PROTEIN DESTABILIZATION AT LOW-TEMPERATURES

This chapter puts the phenomenon of low-temperature instability in its proper context and to indicate how its study might encourage new thinking about protein stability. In discussing the effects of low temperatures on proteins, a clear distinction must be drawn between cold per se and freezing, mainly because freezing is the removal of water and is, therefore, accompanied by dramatic increases in the concentrations of all water-soluble substances in the residual liquid phase. Low temperature in the absence of freezing exerts its influence on proteins mainly through changes in the physical properties of the aqueous solvent medium. The chapter is limited to the reversible stability-instability relationships induced by exposure to low temperatures. Parallels are drawn between direct observations at low temperatures and the inferred behavior, as calculated from extrapolated data for heat and/or chemical destabilization. For experimental data to be of any use for a classical thermodynamic analysis, studies must be performed on homogeneous systems and must pertain to conditions of reversibility. © 1995, Academic Press Inc.