-D-thiogalactopyranoside) for molecular biology research. IPTG is commonly used in cloning procedures that require induction of β-galactosidase activity. It is used together with X-Gal (5-bromo-4-chloro-3-indolyl-ß-D-galactoside) or Bluo-Gal (5-Bromo-3-indolyl-beta-D-galactopyranoside) in blue-white selection of recombinant bacterial colonies that induce expression of the lac operon in Escherichia coli. While IPTG binds to the lacI repressor it is altering the conformation of the lacl repressor, which prevents the repression of the β-galactosidase coding gene lacZ. Thus IPTG is an inducer of the lac operon in bacteria for detection of lac+ colonies. Shipped as 10 x 1mL solution.

X-Gal (5-Brom-4-chlor-3-indolyl-β-D-galactopyranosid) is a chromogenic substrate for β-galactosidase. It produces a blue color that can easily be detected visually. X-Gal is used in the identification of lacZ + bacteria, especially for the detection of ß-galactosidase, which is expressed by the recombinant vectors. X-Gal is often used in conjunction with IPTG > (for the induction of the lac promoter (lac operon)), for the screening of blue colonies. It is also used for the screening of ß-galactosidase reporter gene activity in transfections of eukaryotic cells. X-Gal is a substrate of ß-galactosidase, which releases by cleavage of the substrate 5-bromo-4-chloro-3-indoxyl (X). The enzymatically cleaved indoxyl is oxidized to the insoluble indigo. As a stock solution, for example, a 20mg/mL X-Gal solution in dimethylformamide can be prepared. For the use in LB / Amp - plates this stock solution is to be diluted 1 : 1000 (final concentration 20μg/mL) or 1: 500 (final concentration 40μg/mL). The heated medium should thereby be cooled to about 50°C. The amount of X-Gal may be reduced if an X-Gal solution in DMF is sprayed to the agar plates (already with bacterial colonies!). X-Gal is the substrate of choice for blue-white selection of recombinant bacterial colonies with the lac+ genotype.

Rose-Gal, also known as Red-Gal or Salmon-Gal, (6-Chloro-3-indolyl-ß-D-galactopyranoside), is a is a beta-galactosidase substrate which produces a salmon pink colour. Rose-Gal (Red-Gal / Salmon-Gal) serves as an alternative to X-Gal > for the enzymatic detection of Lac+ beta-Galactosidase activity in bacterial colonies. In colorimetric assays, recombinants (white) can be distinguished from non-recombinants (salmon). In conjunction with X-Gluc >, Rose-Gal (Red-Gal, Salmon-Gal) can be used for the simultaneous detection of GUS and Lac + activity on the same plate.