Team:Cambridge/Protocols/beta-galactosidaseassay

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(Protocol)
(β-galactosidase Assay)
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===Theory===
===Theory===
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[[File:x-galreaction.jpg|right|250px|thumb|Chemical reaction by which x-gal can be detected]]
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===Protocol===
===Protocol===

Revision as of 10:07, 16 August 2012

β-galactosidase Assay

Theory

Chemical reaction by which x-gal can be detected

Protocol

  • Take suspension of cells grown up overnight and dilute 200 times in appropriate growth medium (for example LB broth for e.coli). If genetic construct can be selected for by an antibiotic, include this in the growth medium according to needs - this prevents loss of the plasmid during growth.
  • Now add the following to each of your eppindorf tubes:
ReagentVolume (µl)
X-Gal (10mg/ml)20
Substance of interest (e.g. Fluoride) (0.5 M)1 for each mM desired in final solution
Cell suspensionMake up to 500 μl
  • Leave tubes overnight in 37 °C incubator.
  • Tubes with most β-galactosidase activity will be most blue. This can be quantified using a spectrophotometer at wavelength 420 nm.