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Published on: March 24, 2018
Imidazolium bromide-based ionic liquid assisted improved activity of trypsin in cationic reverse micelles
Sisir Debnath1, Dibyendu Das, Sounak Dutta
1Department of Biological Chemistry, Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032, India.
Langmuir : the ACS Journal of Surfaces and Colloids
|February 11, 2010
Summary
Imidazolium-based ionic liquids (ILs) enhance trypsin enzyme activity in CTAB reverse micelles. EMIMBr, an IL, boosted trypsin activity fourfold by improving water nucleophilicity, with minimal impact from more amphiphilic ILs.
Area of Science:
- Biocatalysis
- Enzyme activity enhancement
- Ionic liquids
Background:
- Trypsin, a key hydrolase, often requires specific environments for optimal activity.
- Cationic reverse micelles formed by CTAB offer a unique microenvironment for enzymes.
- Ionic liquids (ILs) are explored for their potential to modulate enzyme function.
Purpose of the Study:
- To investigate the effect of imidazolium-based ionic liquids (ILs) on the activity of trypsin solubilized in CTAB reverse micelles.
- To explore the structure-activity relationship of ILs with varying side-arm lengths in modulating enzyme performance.
- To understand the mechanism by which ILs enhance trypsin activity within the reverse micelle system.
Main Methods:
- Synthesis of imidazolium-based ILs with varying alkyl chain lengths.
- Assay of trypsin activity in CTAB reverse micelles with and without ILs.
- Dynamic light scattering (DLS) to analyze aggregate size in the presence of ILs.
- Circular dichroism (CD) spectroscopy to assess changes in trypsin secondary structure.
Main Results:
- Imidazolium-based ILs significantly enhanced trypsin activity, with improvements ranging from 30-300%.
- 1-ethyl-3-methyl imidazolium bromide (EMIMBr) demonstrated the highest enhancement, increasing trypsin activity approximately fourfold.
- ILs with greater amphiphilic character showed minimal impact, likely due to their interfacial localization.
- DLS and CD spectroscopy indicated a correlation between IL structure, aggregate properties, and enzyme activity, with EMIMBr maintaining enzyme structure closest to its native state.
Conclusions:
- Imidazolium-based ILs, particularly EMIMBr, are effective enhancers of trypsin activity in CTAB reverse micelles.
- The enhancement mechanism likely involves increased water nucleophilicity facilitated by the imidazolium moiety and bromide counterion.
- The localization and amphiphilic character of ILs play a crucial role in their effectiveness, influencing enzyme-IL interactions and overall activity.
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