Receptor molecules blocks

Figure 11. Comparison of different assay types using a direct detection scheme were the receptors immobilized to the surface and the analyte is recognized at the surface (direct optical detection and using labelled systems), a competitive test scheme were labelled analyte molecules compete with the non-labelled sample, and thirdly a binding inhibition assay were analyte derivatives (ligand derivatives) are immobilized at the surface, in a preincubation phase the ligands block receptor molecules, non-blocked receptors go to the surface being either labelled or optically detected.

Non-competitive small molecule inhibitors that prevent conformational changes required to activate downstream signal transduction might also be therapeutically valuable. For example, if it does prove to be a critical phenomenon for receptor activation, blocking receptor dimerization with small molecules could be an effective approach for receptor antagonism. 

If a drug undergoes a covalent reaction with its receptor, the receptor molecules affected will be irreversibly blocked and thus altogether removed from the total receptor pool available for the interaction with the agonist. Thus, the agonist-receptor equilibrium now plays out in that reduced total pool. The number of occupied receptors will therefore be proportionally reduced (Figure 3.4). 

The cyclic structures at either end of the molecule block the receptor site from acetylcholine. 

Fig. 11.17 The dual function of pseudoprolines is demonstrated for the example of proline-rich peptides as ligands for Src homology domains (SH3). Wro building blocks induce the relevant PPM conformation of the ligand and allow in addition the modulation of affinity and specificity by tuning van der Waals contacts and hydrogen bonding interactions of the substituents Rat C2 of YPro to the receptor molecule [195].

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