Helix–coil transition of poly(α,L-glutamic acid) at an interface: Correlation with static and dynamic membrane properties

When adsorbed from an aqueous dilute solution at high pH into the pores of an inert cellulose acetate filter, poly(α,L -glutamic acid) remains strongly anchored to the pore walls. The existence of the helix–coil transition for the adsorbed polypeptide in a certain pH range is evidenced by static and dynamic membrane properties displayed by the “activated” filter, such as excess cation uptake, membrane potential, and hyraulic permeability. In particular, the variations of the hydrodynamic thickeness present a sigmoidal shape characteristic of the helix–coil transition at the interface, a transition apparently less sharp than in solution.