Other Effects of Handedness

The shape of a molecule affects lots of things besides its smell. Our bodies, for example, can only use right-handed sugar; left-handed sugar is indigestible. Amino acids, the building blocks of proteins, are almost all left-handed--our bodies can't manufacture proteins out of the right-handed version. (The cell walls of bacteria are one exception; they contain right-handed amino acids.)

Mirror Molecules at the Drugstore

Ibuprofen bottle Many common drugs have right-handed and left-handed forms that behave very differently in your body.

Ibuprofen is one example of the "handed" drugs widely used in pain relievers. The left-handed version is about four times as strong as the right-handed twin. Enzymes in your body, however, can convert right-handed ibuprofen into the more potent left-handed form.

Another drug with two hands is the sedative Darvon. Its twin is used to make a cough medicine named Novrad--that's Darvon spelled backwards.

A Mirror Molecule and the FDA

FDA chemist
A chemist performs tests for the FDA. Courtesy of the Food and Drug Administration.
The U.S. Food and Drug Administration (FDA) has the responsibility for reviewing and approving requests by companies to market drugs in the United States. The agency is often called on to judge whether drugs have been adequately tested.

In 1960, hundreds of European babies were born deformed because their mothers had taken the sedative thalidomide for morning sickness. Many chemists think that the tragedy might have been averted if the thalidomide sold had been only one of the twin drugs instead of a mixture of both.

Who was Dr. Frances Kelsey?

Dr. Frances Kelsey was the medical officer at the FDA who dealt with attempts to distribute thalidomide in the United States. In spite of considerable pressure, she delayed the approval process until the harmful effects of thalidomide were identified.

In 1962, President Kennedy awarded a gold medal to Dr. Kelsey for her efforts. The Washington Post story read:

HEROINE OF FDA KEEPS BAD DRUG OFF MARKET. This is the story of how the skepticism and stubbornness of a government physician prevented what could have been an appalling American tragedy, the birth of hundreds, or indeed thousands, of armless and legless children.

Government officials in Europe, Japan, and the United States continue to study the best ways to regulate drugs that have handedness.

Where can I find out more about mirror mollecules?