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Stabilization of alpha-chymotrypsin by modification with beta-cyclodextrin derivatives
Michael Fernández1, María de Lourdes Villalonga, Alex Fragoso
1Enzyme Technology Group, Center for Biotechnological Studies, University of Matanzas, Matanzas, C.P. 44740, Cuba.
Biotechnology and Applied Biochemistry
|November 28, 2002
Summary
Chemically modifying bovine pancreatic alpha-chymotrypsin with beta-cyclodextrin derivatives enhanced its thermal stability and resistance to alkaline conditions while preserving enzymatic activity.
Area of Science:
- Biochemistry
- Enzymology
- Protein chemistry
Background:
- Bovine pancreatic alpha-chymotrypsin is a widely studied serine protease.
- Enzyme modification is a common strategy to improve protein stability and functionality.
- Beta-cyclodextrin derivatives are known for their complexation properties.
Purpose of the Study:
- To investigate the effects of chemical modification with specific beta-cyclodextrin derivatives on the stability of bovine pancreatic alpha-chymotrypsin.
- To assess the impact of modification on the enzyme's proteolytic and esterolytic activities.
- To explore the potential for enhanced thermostability and alkaline resistance.
Main Methods:
- Chemical modification of bovine pancreatic alpha-chymotrypsin using mono-6-formyl-beta-cyclodextrin and mono-6-succinyl-6-deoxy-beta-cyclodextrin.
- Quantification of incorporated oligosaccharide per mole of protein.
- Assays to determine proteolytic and esterolytic activity.
- Thermal stability studies including optimum temperature determination and resistance to thermal inactivation at elevated temperatures (45-55°C).
- Stability assessment at alkaline pH (pH 9.0).
Main Results:
- Modified enzymes incorporated approximately 3-5 moles of beta-cyclodextrin derivative per mole of protein.
- Full proteolytic and esterolytic activity was retained post-modification.
- Optimum temperature increased by 8°C, and thermostability enhanced by 4-6°C.
- Modified enzymes exhibited increased resistance to thermal inactivation between 45-55°C.
- A 7-fold increase in stability was observed upon incubation at pH 9.0.
Conclusions:
- Chemical modification of bovine pancreatic alpha-chymotrypsin with beta-cyclodextrin derivatives effectively enhances enzyme stability.
- The modifications lead to improved thermal and alkaline stability without compromising essential enzymatic functions.
- Supramolecular interactions likely contribute to the observed thermal stabilization effects.