(NEW YORK TIMES)
Henri Kagan and Kenso Soai were awarded the Nobel Prize in chemistry Wednesday for solving a long-standing mystery about mirror images in molecules. Their work has led to advances in the pharmaceutical industry and in scientists' quest to understand the molecular origins of life.
Some molecules, such as water and carbon dioxide, are so symmetrical that if you lined up their mirror images, they would match. However, chiral molecules - which include sugars, common medications and amino acids - are asymmetrical. Like our right and left hands, they look and act alike but if you lay one on top of the other, they don't quite match.
Kagan and Soai worked to understand these chiral molecules, and how chirality can change the result of chemical reactions. The Royal Swedish Academy of Sciences called their discoveries "decisive for chemists who design reactions for the manufacture of pharmaceuticals".
Kagan, 95, is French and a professor emeritus at Université Paris-Sud in France. He has been working on the issues of chirality since the 1960s.
Soai was born in 1950 in Hiroshima, Japan, and is a professor emeritus at the Tokyo University of Science. He established his research group at the university in 1981 and first performed the "Soai reaction" celebrated by this year's Nobel in 1995.
Some molecules, such as amino acids, can exist as two variants that are each other's mirror images. But the proteins in living organisms are made from only one of those mirror images. This property, called homochirality, is fundamental to life as we know it. And yet chemists long struggled to find reactions that would produce only one mirror molecule.
Kagan and Soai helped solve this conundrum, leading the way for scientists to choose molecules' chirality by manipulating the inputs of a chemical reaction.
Kagan took the "first decisive step in 1986", the Nobel Committee said, when he discovered a new way of manipulating chemical reactions that "allowed him to create a greater excess of one of the mirror images than had previously been thought possible".
Soai took the next step, designing "the first ever chemical reaction that had the potential to be homochiral" - which he finally succeeded in doing in 2003, the committee added.
Kagan and Soai's work on controlling the handedness of molecules has added another tool for chemists seeking to create new or better versions of drugs and other therapeutics.