Glass transition and dynamics of molecules in partially crystallized aqueous solution of protein

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Three kinds of relaxation processes originated from uncrystallized water, ice, and hydrated protein were observed using broadband dielectric spectroscopyat temperatures between 113K and 300K in a frequency range of 1 mHz - 50 GHz for water mixtures with gelatin, bovine serum albumin (BSA), and lysozyme. The characteristic properties of the relaxation processes of uncrystallized water and hydrated protein were common to those observed in various kinds of non-crystallized aqueous solutions. Theinfluence of the melting of ice for the relaxation process of hydrated gelatin is larger than that of the hydrated BSA and lysozyme. The concentration dependences of the glass transition, melting, and crystallization temperatures in BSA- and lysozyme-water mixtures were clarified in entire concentration range. The glass transition and abrupt change of the relaxation time of the local chain motion of polymers caused by the condensation and plasticization induced by the melting and crystallization of solvents where observed in the mixtures of poly (vinyl acetate)-benzene and poly (ethyl acrylate)-p-xylene, and presence of the non-crystallized solvents were confirmed. It implies that the hydrogen-bond between water and polymer is not necessary for the presence of uncrystallized water at subzero temperatures.