enantiotopismi

Enantiotopismi refers to a phenomenon in chemistry where two enantiomers of a chiral molecule exhibit different biological activities or sensory properties. Enantiomers are stereoisomers that are non-superimposable mirror images of each other, much like a left and right hand. While they share the same chemical formula and connectivity of atoms, their three-dimensional arrangement differs.

The key to enantiotopismi lies in the interaction of these chiral molecules with other chiral entities in biological systems. Proteins, enzymes, and receptors within living organisms are themselves chiral. When an enantiomer encounters such a chiral receptor, the fit can be significantly different for each enantiomer. This difference in binding affinity or interaction can lead to distinct biological responses.

A classic example is the case of thalidomide. One enantiomer of thalidomide was an effective sedative and antiemetic, while the other enantiomer caused severe birth defects. This tragic instance highlighted the critical importance of considering enantiotopism in drug development.

Similarly, enantiotopismi is responsible for the different smells of enantiomers. The olfactory receptors in our noses are chiral, and they interact differently with the two mirror-image molecules, leading to the perception of distinct odors. For instance, the enantiomers of carvone smell like spearmint and caraway. Understanding enantiotopismi is crucial in pharmaceuticals, agrochemicals, and flavor and fragrance industries.