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Organic Solvent-Based Protein Precipitation for Robust Proteome Purification Ahead of Mass Spectrometry
Published on: February 7, 2022
Solubilizing water involved in protein extraction using reversed micelles
S Ichikawa1, M Imai, M Shimizu
1Department of Chemical Engineering, Division of Chemical and Biological Science, Faculty of Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo 184, Japan.
Biotechnology and Bioengineering
|January 5, 1992
Summary
This study reveals that the amphiphilic molecule AOT (di-2-ethylhexyl sodium sulfosuccinate) is crucial for protein extraction using reversed micelles. Higher AOT concentrations are needed with increased protein and ionic strength, with water accompanying extracted protein.
Area of Science:
- Biochemistry
- Physical Chemistry
- Separation Science
Background:
- Reversed micellar extraction is a key technique for isolating proteins.
- Understanding the role of surfactants and water is critical for optimizing protein recovery.
- Cytochrome c serves as a model protein for studying extraction dynamics.
Purpose of the Study:
- To investigate the relationship between solubilizing water and protein extraction efficiency using reversed micelles.
- To determine the critical concentration of di-2-ethylhexyl sodium sulfosuccinate (AOT) for complete protein extraction.
- To elucidate the influence of protein concentration, ionic strength, and pH on AOT requirements and water association.
Main Methods:
- Systematic investigation of protein (cytochrome c) extraction into an organic phase using AOT reversed micelles.
- Quantification of the minimal AOT concentration required for 100% protein extraction.
- Analysis of the molar ratios of solubilizing water to protein under varying conditions (protein concentration, ionic strength, pH).
Main Results:
- A critical AOT concentration was identified for 100% cytochrome c extraction, which increased with protein concentration.
- A constant molar ratio of solubilizing water to extracted protein (3500) was observed under specific ionic strength conditions.
- The amount of water accompanying extracted protein was quantified (2200 water molecules per protein molecule).
- Increased ionic strength necessitated higher AOT concentrations and more solubilizing water.
- pH was found to affect the minimal AOT concentration required for efficient protein extraction.
Conclusions:
- AOT acts as a crucial solubilizing agent, facilitating protein extraction by creating hydrophilic environments within reversed micelles.
- Water molecules are integral to the extraction process, accompanying proteins at a consistent molar ratio.
- Optimizing reversed micellar protein extraction requires careful consideration of AOT concentration, ionic strength, and pH.
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