Reaction, affinity average values

As we have seen the affinity of a reaction is at any instant a function of state of the system, and does not depend upon the conditions under which changes in the system occur. If we consider not the instantaneous value of the affinity but the average value in the course of a reaction, then this average will depend upon the conditions under which the reaction occurs e.g, whether at constant T and p, or T and V. In this book we shall employ the instantaneous values of the affinity, but to show the relationship between the present methods, and those introduced by Lewis and Randall we now proceed to express the average values of both heat of reaction and affinity in terms of the thermodynamic functions Z7, H, F and G. 

Equations (4.8) and (4.9) can also be written in terms of the average affinity and average heat of reaction. We start from the Gibbs-Helmholtz relation (4.33) and apply this to one state in which = 1, and another in which T and V have the same values but = 0 ... 

Antibody Characterization. Typical c-ELISA s for LLNL-Hept-2 using heptachlor as competitor (IS samples run over a 6-month interval) are presented in Figure 2. These data indicate that the average Iso tor heptachlor occured when 3.0 ng of analyte was added to the reaction. A standard deviation of 7% was observed causing the Iso values to range between 1.9 and 4.S ng/well. Similar variations were observed with other competitors. The LLNL-Hept-2 antibody used in the above experiments, and all subsequent experiments, was purified from ascites fluid by affinity chromatography on Sepharose Protein G (see methods section). 

This particular reaction has been chosen for the reason of its high value of standard chemical affinity for this reaction (j / = — 7.1 kcal/mole). As we noted above, due to this circumstance the system behavior can reveal the deviation from that prescribed by the classical Arrhenius mechanism. The conformational changes in malatdehydrogenase were tested by measuring the average life-time of intrinsic tryptophane fluorescence (ff). This parameter is known to be sensitive to the immediate surrounding of tryptophane residues. The chemical transformation of the substrate was detected from changes in the coenzyme redox state measured in terms of the sample optical density at 340 nm (NADH absorption maximum). 

The right-hand side of Eq. (6) is the O-atom residual valence for a polyhedron chain and correlates with the average pATa-value and the free energy of the acid-base reactions along a polyhedron chain, indicating the affinity of the constituent O-atoms for hydrogen bonds or O-H bonds [31]. 

---