Dielectric Properties of Polypeptide Solutions. Measurement of the Dielectric Properties of the α-Helix by the Low Frequency Bridge Method

Abstract The work described above has produced the following conclusions. (1) A large electric dipole moment correspoinding to the α-helix described by Pauling, Corey and Branson is found in EDC and dioxane. (2) A linear relation between the electric dipole moment and the molecular weight in EDC suggests that the molecule is linear and not flexible. (3) The critical frequency of the orientation polarization was elucidated by using an equivalent ellipsoid model and the equation for the rotatory diffusion constant derived from Perrin’s equation. This fact will support the conclusion of Doty, Bradbury and Holtzer that the α-helix is fairly rigid in the solution. (4) In dioxane the α-helix can be found to be associated and to have a different distribution in molecular weight.