Basic Kirkwood – Buff Theory of Solution Structure and Appropriate Application of Wyman Linkage Equation to Biochemical Phenomena

Abstract

Background: Researchers who have shown interest in the consequence of introducing dry biomolecules or a solution of it into cosolvents generally known as osmolyte, have applied many models for the elucidation of the scientific basis of the results obtained. The Kirkwood and Buff theory (KBT) or its reverse form has been the basis for the interpretation of the effect of the osmolyte. There seems to be no generally acceptable definition of terms in the basic KBT mathematical formalism. There is also error in stated equations describing solution structure and misapplication of Wyman linkage relation. Therefore, the objectives of this research are 1) to show how the equation of preferential interaction parameter is derived based on KBT, 2) to show the appropriate way in which Wyman linkage relation can be applied, 3) to apply biochemical approach (using generated data) to the equation of preferential interaction parameter (preferential interaction parameter is symbolised as ) for its calculation and calculation of parameters linked to KBT derived equations.
 Methods: The research is mainly theoretical and partly experimental. The experiment entails Bernfeld method of enzyme assay for the generation of data.
 Results and Discussion: The change in solvation preference upon the ethanol partial denaturation of the enzyme and the corresponding change in preferential interaction parameter were respectively positive and negative in sign. Unexpectedly ethanol was preferentially excluded from the enzyme.
 Conclusion: The equations of preferential interaction parameters were derived. The appropriate way is either by calculation or measurement of preferential interaction parameter. Therefore, or for the change, cannot be a constant (or slope) and an instrumentation–based measurable parameter at the same time. Based on Wyman linkage relation, purely biochemical thermodynamic parameter is linked to preferential interaction parameters which are therefore, thermodynamic parameters.

Theoretical Insight into Preferential Interaction Issues and Solution Structure, and Contentious Apparent Hydrated Molar Volume of Cosolute

“…Where µ ୧ stands for chemical potential of any solution components. The preceding equations are in the furtherance of the reason why Γ ଶ୧ cannot be a measureable quantity and a slope at the same time as previously reported [15]. According to Timasheff [9],…”

“…∆ܰ ଶଵ is a slope then, as posited elsewhere [15] a slope, such as (∂In‫ܭ‬ ∂Inܽ ଵ ⁄ ) ,,େ మ or (∂In‫ܭ‬ ∂Inܽ ଷ ⁄ ) ,,େ మ must not contain independent variable such as ‫ܥ‬ ଷ given that molar concentration of water, ‫ܥ‬ ଵ is constant at a given thermodynamic temperature.…”

“…Equation (10a) appears to be a slope against the backdrop of the fact that ∆Γ ଶଷ is also a measureable parameter. This issue has been raised and concluded in favour of the view that the parameter cannot be an instrument based measurable parameter and a slope at the same time [15]. Thus, Eq.…”

“…As explained elsewhere [15], another reason, why calculation of ∆Γ ଶ୧ may be more useful for the determination of parameters is obtainable from the following equations [9,14]. In their contributions, Shimizu [14] and Rösgen et al [3] attempted to relate preferential interaction parameters with Kirkwood -Buff integrals (KBI).…”

“…Equations (14) and (15) show that, the plot of measureable parameters versus either 1/C 3 or C 3 gives C 1 N 23 and N 21 /C 1 respectively as slope.…”