Binding parameters experimental evaluation

The preferential binding parameter F2 can be measured experimentally using various methods such as sedimentation [4], dialysis equilibrium [7], vapor pressure osmometry [14], etc. and has been determined for numerous systems [2-7,9-13,18-22]. It is of interest to use these experimental results for the evaluation of protein solubility. 

Eqs. (8)-(12) demonstrate that the experimental preferential binding parameter can be used to predict the protein solubility. Of course, in turn the experimental protein solubility can be used to evaluate the preferential binding parameter. 

Equations 3 and 5 allow one to calculate the Kirkwood-Buff integrals G12 and G23 using experimental data regarding the preferential binding parameters r2 and the partial molar volume of a protein at infinite dilution in a mixed solvent 49-50,52 jjjg Kirkwood—Buff integrals Gn and Go can be evaluated on the basis of the properties of protein-free mixed solvent water + cosolvent. It should be mentioned that recently the Kirkwood—Buff theory was used to analyze the effects of various cosolvents on the properties of aqueous protein solutions. " ... 

Experimentally, v are measured by varying [A] and data analysis is performed to evaluate two binding parameters, n and K, often via linear transformation such as the Klotz equation and the Scatchard equation (Table 10.1). 

Forty-eight of these parameters are adjustable and were evaluated by a least-squares analysis of 92 experimental binding energies. The average deviation between the experimental and calculated values was 0.2 eV. 

Another indirect approach to quantify biologic uncertainty is to measure the observed variability in human populations. Calabrese (1985) examined a number of parameters related to toxicokinetics (metabolism, binding of chemicals to protein and DNA, and activity levels of enzymes). In studies that included between 10 and 349 subjects, Calabrese concluded that generally 75-95% of the population fell within a range of 10-fold. However, the author s conclusion was based on the supposition that the 10-fold factor was to account for the total range of human variability as opposed to the range from an experimental no-observed-effect level to the most susceptible person. In a similar study, Hattis et al. (1987) evaluated toxicokinetic parameters in 101... 

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