Iwamoto S, Kumagai H
Department of Applied Biological Chemistry, University of Tokyo, Japan.
Biosci Biotechnol Biochem. 1998 Jul;62(7):1381-7. doi: 10.1271/bbb.62.1381.
The behavior of the dielectric properties of gelatin in the frequency range from 10(3) Hz to 10(7) Hz was investigated and compared with that of the globule protein, bovine serum albumin (BSA), desalted gelatin and BSA being used. Dielectric relaxation was observed for both the gelatin and BSA solutions. The relaxation data were fitted well by the Cole-Cole equation; the Cole-Cole parameter (beta) and the relaxation time (tau) were obtained. For the BSA solutions, tau was proportional to the solution viscosity (eta) at 40 degrees C and 25 degrees C, and the values of beta at 40 degrees C were similar to those at 25 degrees C. For gelatin solution, tau was proportional to eta at 40 degrees C, but was not proportional to eta at 25 degrees C. In addition, the values of beta at 25 degrees C were smaller than those at 40 degrees C. These results indicate that the rotation of gelatin and/or polarization of submolecular groups in the coil state greatly contributed to the dielectric relaxation at 40 degrees C; on the other hand, the formation of cross-linking junctions consisting of helix structures would have affected the dielectric relaxation at 25 degrees C.
研究了明胶在10³Hz至10⁷Hz频率范围内的介电性能行为，并与球状蛋白牛血清白蛋白（BSA）进行了比较，使用的是脱盐明胶和BSA。在明胶和BSA溶液中均观察到介电弛豫现象。弛豫数据与Cole-Cole方程拟合良好；获得了Cole-Cole参数（β）和弛豫时间（τ）。对于BSA溶液，在40℃和25℃时，τ与溶液粘度（η）成正比，且40℃时的β值与25℃时的相似。对于明胶溶液，在40℃时τ与η成正比，但在25℃时不成正比。此外，25℃时的β值小于40℃时的。这些结果表明，在40℃时，明胶的旋转和/或卷曲状态下亚分子基团的极化对介电弛豫有很大贡献；另一方面，由螺旋结构组成的交联连接的形成会影响25℃时的介电弛豫。
