Physisorption of enzymatically active chymotrypsin on titania colloidal particles

[Display omitted] In this study we use a straightforward experimental method to probe the presence and activity of the proteolytic enzyme α-chymotrypsin adsorbed on titania colloidal particles. We show that the adsorption of α-chymotrypsin on the particles is irreversible and pH-dependent. At pH 8 t...

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Bibliographic Details
Published in:Journal of colloid and interface science 2015-10, Vol.455, p.236-244
Main Authors: Derr, Ludmilla, Dringen, Ralf, Treccani, Laura, Hildebrand, Nils, Ciacchi, Lucio Colombi, Rezwan, Kurosch
Format: Article
Language:English
Subjects:
Adsorption
Catalytic Domain
Chymotrypsin
Chymotrypsin - chemistry
Colloidal titania particles
Colloids
Enzymatic activity
Enzyme adsorption
Enzyme Assays
Enzymes, Immobilized - chemistry
Hydrogen-Ion Concentration
Hydrophobic and Hydrophilic Interactions
Kinetics
Nitrophenols - chemistry
Physisorption
TiO2
Titanium - chemistry
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Summary:[Display omitted] In this study we use a straightforward experimental method to probe the presence and activity of the proteolytic enzyme α-chymotrypsin adsorbed on titania colloidal particles. We show that the adsorption of α-chymotrypsin on the particles is irreversible and pH-dependent. At pH 8 the amount of adsorbed chymotrypsin is threefold higher compared to the adsorption at pH 5. However, we observe that the adsorption is accompanied by a substantial loss of enzymatic activity, and only around 6–9% of the initial enzyme activity is retained. A Michaelis–Menten kinetics analysis of both unbound and TiO2-bound chymotrypsin shows that the KM value is increased from ∼10μM for free chymotrypsin to ∼40μM for the particle bound enzyme. Such activity decrease could be related by the hindered accessibility of substrate to the active site of adsorbed chymotrypsin, or by adsorption-induced structural changes. Our simple experimental method does not require any complex technical equipment, can be applied to a broad range of hydrolytic enzymes and to various types of colloidal materials. Our approach allows an easy, fast and reliable determination of particle surface-bound enzyme activity and has high potential for development of future enzyme-based biotechnological and industrial processes.
ISSN:0021-9797
1095-7103
DOI:10.1016/j.jcis.2015.05.022