Question

Describe an approach to identify pharmacophores and auxophores.

Answer 1

The three-dimensional arrangement of atoms involved in the interaction between the receptor and the drug molecule is called the pharmacophore. The rest of the molecule is called the auxophore. To identify a pharmacophore certain atoms from the molecule by means of organic synthesis can be removed to study the biological activity of the new compound.

This approach results in three possibilities as follows:

a. If the removal of a group of atoms leads to a decrease in potency, it can be concluded that those atoms were likely to be part of the pharmacophore.

b. If the removal leads to an increase in potency, the conclusion would be that those atoms were not part of the pharmacophore but rather they constituted the auxophore but inhibited the binding of the pharmacophore.

c. If no change in potency is observed, then it can be concluded that those atoms were forming part of the auxophore and did not interfere with binding.

It should be noted that in carrying out these changes, not only the potency of the drug may be affected, but it is likely that a change in activity (which receptors are targeted) will be elicited as well.