Table of Contents
What are Epimers?
Epimers – Definitions: Epimers are molecules that have the same chemical composition but a different arrangement of atoms in the molecule. This results in different properties and can affect how the molecule behaves.
Epimers are two molecules that share the same molecular formula but have a different arrangement of the atoms in their molecules.
Epimers Examples
An epimer is a type of stereoisomer where the two molecules have the same chemical structure except for one stereocenter. The most common type of epimer is a C-2 epimer, where the two molecules differ at the C-2 carbon. For example, the two glucose molecules shown below are C-2 epimers.
- The vast majority of natural sugars are C-2 epimers. For example, the two most common forms of glucose, D-glucose and L-glucose, are C-2 epimers. D-glucose is the form of glucose found in most foods, while L-glucose is the form found in human blood.
- While C-2 epimers are the most common type of epimer, they are not the only type. For example, the two molecules shown below are C-3 epimers.
- C-3 epimers are not as common as C-2 epimers, but they can found in some natural sugars. For example, D-mannose and L-mannose are C-3 epimers. D-mannose found in some fruits and vegetables, while L-mannose is found in human urine.
- Epimers can also found at other carbons besides C-2 and C-3. For example, the two molecules shown below are C-4 epimers.
- C-4 epimers are even less common than C-3 epimers, but they can found in some natural sugars. For example, D-fructose and L-fructose are C-4 epimers. D-fructose found in many fruits, while L-fructose is found in honey.
Enantiomers and Diastereomers
There are two types of stereoisomers: enantiomers and diastereomers. Enantiomers are molecules that are mirror images of each other, while diastereomers are molecules that are not mirror images of each other. Enantiomers have the same chemical formula, but their atoms arranged differently and they rotate plane-polarized light in opposite directions. Diastereomers have different chemical formulas, and their atoms arranged differently but they do not rotate plane-polarized light in opposite directions.
