Two Americans shared the Nobel Prize in medicine Monday for discovering a basic process in human cells that is linked to cancer and rejection of transplanted organs.
Dr. Edwin Krebs, 74, and Edmond Fischer, 72, who has dual Swiss-American nationality, were awarded the $1.2-million prize for their research on "reversible protein phosphorylation."
"It is one of the most important (chemical) reactions by which cells are turned on and off," Fisher said from his home in Seattle. "Tens of thousands of reactions in the cell can be regulated. It's involved in every aspect of cell growth, proliferation, differentiation."
Fischer and Krebs, who are senior researchers at the University of Washington, began working together in the 1950s.
They discovered an important class of enzymes called protein kinases. These enzymes turn on essential biological functions inside the cell through activation of proteins. Other enzymes called phosphatases regulate deactivation.
The work by Fischer and Krebs has helped scientists understand how the drug cyclosporin prevents the rejection of transplanted organs, and why certain cancers and allergies develop.
"It absolutely can lead the trail to a cure for cancer," said Fischer.
The Nobel Assembly at the Karolinska Institute announced the winners before it could reach them by telephone, so Krebs and Fischer heard the news from the U.S. media.
Krebs was at home, on the Columbus Day holiday, but did not get the message for five hours because he is partially deaf and did not hear his telephone ringing. He was told of the award by an Associated Press photographer, and later told the Nobel Assembly by telephone, "It makes it all believable to hear it from you."
"We were certainly among the very first to do this kind of work," said Krebs, a native of Lansing, Iowa.
The award is based on research done by Fischer and Krebs from 1955 through 1965. It took 10 years for the scientific community to begin to understand the field, which is now one of the most important in modern research, said Dr. Hans Wigzell of the Nobel Assembly's research committee.
"Then it took off like a rocket. Now 10 percent of all biology articles in journals like Nature or Science deal with their field," Wigzell said.
Fischer said that back in the 1950s he had not realized the importance of their discoveries. "That's not the way it works," he said. "In fact, when we found out this reaction, we didn't know if it was something very unique, very unimportant.
"Then over the years many many people working in this area have developed the field and now we know that it's involved in just about every reaction inside the cell," he said.
Fischer is researching cell transformation, which is connected to the development of cancer.
Krebs is concentrating on hormonal regulation, such as in diseases like diabetes.
Members of the Nobel Assembly predict that it will be possible, but difficult, to develop medicines based on Krebs' and Fischer's prizewinning work that can be tailored to block or stimulate certain functions.
Besides cyclosporin, no such drugs are currently in production, although research is under way in various fields, including development of drugs to prevent allergic reactions.