title: Alizarin-beta-D-galactoside: a new substrate for the detection of bacterial beta-galactosidase.
abstract: We describe the synthesis of a new substrate for the detection of bacterial beta-galactosidase. This substrate, alizarin-beta-D-galactoside, is readily hydrolysed to release alizarin which complexes with various metal ions to form brightly coloured chelates. A total of 367 strains of Gram-negative bacteria were examined for their ability to hydrolyse three chromogenic substrates: alizarin-beta-D-galactoside (Aliz-gal), cyclohexenoesculetin-beta-D-galactoside (CHE-gal) and 5-bromo-4-chloro-3-indolyl-beta-D-galactoside (X-gal). A total of 182 strains (49.6%) were found to hydrolyse at least one of the three substrates. All of these 182 strains (100%) hydrolysed Aliz-gal whereas only 170 (93.4%) and 173 (95.1%) hydrolysed CHE-gal and X-gal, respectively. We conclude that alizarin-beta-D-galactoside is a highly sensitive substrate for the demonstration of beta-galactosidase.
authors.affiliation: Department of Chemical & Life Sciences, University of Northumbria, Newcastle upon Tyne, UK.
authors.forename: A L
authors.initials: AL
authors.lastname: James
authors.forename: J D
authors.initials: JD
authors.lastname: Perry
authors.forename: K
authors.initials: K
authors.lastname: Chilvers
authors.forename: I S
authors.initials: IS
authors.lastname: Robson
authors.forename: L
authors.initials: L
authors.lastname: Armstrong
authors.forename: K E
authors.initials: KE
authors.lastname: Orr
mesh_terms: D000880:Anthraquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D002863:Chromogenic Compounds / Q000378:metabolism; D003470:Culture Media; D005697:Galactosides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000201:enzymology* / Q000254:growth & development; D001616:beta-Galactosidase / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; D002863:Chromogenic Compounds; D003470:Culture Media; D005697:Galactosides; C010078:alizarin; D001616:beta-Galactosidase