脲酶水合特性的介电研究

Dielectric Studies of Urease as a Function of Hydration

本文报道了在低水合量下脲酶粉末样品的稳态电导率,及其在2×10^(-5)Hz和100kHz频率之间以及在1GHz频率上的介电特性。研究结果表明,蛋白质的α介电色散过程是由电极和样品界面附近的质子空间电荷所致。文中还报道了一个与脲酶结构的阻碍运动相关的介电色散过程,并指出多肽链骨架的极化运动明显地依赖于脲酶的水合。

The steady-state electrical conductivity, as will as the dielectric properties between 2×10^(-5)Hz and 100kHz, and at 1GHz, are reported for urease compressed powder samples of low hydration. The results show that the large, low frequency dielectric dispersion, known as α-dispersion, is due to the build-up of a space charge of protons at the sample-electrode interfaces. A smaller dispersion, appearing at higher frequencies, is concluded to be associated with hindered motions of the peptide residues in the molecular structure of urease. The extent of these polypeptide backbone motions is shown to be strongly dependent on the extent of enzyme hydration.