Experimental conditions may affect reproducibility of the beta-galactosidase assay

FEMS Microbiol Lett. 1992 Dec 15;100(1-3):87-90. doi: 10.1111/j.1574-6968.1992.tb14024.x.


Several experimental conditions and parameters contributing to the determination of beta-galactosidase activity, as proposed in Miller's assay, were studied. Use of the absorbance correction factor and the nature and concentration of permeabilizing agents were taken into account as different experimental conditions. Reaction time, culture volume, and growth stage were investigated as equation parameters. From a quantitative point of view the results, in terms of Miller units, are markedly affected by variation in these conditions. Therefore, to ensure reproducibility it is advisable to use constant values for all the parameters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chloroform
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Evaluation Studies as Topic
  • Gene Expression
  • Lac Operon
  • Nitrophenylgalactosides
  • Plasmids
  • Sodium Dodecyl Sulfate
  • beta-Galactosidase / analysis*
  • beta-Galactosidase / genetics


  • 2-nitrophenylgalactoside
  • Nitrophenylgalactosides
  • Sodium Dodecyl Sulfate
  • Chloroform
  • beta-Galactosidase