Allosteric modulation is an emerging paradigm for the development of new, targeted small molecule therapeutics. Allosteric modulators could offer a number of competitive advantages over traditional drugs including increased selectivity and greater control at the disease-mediating target.
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Most classical drugs bind to the disease-mediating target (an enzyme, protein, kinase, etc.) where the endogenous ligands bind (the natural molecular binding agent) - commonly referred to as the active, orthoscopic or orthosteric site.
The active sites that traditional drugs target tend to be highly conserved among protein superfamilies such as kinases and thus tend to exhibit a greater degree of off-target toxicities. Furthermore, this conservation makes it extremely difficult to develop drugs that are specific to receptor subtypes especially at physiologically active doses.
Allosteric sites on the other hand tend to be quite selective and modulators of these sites could exhibit fewer side effects compared to active site modulators binding the same target. Additionally, allosteric targeting usually provides a greater freedom to operate, as the intellectual property surrounding allosteric chemistry and allosteric sites on most targets is often unexploited.
Allosteric modulators may also more closely mimic normal physiological conditions as their activity occurs by enhancing or inhibiting the binding of an endogenous ligand, having no activity if that ligand is not bound to the active site. Because of this, allosteric modulators may offer a less disruptive way to modify biological functions, mimicking natural regulatory processes, leading to increased safety and reducing or eliminating side effects.