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Updated: May 25, 2026

Measuring Lactase Enzymatic Activity in the Teaching Lab
Published on: August 6, 2018
Arrhenius plot for a reaction catalyzed by a single molecule of β-galactosidase
Douglas B Craig1, Linden N Chase
1Chemistry Department, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba, Canada R3B 2E9. d.craig@uwinnipeg.ca
Abstract:
The activity of a single enzyme molecule of Escherichia coli β-galactosidase was measured using a capillary electrophoresis continuous flow assay. As the enzyme molecule traversed the capillary the incubation temperature was increased from 27 to 37 °C, providing a continuous record of the change in rate with temperature. This data was used to develop a single enzyme molecule Arrhenius plot, from which the activation energy of the reaction was determined to be 31 kJ mol(-1).
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