WILLIAM STANDISH KNOWLES
WILLIAM Knowles, who was 84 and in retirement when he shared the Nobel prize in chemistry in 2001 for improving ways to manufacture drugs, including L-dopa for the treatment of Parkinson's disease, has died of complications from motor neuron disease at his home in St Louis. He was 95.
Knowles, who worked for Monsanto from 1942 to 1986, had been in retirement for 15 years when he was informed in October 2001 that he had won the Nobel.
The prize, for work in a field known as chiral chemistry, was also awarded to Ryoji Noyori of Nagoya University in Japan and Barry Sharpless of the Scripps Research Institute in San Diego.
Many molecules come in two forms, identical in chemical composition but mirror images of each other. The two forms can have very different properties and sharply different effects on the body. For example, one form of the drug L-dopa, called L, reduces Parkinson's symptoms such as tremors and rigidity. But it also comes in another form, D-dopa, which is toxic.
Knowles figured out a way to tweak the manufacturing process to produce more of the most desirable form of certain molecules, including L-dopa. His tool was a catalyst, a substance often used to speed up a chemical reaction. He developed a process called asymmetric hydrogenation, which uses a catalyst not just to speed the reaction but also to skew it to produce 97.5 per cent L-dopa and only 2.5 per cent of the unwanted D form.
Monsanto then began large-scale production of the drug, which is still a mainstay in treating Parkinson's, especially in the disease's early stages.
Knowles was born in Taunton, Massachusetts, and started work for Monsanto after completing a doctorate at Columbia University in 1942. In 2004, he was admitted to the National Academy of Sciences.
He is survived by his wife of 66 years, Nancy, a son, three daughters and four grandchildren.