E. coli beta-galactosidase is a 464 kD tetramer. Each unit of beta-galactosidase consists of five domains, the third of which is the active site. It is an essential enzyme in cells. Deficiencies of this enzyme can result in galactosialidosis or Morquio B syndrome. In E. coli, beta-galactosidase is produced by the activation of LacZ operon. Detection of LacZ expression has become routine to the point of detection of as few as 5 copies of beta-galactosidase per cell. This kit uses a red fluorogenic galactosidase substrate that can sensitively distinguish LacZ+ from LacZ- cells. The non-fluorescent substate generates a strongly fluorescent product upon reaction with galactosidase. It can be used either for detecting galactosidase conjugates in ELISA type assay systems or for monitoring LacZ gene expression in cells. Amplite® Fluorimetric Beta-Galactosidase Assay Kit comes with all the essential components with an optimized assay protocol. It can be used with a fluorescence microplate reader, a fluorescence microscope, or a flow cytometer. It might also be used for screening galactosidase inhibitors or inducers.