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11:16
Hydrophobic Salt-modified Nafion for Enzyme Immobilization and Stabilization
Published on: July 11, 2012
Surface-induced changes in the structure and activity of enzymes physically immobilized at solid/liquid interfaces
1Department of Physical Chemistry and Colloid Science, Wageningen Agricultural University, POB 8038, 6700 EK, Wageningen, The Netherlands.
Biotechnology and Applied Biochemistry
|October 2, 1998
Summary
Enzyme adsorption on surfaces is influenced by surface properties like hydrophobicity. Adsorbed enzymes undergo structural changes, affecting their activity and stability, with less perturbation on less hydrophobic surfaces with grafted oligomers.
Area of Science:
- Biochemistry
- Surface Chemistry
- Enzyme Kinetics
Background:
- Enzyme adsorption onto solid surfaces is crucial for applications in biocatalysis and biosensing.
- Understanding how surface properties affect enzyme structure and function is key to optimizing these applications.
- Both alpha-chymotrypsin (proteolytic) and cutinase (lipolytic) were studied to assess generalizable principles.
Purpose of the Study:
- To investigate the impact of surface hydrophobicity and morphology on enzyme adsorption.
- To determine how surface-grafted, water-soluble oligomers influence enzyme adsorption.
- To characterize the structural and functional consequences of enzyme adsorption on solid surfaces.
Main Methods:
- Enzyme adsorption experiments using alpha-chymotrypsin and cutinase on surfaces with varying hydrophobicity and morphology.
- Circular Dichroism (CD) spectroscopy to assess protein secondary structure changes.
- Differential Scanning Calorimetry (DSC) to analyze thermal stability and conformational heterogeneity.
- Measurement of enzyme specific activities before and after adsorption.
Main Results:
- Enzyme adsorption affinity increased with surface hydrophobicity for both enzymes.
- Grafting water-soluble, flexible oligomers onto surfaces reduced enzyme adsorption.
- CD and DSC revealed significant structural perturbations in adsorbed enzymes, indicating conformational heterogeneity.
- Structural perturbation was minimized on less hydrophobic surfaces, those with oligomers, and at higher surface coverage.
- Adsorbed enzymes exhibited reduced specific activities, correlating with structural perturbation.
- Heat-induced inactivation and unfolding processes differed for adsorbed enzymes compared to solution.
Conclusions:
- Surface properties, particularly hydrophobicity and the presence of grafted oligomers, significantly modulate enzyme adsorption.
- Enzyme adsorption leads to structural perturbations and altered functional properties, including reduced activity and modified thermal stability.
- The findings provide insights into controlling enzyme behavior at interfaces for biotechnological applications.
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