Binding site distribution

Figure 31.9. Binding-Site Distributions. The E. coli genome contains only a single region that closely matches the sequence of the lac operator (shovm in blue). In contrast, 20 sites match the sequence of the pur operator (shown in red). Thus, the pur repressor regulates the expression of many more genes than does the lac repressor.

Lakshman S., Mills R., Patterson H., and Cronan C. (1993) Apparent differences in binding site distributions and aluminum(lll) complexation for three molecular weight fractions of a coniferous soil fulvic acid. Anal. Chim. Acta 282, 101-108. 

The variables f and are computed from four a values, as indicated in Equation (21). This technique appears to locate the K values of some simple ligand mixtures, but it does not properly recognize the discrete nature of those ligand mixtures. From the limited number of attempts this author has made to test this approach, the method always predicts the existence of rather broad distributions of binding sites, even when only a few diserete sites are present. Nevertheless, when a complex mixture of proton binding sites is present, the method may be useful for estimating the actual nature of the binding site distribution. 

Tamayo F, Casillas J, Martin-Esteban A. Highly selective fenuron-imprinted polymer with a homogeneous binding site distribution prepared by precipitation polymerisation and its application to the clean-up of fenuron in plant samples. Anal Chim Acta 2003 482 165-173. 

One consequence of the uniform binding site distribution and high capacity of these polymers is that they may be rather better suited to the preparation of chromatographic (HPLC) stationary phases than noncovalently imprinted materials. In fact this was the conclusion arrived at by Hwang and Lee [15], who compared the chromatographic performance of cholesterol-imprinted polymers prepared by the semi-covalent (carbonate spacer) method with noncovalent MIPs incorporating... 

In the elucidation of retention mechanisms, an advantage of using enantiomers as templates is that nonspecific binding, which affects both enantiomers equally, cancels out. Therefore the separation factor (a) uniquely reflects the contribution to binding from the enantioselectively imprinted sites. As an additional comparison the retention on the imprinted phase is compared with the retention on a nonimprinted reference phase. The efficiency of the separations is routinely characterized by estimating a number of theoretical plates (N), a resolution factor (R ) and a peak asymmetry factor (A ) [19]. These quantities are affected by the quality of the packing and mass transfer limitations, as well as of the amount and distribution of the binding sites. 

Drug Interactions During Distribution Displacement from Plasma Protein Binding Sites... 

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