Counter Effect of Sucrose on Ethanol-Induced Aggregation of Protein

The present paper is an attempt to study the mechanism of ethanol induced aggregation of chicken egg albumin and to stabilize the protein against ethanol induced aggregation. The protein aggregation was determined by monitoring the light scattering of protein aggregates spectrophotometrically. The protein undergoes certain structural changes in water- ethanol solution and the degree of aggregation was found to be linearly depending upon the concentration of alcohol used. The intrinsic fluorescence study showed a large blue shift in the λmax (16 nm) in the presence of 50% ethanol. The ANS fluorescence intensity was found to be gradually increasing with increasing concentration of ethanol. This indicates an increase in the hydrophobic cluster on the protein surface and as a result the hydrophobic interaction is appeared to be the major driving force for the aggregate formation. Addition of sucrose significantly reduced the ethanol-induced aggregation of chicken egg albumin. In presence of 50% sucrose the ethanol induced aggregation was reduced to 5%. The study reveals that addition of sucrose brings out changes in the solvent distribution and prevents the structural changes in protein which lead the aggregation.