Surface behavior of α-chymotrypsinogen A in aqueous solutions at 298.15 K

Abstract

In this work, a systematic study concerning the surface properties of α-chymotrypsinogen A in water and aqueous solutions of ethylene glycol, glycerol, meso-erythritol, D-sorbitol and myo-inositol at 298.15 K is developed to obtain a further insight of the stabilizing effect of polyols on the conformation of proteins.The results were used to establish if there is a general correlation between the surface tension of the solvent and the change in the denaturation temperature. Evolution of surface tension with time was used to obtain information on the adsorption process of the protein on the air-liquid interface in water and in the polyol solutions.The results show that there is a clear correlation between the surface tension of the solvent and the change in the denaturation temperature of the protein.The experimental adsorption isotherms of α-chymotrypsinogen in the air-liquid interface in water and in the presence of polyols were determined from surface tension measurements. Experimental data were fitted to semiempirical models that describe the adsorption process. They show that the adsorption process is well represented by a semi-empirical model that describes the process using three steps: a first step controlled by diffusion, a second step that presents a logarithmic behavior and represents the penetration rate of the protein at the air-water interface and a last step that also follows a logarithmic behavior and corresponds to the rate of rearrangement of the protein at the air-water interface.