Characteristics of protein-aqueous medium interactions measured by partition in aqueous Ficoll-Dextran biphasic system.

Partitioning of a number of proteins in the aqueous Ficoll-400-Dextran-70 biphasic system was studied at pH 7.4 under varied ionic compositions. The relative hydrophobicities of the proteins have been estimated, and the contributions of the interactions of the ionogenic and non-ionic groups of a protein with an aqueous environment to the total hydrophobicity of the protein have been evaluated. Some arguments in support of the biological significance of the effect of ionic composition on the relative hydrophobicity of biological macromolecules are given. Possible applications of the partition technique to protein research are discussed.