Enantiomers

Definition

Enantiomers are a type of stereoisomer where two molecules are non-superimposable mirror images of each other. They have identical physical properties but differ in the direction they rotate plane-polarized light and their interactions with other chiral molecules.

5 Must Know Facts For Your Next Test

1. Enantiomers are crucial in biochemistry as many biological molecules, such as amino acids and sugars, exist in enantiomeric forms.
2. They can have drastically different effects in biological systems; for example, one enantiomer of a drug might be therapeutic while the other could be harmful.
3. Chirality is a key concept when discussing enantiomers — it refers to the geometric property where an object is not superimposable on its mirror image.
4. The D- and L- notation is commonly used to distinguish between enantiomers based on their optical activity.
5. Enzymes are often highly specific to one enantiomer over the other due to the three-dimensional shape of their active sites.

Review Questions

• What distinguishes enantiomers from other types of stereoisomers?
• How do enantiomers differ in their interactions with biological systems?
• Why is chirality important when discussing enantiomers?

Related terms

Stereoisomer: Molecules that have the same molecular formula and sequence of bonded atoms but differ in the three-dimensional orientations of their atoms.

Chirality:

A property of asymmetry important in several branches of science; an object or molecule is chiral if it cannot be superimposed on its mirror image.

Optical Activity: The ability of a chiral molecule to rotate plane-polarized light, measured using a polarimeter.