The dc protonic conductivity of powders of lysozyme was calculated from capacitance data measured for the frequency range 10 KHz to 10 MHz and for varied levels of hydration. Analysis of the hydration dependence of the conductivity close to the percolation threshold gave the value for the critical exponent t=1.290.05. This value is in close agreement with expectation from theory for a two-dimensional percolative process. These results support the idea that the threshold for hydration-induced protonic conduction (and, quite possibly, for enzymatic activity) corresponds to the formation of a percolation network of absorbed water molecules on the surface of this protein macromolecule. © 1988 The American Physical Society.
CRITICAL EXPONENTS OF PROTONIC PERCOLATION IN HYDRATED LYSOZYME POWDERS / G., Careri; Giansanti, Andrea; John, Rupley. - In: PHYSICAL REVIEW A, GENERAL PHYSICS. - ISSN 0556-2791. - STAMPA. - 37:7(1988), pp. 2703-2705. [10.1103/physreva.37.2703]
CRITICAL EXPONENTS OF PROTONIC PERCOLATION IN HYDRATED LYSOZYME POWDERS
GIANSANTI, Andrea;
1988
Abstract
The dc protonic conductivity of powders of lysozyme was calculated from capacitance data measured for the frequency range 10 KHz to 10 MHz and for varied levels of hydration. Analysis of the hydration dependence of the conductivity close to the percolation threshold gave the value for the critical exponent t=1.290.05. This value is in close agreement with expectation from theory for a two-dimensional percolative process. These results support the idea that the threshold for hydration-induced protonic conduction (and, quite possibly, for enzymatic activity) corresponds to the formation of a percolation network of absorbed water molecules on the surface of this protein macromolecule. © 1988 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
