Myoglobin diffusion constant

Fig. 6.28 From bottom to top effective diffusion constant from NSE experiments, S(Q) deduced from RMS A fits, and DqH(Q)=D(Q)S(Q) with H(Q) the hydrodynamic factor. The left side corresponds to a myoglobin solution of concentration c=14.7 mM and the right side c=30 mM. Note the strong reduction of the value of D upon concentration increase. (Reprinted with permission from [332]. Copyright 2003 Elsevier)...

Figure 11. Relaxation, 4>(r), of the center of energy is plotted for wave packets propagated by the normal modes of cytochrome c hydrated by 400 water molecules (circles) and myoglobin (squares). Curve is a stretched exponential, Eq. (33), with p = 2v = 0.52, the value fit to the computed energy diffusion data for cytochrome c plotted in Fig. 10, and time constant, t — 11 ps.

In such cases the rate constant may be controlled either by diffusion or by chemical factors depending on the conditions. Evidence for the simultaneous roles of diffusion and activation control has also been found for some other reactions in highly viscous solvents, in that they show curved Arrhenius plots, indicating that the rate is controlled by diffusion at low temperatures where the viscosity is highest, but by chemical activation at ordinary temperatures. Examples include the reactions of CO with haemoglobin and myoglobin in aqueous glyerol [10,c,d]. Reactions of simple radicals such as H- and HO- with solvated electrons... 

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