STOCKHOLM, Sweden (AP) _ Two Americans and a Japanese scientist shared the Nobel Prize in chemistry Wednesday for research dating back three decades on controlling chemical reactions _ work used for making medicines including a now-standard treatment for Parkinson's disease.
William S. Knowles of St. Louis and Ryoji Noyori of Nagoya University in Japan shared half of the $943,000 award. K. Barry Sharpless of the Scripps Research Institute in La Jolla, Calif., won the other half.
Their research deals with the fact that many molecules appear in two forms that are mirror images of each other, just like the left and right hands.
Cells generally respond correctly to only one of these forms, while the other form might be harmful. Drugs often use such mirror-image molecules, and the difference between the two forms can be a matter of life and death.
The Royal Swedish Academy of Sciences, which chooses the winners, singled out as an example the drug thalidomide, used by pregnant women in the 1960s. One form of the drug helped control nausea, while its opposite form caused birth defects.
Research by the Nobel winners has produced ways of making only the proper form of molecules, leading to antibiotics, anti-inflammatory drugs, ulcer treatments, heart medications _ even flavorings and sweeteners.
``The discovery can move frontiers of research forward in medicine, chemistry and biology,'' Per Ahlberg, a member of the academy's Nobel Committee, said at a news conference in Stockholm, Sweden. ``It's a breakthrough that started 33 years ago but the development is incremental.''
Knowles' breakthrough came in 1968, when he working for the Monsanto Co. in St. Louis. He found a way to make L-dopa, which is used to treat Parkinson's disease, without producing its mirror image.
``This was the first time this kind of a thing had been done,'' Knowles, 84, told The Associated Press on Wednesday. ``The field has since burgeoned and the other people who were with me in this thing have enlarged the field enormously. We started it and they pursued it.''
As for winning the Nobel prize, ``I never even conceived that this was possible _ especially after all these years,'' he said.
Noyori, 63, developed substances that encourage particular chemical reactions, making it easier for companies to produce large amounts of antibiotics and other drugs. He began his work in chemistry in the 1960s, when Japan was climbing back out of its postwar poverty.
``Looking back the time I started my research _ when this country was still poor _ I have come a very long way,'' Noyori said at a news conference. ``At that difficult time I discovered a bud and I have since kept nurturing it.''
Sharpless, 60, in 1980 did experiments that led to a method for creating beta-blockers, a widely used class of heart drugs.
His research has been described by many scientists as ``the most important discovery in the field of synthesis during the past few decades,'' the academy said.
The economics prize was to be announced later Wednesday.
The physics award went Tuesday to German scientist Wolfgang Ketterle and Americans Eric A. Cornell and Carl E. Wieman for creating a new state of matter that could lead to ways of producing faster electronics.
On Monday, Leland H. Hartwell of the United States and Britons Tim Hunt and Paul Nurse won the medicine prize for work on cell development that could lead to new cancer treatments.
The literature prize will be announced on Thursday and the peace prize on Friday.