Electrokinetic Aspects of Protein Chemistry

Exposure of a monomolecular layer of a labile, soluble protein to the high surface forces present at an air-water interface may produce changes which markedly modify its structure and properties. Although such investigations are of great importance in the analysis of protein structure, the conditions under which these denatured monolayers are formed may be quite different from those prevailing in biological systems. It seems important to emphasize that in a living organism, liquid-liquid and solid-liquid interfaces are in contact with various mixtures of dissolved proteins. Here the interfacial forces may be far lower (and thus less disruptive) and, in addition, amounts of protein greatly in excess of those needed to form monolayers are frequently present. Under such conditions, the initial surface-denatured film, if present, may become coated by one or more layers of nearly unaltered protein so that the behavior of the outermost layer next to the solution may assume...