Relation of dynamic changes in interfacial tension to protein destabilization upon emulsification.
The objective of this study was to link conformational changes of proteins at a water/methylene chloride interface to their destabilization upon emulsification. When 4 aqueous protein solutions (bovine serum albumin, beta-lactoglobulin, ovalbumin, or ribonuclease) were emulsified in methylene chloride, considerable proportions of all the proteins became water insoluble aggregates. There were also noticeable changes in the compositions of their water-soluble species. A series of water/methylene chloride interfacial reactions upon the proteins was considered a major cause of the phenomena observed. Based on this supposition, the interfacial tension was determined by a Krüss DVT-10 drop volume tensiometer under various experimental conditions. It substantiated that the interfacial tension was high enough to cause the adsorption of all the proteins. Under our experimental conditions, their presence in the aqueous phase resulted in reductions of the interfacial tension by the degrees of 8.5 - 17.1 mN m(-1). In addition, dynamic changes in the interfacial tension were monitored to compare relative rates at which the adsorbed proteins underwent conformational, structural rearrangements at the interface. Such information helped make a prediction about how easily proteins would denature and aggregate during emulsification. Our study indicated that emulsifying aqueous protein solutions in organic solvents should be handled with care, due to adverse interfacial effects.
College of Pharmacy, Catholic University of Daegu, Kyongsan City, Kyongbuk, Korea. hsah@cuth.cataegu.ac.kr
Hongkee
H
Sah
Soo-Kyoung
SK
Choi
Han-Gon
HG
Choi
Chul-Soon
CS
Yong
D000465:Algorithms; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D008752:Methylene Chloride; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D013499:Surface Properties; D013500:Surface Tension; D014867:Water / Q000737:chemistry
D004655:Emulsions; D011506:Proteins; D014867:Water; D008752:Methylene Chloride