Two-Time Nobel Winner Linus C. Pauling Dies at 93 : Science: Noted researcher led fight against nuclear weapons and advocated large doses of Vitamin C.

Two-time Nobel Prize winner Linus C. Pauling, a leader in the fight against nuclear weapons and an advocate of vitamin C to prevent cancer, the common cold and other diseases, died Friday. He was 93.

Pauling died at his ranch in the Big Sur area about 7:20 p.m., according to the Linus Pauling Institute of Science and Medicine in Palo Alto. He had been in frail health for several months, according to the institute.

Pauling was the only person ever to win two unshared Nobel Prizes.

“Life has always been something of a puzzle, which I’m always trying to figure out,” he once said.

Pauling won the Nobel Prize in chemistry in 1954 for his research on the nature of the chemical bond that holds molecules together and its use in understanding the structure of such complex substances as protein and antibodies.

He published several books and more than 1,000 scientific papers, continuing to put out about a dozen a year well into his 90s.

“No one has made greater and more varied contributions to modern chemistry” than Pauling, said Purdue University professors Herbert C. Brown and Derek A. Davenport and Cornell University professor R. Hoffmann in their letter nominating him for the Priestly Medal. Pauling won that honor from the American Chemical Society in 1984.

Dr. Francis Crick, co-discoverer of the double-helix structure of the DNA molecule, described Pauling as the “father of molecular biology” and credited him for making possible Crick’s own pioneering work in genetics. Crick and James Watson formulated their model of DNA--the genetic blueprint common to all living things--in 1962.

“It was his example in building models of molecules and dealing with those models creatively that helped us in the discovery of the double helix,” Crick said at a fete for Pauling on his 85th birthday in Pasadena.

Pauling, the son of a Portland, Ore., pharmacist, graduated from Oregon State College (now Oregon State University), obtained a Ph.D. from Caltech and later studied under famed physicist Niels Bohr.

After the development of the atomic bomb, Pauling became a peace advocate and campaigned against nuclear weapons. In 1958, he presented a petition to the United Nations opposing nuclear weapons tests, a document signed by more than 11,000 scientists worldwide.

On Oct. 10, 1963, the effective date for the U.S.-Soviet test ban treaty, he was awarded the 1962 Nobel Prize for peace.

“(It) was a spectacular recognition of Dr. Pauling’s long and strenuous efforts to bring before the people of the world the dangers of nuclear war and the importance of a test ban agreement,” Lee A. Dubridge, president of the California Institute of Technology, said at the time.

Pauling, an outgoing man with bright blue eyes, often wore a floppy beret on his white hair and displayed a wry wit. He said once that the government’s recommended daily allowance of vitamin C “only keeps you from dying of scurvy.”

It was his theories about vitamin C that made Pauling controversial during the past 20 years. He maintained that large doses of ascorbic acid, or vitamin C, can protect people from diseases ranging from the common cold to cancer and extend the life span by decades.

In 1973, Pauling established the Linus Pauling Institute of Science and Medicine in Palo Alto, which continues research on the beneficial effects of vitamin C and other nutrients, on the body.

Pauling himself took 18,000 milligrams of vitamin C a day; the RDA for adults is 60 milligrams. But time and disease caught up with him when he was diagnosed with prostate cancer in December, 1991.

A more detailed obituary on Linus Pauling will appear in Sunday’s editions of The Times