A New Technique for the Spreading of Proteins and the “Spreading Number"

Abstract

THE ordinary volatile solvents employed for fatty substances cannot be used for the spreading of protein monolayers on the surface of water, since the majority of proteins are soluble only in water. Hughes and Rideal¹ have spread proteins directly from the dry crystal, the amount spread being determined with a microbalance. Gorter and Grendel² deliberately inject an aqueous solution of the protein on the surface without worrying about the possible disappearance of a part of it in the substrate. Fatty substances and the exceptional protein, gliadin, have been successfully spread from alcoholic solution, in spite of the fact that ethyl alcohol is soluble in water. It appears that in this case, owing to its large spreading pressure, the alcohol spreads very rapidly before it has time to diffuse into the substrate.