The Cholesteric Phase in Polypeptide Solutions and Biological Structures

Abstract

Abstract In previous papers1–5 the remarkable properties of a liquid birefringent phase that separates from certain solutions of polypeptides in organic solvents when a limiting concentration is exceeded have been described. This phase, first observed by Elliott and Ambrose1 in solutions of poly-γ-benzyl-L-glutamate (PBLG) shows microscopically visible periodicities and a very high optical rotatory power.2 The order of magnitude of the optical rotatory power is comparable to that exhibited by the well-known cholesteric liquid crystals21,22 formed by esters and ethers of cholesterol, and which also show visible periodicities (the Grandjean layers) although these are smaller than the periodicties in the PBLG solutions.