Simulation of protonic fluctuations in hydrated protein powders

Protons migrating on the surface of weakly hydrated protein powders provide a percolating mesoscopic system which exhibits charge fluctuations near room temperature. In this paper, we describe a simple numerical model where the statistical redistribution of protons on a space distribution of identical side chains lying on a spherical protein surface is varied by random ionization-recombination process to investigate the noise power spectrum of the fluctuating dipole moment, the ergodicity of this system, and the occurrence of localized or extended proton distributions. The case of lysozyme is considered to this end.