Knowles, 84, of St. Louis, Mo. and Noyori, 63, of Nagoya University in Japan shared half of the $943,000 award. Sharpless, 60, 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 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 research has led to ways of making only the proper form of these mirror-image molecules. The technology has led to methods of creating medicines like antibiotics, anti-inflammatory drugs and heart medications, the Royal Swedish Academy of Sciences said in its citation.
The science prizes have been awarded on the same day for decades, but the Royal Swedish Academy of Sciences decided to break with tradition after deciding the chemistry prize was often forgotten in the excitement of the earlier physics announcement.
The coveted prizes were established in the will of Alfred Nobel, the Swedish industrialist and inventor of dynamite and were first awarded in 1901.
Nobel gave little guidance other than to say the chemistry prize should go to those who "shall have conferred the greatest benefit on mankind" and "shall have made the most important chemical discovery or improvement."
The Nobel Memorial Prize in Economic Sciences was established separately in 1968 by the Swedish central bank, but it is grouped with the other awards.
The physics award went Tuesday to Americans Eric A. Cornell, 39, of the National Institute of Standards and Technology in Boulder, Colorado; Carl E. Wieman, 50, of the University of Colorado; and German scientist Wolfgang Ketterle, 43, of the Massachusetts Institute of Technology.
They were cited for creating a new state of matter called the Bose-Einstein condensate that could lead to ways to make ever tinier electronic circuits and more precise measurements.
Scientists say the condensates and atom lasers could lead to smaller and faster electronic circuits laid down by tiny beams of atoms.
The Nobels, which celebrate their centennial this year, started Monday with the naming of physiology or medicine prize winners American researcher Leland H. Hartwell and Britons Tim Hunt and Paul Nurse 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 in Oslo, Norway.
The prizes are always presented to the winners on Dec. 10, the anniversary of Nobel's death in 1896.
To mark the 100th anniversary of the prizes, all living lauretes have been invited to the ceremonies this year, with some 150 expected in Stockholm and 30 in Oslo.
Last year's chemistry prize went to Alan J. Heeger and Alan G. MacDiarmid of the United States and Hideki Shirakawa of Japan for the discovery that plastic conducts electricity and for the development of conductive polymers.
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