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β-D-galactopyranoside, C19H21O9Na, MW 416.35, MDL Number MFCD03458481.
β-D-galactopyranoside, C19H21O9Na, MW 416.35, MDL Number MFCD03458481.
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. 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. From [http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=S7313%7CSIGMA&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&F=SPEC Sigma-Aldrich site].
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. 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. From [https://www.sigmaaldrich.com/US/en/product/sigma/s7313 Sigma-Aldrich site].
==S-Gal staining conditions==
==S-Gal staining conditions==
According to [http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=S7313%7CSIGMA&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&F=SPEC Sigma-Aldrich site]:
According to [https://www.sigmaaldrich.com/US/en/product/sigma/s7313 Sigma-Aldrich site]:
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 can be made by dissolving at 50 mg/mL in deionized water, sterile-filtering and storing at -20 °C.
https://bio.davidson.edu/courses/genomics/method/xgal.gif
Cleavage by beta-galactosidase yields a dihalogen-substituted indoxyl, 5-bromo-4-chloro-3-indoxyl:
Cleavage by beta-galactosidase yields a dihalogen-substituted indoxyl, 5-bromo-4-chloro-3-indoxyl:
Oxidation in the presence of an electron acceptor yields a relatively insoluble indigoid dye:
Oxidation in the presence of an electron acceptor yields a relatively insoluble indigoid dye:
=Oxidants used in histochemistry=
=Oxidants used in histochemistry=
Performic acid PMID: 1099403
Performic acid PMID: 1099403
Cepko, C., Ryder, E., Fekete, D.M., and Bruhn, S. Detection of B-galactosidase and alkaline phosphatease activities in tissue. Online: http://genepath.med.harvard.edu/~cepko/protocol/xgalplap-stain.htm. An excellent brief discussion of X-Gal histochemistry. Much of the material presented here was derived using their references.
Cepko, C., Ryder, E., Fekete, D.M., and Bruhn, S. Detection of B-galactosidase and alkaline phosphatease activities in tissue. Online (archive): https://web.archive.org/web/20160821210733/http://genepath.med.harvard.edu/~cepko/protocol/xgalplap-stain.htm. An excellent brief discussion of X-Gal histochemistry. Much of the material presented here was derived using their references.
=Studies in Enzyme Cytochemistry=
=Studies in Enzyme Cytochemistry=