Amphipathic Character of Proteins and Certain Lyophile Colloids as Indicated by Absorption Spectra of Dyes

A characteristic change of spectral absorption of certain dyes as between water and organic solvents is shown to appear in aqueous solutions of gelatin or of the colloidal detergent, cetyl pyridinium chloride. This behavior is attributed to a bilateral character of lamellar micelles of such bodies, the elementary lamellae being polar and hydrophile on one side, non-polar and organophile on the reverse side. The possibility is indicated of diagnosing such amphipathic characteristics by comparative spectrophotometric measurements with suitable dyes.