Asked in Chemistry
What is an enantimer?
September 13, 2011 2:02PM
Used in chemistry to distinguish between molecules that are mirror images of each other. This means that they have the same chemical formula and same connectivity (atoms are linked in the same way) but they still have different 3D shapes. A molecule will only have enantiomers IF it has a chiral center, an atom which has 4 different parts (for example -H, -CH3, -CH2CH3 and -CH2CH2CH3) connected to it.
Looking at your hands is a good way to understand how this works. First of all, both the left hand and the right hand have each four fingers, a thumb and a palm. But they are not identical, when you hold your hands in front of you with palms facing away, the thumbs are sticking out in opposite directions. Your hands are mirror images of each other. Built from the same parts and connected the same way, but the 3D shape is different. If you look at one of your hands in a mirror, the mirror image will look like if it is the other hand.
Enantiomers are especially important in biochemistry because the building blocks of our proteins, the aminoacids, exist as enantiomers (a "left" and "right" handed version). Nature is using the "left" type in all life, the "right" is not used. This means that "left" and "right" matters in the chemistry that keeps life going, and thus enantiomers can have very different effects on our bodies. While one enantiomer can act as a medicine, the other can be toxic.