COLL 37 |
| Stephanie R. Dungan1, Justin W. Shimek2, and Catherine M. Rohloff1. (1) Department of Chemical Engineering and Materials Science, University of California, Davis, Department of Food Science and Technology, One Shields Ave., Davis, CA 95616, (2) Department of Food Science and Technology, University of California, Davis, One Shields Ave., Davis, CA 95616 |
| The type of surfactant nanostructures that form in oil/water mixtures is largely determined by the size of the spontaneous curvature of the surfactant monolayer. We are interested in the ability of protein molecules to alter the phase behavior of surfactants, in part motivated by the desire to create biocompatible microemulsions. The water-soluble, globular protein alpha-lactalbumin substantially enhances water solubilization and droplet size within the dilute water-in-oil microemulsion region for the surfactant AOT, and promotes the formation of new aqueous assemblies of protein, surfactant and isooctane (o/w microemulsion droplets). Under conditions of acidic pH or intermediate ionic strength, new birefringent or gel phases (respectively) are created in the presence of protein. These changes are consistent with an influence of the protein on changing the spontaneous curvature of the AOT monolayer. Possible peripheral or intrinsic interaction mechanisms for these effects are discussed. To probe the nature of the protein-interfacial interaction, we have conducted circular dichroism and fluorescence studies with two variants of a-lactalbumin. When self-assembling with surfactant, the protein molecule adopts an expanded, more flexible molten globule conformation with increased secondary structure. |
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ACS Award in Colloid and Surface Chemistry Symposium Honoring Clay Radke
Division of Colloid and Surface Chemistry |