Paul D. Boyer in 1997. (Lacy Atkins/AP)

Paul D. Boyer, a UCLA biochemist who shared the 1997 Nobel Prize in chemistry for his discoveries describing “a beautiful little molecular machine” that helped produce the chemical energy transfers found in all living cells, died June 2 at his home in Los Angeles. He was 99.

The cause was respiratory failure, said Stuart Wolpert, a spokesman for the University of California at Los Angeles, where Dr. Boyer was a longtime faculty member.

Dr. Boyer spent years investigating the functioning of adenosine triphosphate (ATP), the basic energy source in all living cells. Scientists had known of the existence of ATP for decades but had not been able to determine how it was formed.

“ATP is the currency of life,” David S. Eisenberg, who holds the Paul D. Boyer chair in microbiology at UCLA, said in an interview. “It makes everything run. It translates its chemical energy to other forms of energy.”

Over the years, Dr. Boyer conducted molecular-level experiments in kinetics and thermodynamics that gave him an unprecedented understanding of ATP molecules. In a 1974 scientific paper, he proposed that a catalytic enzyme known as ATP synthase acted as, in effect, a tiny motor to produce the chemical reactions that resulted in the formation of ATP.

Dr. Boyer showed how the presence of hydrogen ions transformed the components of ATP through a chemical synthesis into the complete ATP molecule. He described ATP synthase as a tiny rotor and shaft that facilitated the chemical process but was not part of the final product.


Dr. Boyer signs a student's robe at UCLA in 1997. (Hector Mata/AFP/Getty Images)

“It was the first atomic picture of a molecular machine,” Eisenberg said.

Dr. Boyer suggested that the ATP synthase consisted of three chambers that changed shape during the chemical process through a kind of internal rotation, similar to a wheel and shaft.

“It’s the only known enzyme that has this rotational mechanism,” he told the Los Angeles Times in 1997. “It’s like a three-cylinder motor.”

He described his discovery as “a beautiful little molecular machine.”

Other scientists considered Dr. Boyer’s idea wildly far-fetched. In 1994, British scientist John E. Walker confirmed Dr. Boyer’s earlier findings by establishing the structure of the ATP synthase enzyme.

Dr. Boyer and Walker shared half of the 1997 Nobel Prize in chemistry. The other half of the prize went to Danish scientist Jens C. Skou, who worked on other aspects of enzymes and ATP. Skou died May 28.

Dr. Boyer’s work continues to be a foundation of scientific studies of ATP and has helped explain what he called “the marvel of the living cell.”

Paul Delos Boyer was born July 31, 1918, in Provo, Utah. His father was an osteopathic physician and his mother a homemaker who died of Addison’s disease when her son was 15.

“Discoveries about the adrenal hormones, that could have saved her life, came too late,” Dr. Boyer wrote in a biographical statement for the Nobel Prize website. “Her death contributed to my later interest in studying biochemistry.”

After graduating in 1939 from Brigham Young University in his home town, he studied biochemistry at the University of Wisconsin, where he received a master’s degree in 1941 and a doctorate in 1943. He then did postdoctoral research at Stanford University before joining the Navy late in World War II.

“I became what is likely the only seaman second-class that has had a nearly private laboratory at the Navy Medical Research Institute in Bethesda, Maryland,” he wrote.

After the war, Dr. Boyer was on the faculty of the University of Minnesota before moving to UCLA in 1963. He directed the university’s Molecular Biology Institute from 1965 to 1983 and retired from teaching in 1990.

He edited an 18-volume series, “The Enzymes,” served on the editorial boards of several scientific journals and was a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences. He contributed much of his Nobel earnings to the universities where he studied and taught.

Dr. Boyer was adept with his hands and installed the plumbing and electrical wiring in his house in the Bel Air section of Los Angeles.

Survivors include his wife of 78 years, the former Lyda Whicker of Los Angeles; two daughters; eight grandchildren; and six great-grandchildren. A son died in 2001.

In his statement for the Nobel website, Dr. Boyer noted that he had abandoned all religious belief and openly wondered why “the man-made concept of a God” was allowed to appear on U.S. currency.

He emphasized that the values of science and skepticism were essential to the political and intellectual life of a free society.

“It is disappointing how little the understanding that science provides seems to have permeated into society as a whole,” he said. “Religious fundamentalists successfully oppose the teaching of evolution, and by this decry the teaching of critical thinking. . . .

“If we fail to teach our children the skills they need to think clearly, they will march behind whatever guru wears the shiniest cloak. Our political processes and a host of human interactions are undermined because many have not learned how to gain a sound understanding of what they encounter.”