Enhanced antifreeze effect of antifreeze protein on ice nucleation by electrolyte

Abstract

It is found that ice nucleation can be effectively suppressed by antifreeze protein at certain concentrations of electrolyte, because of the neutralization of the surface charge of the antifreeze protein molecules by the counterions. It follows from our ice crystallization experiment that the enhancement of antifreeze efficiency is based on the increase of the kink kinetics barrier of surface integration of water molecules and the disruption of the interfacial match between water and foreign particles by antifreeze protein molecules in the presence of electrolyte. This effect is attributed to the optimal packing of the antifreeze protein molecules on the surface of the ice nuclei as well as of the foreign particles when electrolyte ions are added. This work could provide a model for the study of the specific role of an electrolyte on the antifreeze efficiency of antifreeze proteins. The new understanding suggests another way to increase the antifreeze efficiency of the antifreeze proteins and provides us with a new insight into the antifreeze mechanism of antifreeze proteins on ice crystallization. © 2008 American Chemical Society.