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Study on interaction of alpha-amylase from Bacillus subtilis with cetyl trimethylammonium bromide
Abdol-Khalegh Bordbar1, Khodayar Omidiyan, Reza Hosseinzadeh
1Department of Chemistry, University of Isfahan, Hezarjarib Avenue, Isfahan 81746-73441, Iran. bordbar@sci.ui.ac.ir
Insights
Cetyl trimethylammonium bromide (CTAB) interacts with Bacillus subtilis alpha-amylase, showing highest binding affinity at 10(-3) M NaBr. Protein unfolding is observed between 3-5 M urea concentration.
Area of Science:
- Biochemistry
- Biophysical Chemistry
Background:
- Alpha-amylase is a crucial enzyme in carbohydrate metabolism.
- Cetyl trimethylammonium bromide (CTAB) is a cationic surfactant with known biological interactions.
Purpose of the Study:
- To investigate the binding interaction between CTAB and Bacillus subtilis alpha-amylase.
- To determine the influence of pH, ionic strength, and urea concentration on this interaction.
Main Methods:
- Utilized CTAB-membrane selective electrodes for accurate binding measurements.
- Analyzed binding isotherms using the Wyman binding potential concept.
- Experimentation conducted at 25°C under varying conditions.
Main Results:
- Highest binding affinity observed at 10⁻³ M sodium bromide (NaBr).
- Reduced binding affinity at pH 9.7 compared to pH 6.5, linked to protein self-aggregation.
- Predominant alpha-amylase unfolding occurred within 3-5 M urea concentration range.
Conclusions:
- CTAB exhibits significant binding with Bacillus subtilis alpha-amylase.
- Environmental factors like ionic strength, pH, and urea concentration modulate this interaction.
- Urea induces denaturation of alpha-amylase within a specific concentration range.
Abstract:
The interaction of cetyl trimethylammonium bromide (CTAB) with alpha-amylase from Bacillus subtilis was investigated at 25 degrees C and various experimental conditions, such as pH, ionic strength and urea concentration. The binding data were measured using CTAB-membrane selective electrodes as a simple, fast, cheap and accurate method. The obtained binding isotherms were analyzed using Wyman binding potential concept. The results represent the highest binding affinity at 10(-3) M of NaBr respect to other salt concentrations. The less binding affinity at pH 9.7 with respect to pH 6.5 is related to increasing of protein self aggregation with pH. The binding data analysis at various urea concentrations also shows that the predominate unfolding of alpha-amylase occurred in the urea concentration range of 3-5 M.
