STOCKHOLM (Reuters) - John Fenn of the United States, Japan's Koichi Tanaka and Kurt Wuethrich of Switzerland won the 2002 Nobel Prize in Chemistry on Wednesday for advances in the understanding the process of life.

They share the $1 million prize for developing powerful analytical tools to study large molecules like proteins, which can lead to new drugs to tackle disease, the Royal Swedish Academy of Sciences said.

"Their work has paved the way for the future finding of a cure for cancer," said Bengt Norden, chairman of the Nobel committee for chemistry. "Without it, there would be no modern pharmaceuticals."

The three scientists developed techniques that can be applied to diagnose of cancer early, monitor sports doping, analyze environmental pollution and improve control of foodstuffs.

Fenn and Tanaka created a process to ascertain the size and quality of proteins, one of the building blocks of life contained in cells, by developing the widely used technique of mass spectrometry to analyze large molecules.

Wuethrich developed a tool which identifies the structure of proteins in the cells, making it possible to study proteins in an environment similar to that of the living cell.

Describing their work as a "revolutionary breakthrough," the academy said it meant three-dimensional images of proteins could be produced to allow scientists to see proteins and understand how they function in cells.

STATE OF SHOCK

The new laureates reacted to the news of the award with jubilation and surprise.

"I am in a state of shock," Fenn told Reuters in a telephone interview minutes after the prize was announced. "I am not exactly coherent."

Fenn, 85, is a research professor at Virginia Commonwealth University at Richmond, Virginia. He said he had known his work on the analysis of molecules would have practical uses one day.

"I knew it was going to be useful and popular," he said. "It's gotten popular in a way far beyond my wildest dreams."

Tanaka, 43, is the youngest chemistry laureate since 1967 and the second Japanese Nobel winner this year following physics laureate Masatoshi Koshiba. He works at precision equipment maker Shimadzu Corp in Kyoto, Japan.

Wuethrich, 64, is the fifth Swiss chemistry laureate, and the first since 1991. He said the timing of the prize was perfect because he was on the verge of retiring from his current position.

"I am in the process of building up a new lab in the U.S. because I have to stop working in Switzerland next year. I assume that this can be used very well for a new start in California," he told Swiss radio.

Wuethrich built a reputation in research on the way rogue proteins relate to diseases like Mad Cow Disease.

"We were able to develop methods to observe the molecules that keep us alive," he told Swiss radio. "I seem to have struck gold."

Fenn and Tanaka will share one half of the prize and Wuethrich will receive the other half.