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Updated: Jul 5, 2026

Measuring Enzymatic Stability by Isothermal Titration Calorimetry
Published on: March 26, 2019
Enzymatic activity of immobilized enzyme determined by isothermal titration calorimetry
Katja Henzler1, Björn Haupt, Matthias Ballauff
1Physikalische Chemie I, University of Bayreuth, D-95440 Bayreuth, Germany.
Abstract:
The activity of adsorbed beta-glucosidase onto spherical polyelectrolyte brushes (SPBs) is investigated by UV-Vis spectroscopy and isothermal titration calorimetry (ITC). By comparing the results of these two methods, we demonstrate that ITC is a precise method for the study of the activity of immobilized enzymes. The carrier particles used for immobilization here consist of a polystyrene core onto which poly(acrylic acid) chains are grafted. High amounts of enzyme can be immobilized in the brush layer at low ionic strength by the polyelectrolyte-mediated protein adsorption (PMPA). Analysis of the activity of beta-glucosidase was done in terms of Michaelis-Menten kinetics. Moreover, the enzymatic activity of immobilized enzyme is studied by ITC using cellobiose as substrate. All data show that ITC is a general method for the study of the activity of immobilized enzymes.
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