Transition binding affinity

Micellization is a second-order or continuous type phase transition. Therefore, one observes continuous changes over the course of micelle fonnation. Many experimental teclmiques are particularly well suited for examining properties of micelles and micellar solutions. Important micellar properties include micelle size and aggregation number, self-diffusion coefficient, molecular packing of surfactant in the micelle, extent of surfactant ionization and counterion binding affinity, micelle collision rates, and many others. 

One sure way of inhibiting metal catalysts is by the addition of metal cyanides. Cyanide has a strong binding affinity to most transition metals, the result usually being complete inactivation of the catalyst [73]. 

A third dataset was built in order to demonstrate that the descriptor is relevant for estimating binding affinity in a QSAR analysis. This last dataset contains 49 HIV-1 protease inhibitors, the 3D coordinates of which were those used by Pastor et al. (30). It has the four transition-state isosteres—hydroxy ethylene, hydroxyethylamine, statine, and a symmetrical diol. The X-ray structures of molecules numbered 1 and 3-34 have been reported (31), whereas molecules numbered 35-50 were modeled on the crystallographic structure of the complex of HIV-1 protease with L-689,502 solved at 2.25 A resolution (32). The binding affinity is expressed as pIC50 values. 

Houk KN, Leach AG, Kim SP, Zhang X. Binding affinities of host-guest, protein-ligand, and protein-transition-state complexes. Angew Chem Int Ed 2003 42 4872-4897. 

Often direct or indirect evidence suggests that peptides that are random coils in aqueous solution form helices when they bind to their receptors. In such cases it may be possible to enhance the affinity of the peptides for their receptors by introducing modifications that should make the coil-to-helix transition more favorable. By increasing the helical potential of a peptide, it should be possible to increase the binding affinity. 

In addition to the high affinity and selectivity, members of the CB[n] family can exhibit unusual dynamics of complex association and dissociation [9,21,28], We used the high binding affinities, high selectivities, and unusual dynamics to construct a system that undergoes well-defined transitions from free components, to one set of aggregates under kinetic control, to a second set of aggregates under thermodynamic control (Scheme 4.9). For example, when a solution of CB[6] and CB[7] is mixed... 

If some of the binding energy were used to introduce strain or distortion within the enzyme or substrate molecules, such that tighter binding of the transition state were achieved, then the binding affinity of the enzyme for the substrate would be reduced. 

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