Statistical-Mechanical Studies of the alpha right arrow over left arrow beta Transformation in Keratins: II. The Tension-Length Isotherms.

In attempting to understand the yield region of the alpha right arrow over left arrow beta transformation in keratins (Astbury and Woods, 1933), we recently proposed a statistical-mechanical model (David and Schor, 1965) which generalized the work done by others on the helix right arrow over left arrow random coil transformation (Zimm and Bragg, 1959; Gibbs and DiMarzio, 1959) (thermal denaturation) to the case of a polypeptide under external tension (Birstein, 1962). We wish now to report the comparison of the quantitative aspects of this model to the observed tension-length isotherms (in the yield region) of Cotswold wool.