Denaturation rate

It may happen that the enzyme is denatured during a kinetic pressure experiment. If the denaturation rate is much faster than the reaction rate under study, it is clear that difficulties arise. A denaturation rate much slower than the reaction rate may be tolerated and easily corrected for by means of calibration measurements. When the denaturation rate and the reaction rate are comparable, some exact calculations should be carried through, showing the extent of the influence of the denaturation on the measured reaction rate. This can be done as follows ... 

Another possibility is that the denaturation of different forms of the enzyme proceeds with different rate constants (Greulich and Ludwig, 1977). As a simple example, let us consider the two forms free enzyme E and the substrate complex ES. Now, the denaturation rate of the total enzyme concentration [E]to, = [E] + [ES] is... 

Figure 15.13 compares calculated and experimental (dotted lines, [47]) band profiles of papain that is denatured on a C4-bonded reversed phase column. Papain does not denature in the sample solution (10 mM FI3PO4 at pH = 2.2), but in RPLC, it does and gives two peaks, the first one for the native form, the second one for the denatured form. The denaturation rate increases with increasing tern-... 

The kinetics of denaturation of peptide and protein drugs have not been extensively treated. Some studies on the temperature dependence of denaturation rates have been reported. A kinetic study of the denaturation of G actin in solution using DSC yielded linear Arrhenius plots, from which values for the activation energy and the frequency factor of 23 1 kJ/mol (55.2 kcal/mol) and 76.8 sA respectively, were obtained (Fig. 215).889 Linear... 

Examination of a small number of blood samples from patients with various diseases involving blood abnormalities have not shown any of these conditions to be associated with a fetal-type hemoglobin absorption spectrum with the exception of Cooley s anemia, a congenital disease which is common in certain Mediterranean countries. Liquori (1951) has found that blood from cases of this type of anemia has a slow alkali denaturation rate, comparable with that observed for fetal-type hemoglobin by Jonxis (1949), which enables it to be clearly distinguished from the normal adult type, which is denatured much more rapidly under the same conditions. 

The denaturation rate constant, k, can be expressed as a function of temperature and water content of the drying droplet as given by Equation 49.6 (Meerdink and Van tRiet, 1995) ... 

In order to establish the extent to which the native conformation of the protein is retained when in contact with functional silicones, proteins are entrapped within water-in-silicone oil emulsions and their biological activity assessed. The objective is to elucidate the nature of the interaction between the biological and synthetic polymers, the role of different polar groups on the silicones, the denaturation rate of the proteins in contact with the functionalised silicones, and the role of different polar groups on the silicone polymer. Through the use of modified silicones in conjunction with proteins at these water-oil interfaces, it may possible to increase the stability of not only the interface, but of the protein as well. The results presented, combined with the ability to entrap more than one protein in the emulsion droplets at time, offers a great potential for using these systems as delivery vehicles in oral vaccinations. 9 refs. 

For a given interaction energy, the faster the first step occurs, the higher will be the concentration of free denatured protein chains occurring as an intermediary, and hence the finer the gel network. Since the temperature coefiicients of denaturation rates are enormous, it is to be expected that a temperature increase would accelerate the first step far more than the second, leading to a finer structure, in agreement with the observed opacity and syneresis. 

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