Abstract
Wool keratin fibers were dissolved and separated into various heterogeneous protein compositions for the preparation of wool keratose film. A soluble fraction of keratose (s-keratose) could be obtained by oxidizing the wool keratin with performic acid, while $\alpha$, $\beta$, and ${\gamma}$-keratose were separated from an insoluble fraction by dissolving with $NH_40H$ solution. Also, new dissolving method of an insoluble keratose was investigated by using LiBr solution and the optimum conditions for a dissolution were found out The $\sigma$, $\tau$, and $\rho$-keratose could be separated from the insoluble keratose by dissolving in LiBr solution and dialyzing in a distilled water. The structural analysis of s, $\alpha$, and $\rho$-keratose solution and films was carried out by using circular dichroism, IR and $^{13}C$ NMR spectroscopy. The $\alpha$-helix content of s-keratose solution was higher than that ot $\alpha$-keratose. The random coil conformation was obtained in the solution of $\rho$-keratose, however the structural transformation occurred from random coil to $\beta$-conformation upon the film formation. As a result of X-ray diffraction analysis, the crystallinity of s-keratose film was somewhat higher than the others. It also confirmed that the content of $\alpha$-helix and $\beta$-sheet structure was higher for s-keratose and $\rho$-keratose film, respectively. This structural difference among three different keratose films related to the thermal degradation temperature as well as amino acid composition.
