Lysozyme-water system, specific heat

Fig. 3. Specific heat of the lysozyme-water system from 0 to 1.0 weight fraction of protein. Least-squares analysis of the linear portion of the heat capacity function from 0 to 0.73 weight fraction of water gives = 1.483 0.009 J K g ...

The process of protein hydration is the stepwise addition of water to dry protein, until the hydration end point is reached. Heat capacity measurements (Yang and Rupley, 1979) serve as a framework on which to develop a picture. Figure 38 gives the dependence on hydration level of various time-average properties of lysozyme, over the hydration range 0-0.4 h, from the dry protein to slightly beyond the end point of the process. Curve d shows the dependence of the apparent specific heat on hydration level. It is directly related to the extent to which the thermal response of the lysozyme-water system deviates from ideal behavior. The nonideality of the system shows three discontinuities at 0.07, 0.25, and 0.38 h. 

Figure 12. (a) The specific heat of the systems lysozyme-water (squares), and DNA-water (triangles), (b) The local tetrahedral order parameter derivative. d2/dT, for lysozyme (squares) and DNA hydration water (triangles), (c) Diffusion constant of lysozyme (squares), and DNA (triangles) hydration water [40]. 

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