Enzymatic activity of immobilized enzyme determined by isothermal titration calorimetry

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• 作者：Katja Henzler ; Bjö ; rn Haupt ; Matthias Ballauff
• 关键词：Immobilization of enzymes ; Calorimetry ; Michaelis– ; Menten kinetics ; β ; -Glucosidase ; Adsorption
• 刊名：Analytical Biochemistry
• 出版年：2008
• 出版时间：15 July 2008
• 年：2008
• 卷：378
• 期：2
• 页码：184-189
• 全文大小：490 K

文摘

The activity of adsorbed β-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 β-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.