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Nelson J. Leonard, 90; Chemist's Research Had Far-Reaching Effects

October 12, 2006|Thomas H. Maugh II | Times Staff Writer

Nelson J. Leonard, a world-acclaimed chemist who combined his synthetic prowess in the laboratory with a powerful bass-baritone voice that made him a featured soloist with symphony orchestras in the Midwest, died of cancer Monday at his home in Pasadena. He was 90.

Leonard spent nearly half a century at the University of Illinois before concluding his career at Caltech.

"Nelson was one of the most important chemists of the 20th century," said his colleague Jack Roberts, an emeritus professor at Caltech.

Steven C. Zimmerman, head of the chemistry department at Illinois, said of Leonard: "He was way ahead of his time scientifically, in the sense that he collaborated with biochemists and biologists long before interdisciplinary research was fashionable. He was one of the first people in the country to use chemistry to understand biology."

Beginning in the 1960s, Leonard and his students synthesized a variety of analogues of chemicals that were known to play a role in the growth and development of plants. In a fruitful collaboration over the following 20 years, these were tested by plant physiologist Folke Skoog of the University of Wisconsin.

Several of the chemicals proved to be potent stimulators of plant-cell growth, division and differentiation, and they are now widely used in horticulture to initiate the growth of intact plants, flowers and trees from tissue culture.

In the 1970s, Leonard met Argentine chemist Gregorio Weber, who convinced him that fluorescent variants of the nucleotide components of DNA and RNA would be useful tools for research to show where in the cell particular chemicals were located. Leonard's laboratory synthesized many fluorescent chemicals that are now broadly used in research, especially a variant of adenosine triphosphate, which plays a key role in nucleotide chemistry and in energy transfer within the cell.

Not only did fluorescent chemicals show scientists where chemicals were in the cell, but studies of their lifetime and polarization also showed how chemicals were attached to an enzyme or structural protein.

The fluorescent molecules "enabled a slew of very basic biochemistry and molecular biology studies that otherwise couldn't have been done," Zimmerman said. "They have led to much of what we know about how cells work."

Nelson Jordan Leonard was born Sept. 1, 1916, in Newark, N.J., and grew up in Mount Vernon, N.Y. His father was a salesman and his mother a housewife. Leonard attributed his interest in his future field to a chemistry set he had in childhood and to a particularly good chemistry teacher in high school.

Leonard received his bachelor's degree from Lehigh University in Bethlehem, Pa., then went to Oxford University on a Rhodes scholarship. But World War II intervened in 1939, and he was forced to return home from England, enrolling at Columbia University, where he received his doctorate in 1942.

Through family connections, he had met a young Dutch woman, Louise Cornelie Vermey, and become engaged. She was forced to spend the war in the Netherlands, however, and he did not see her again until 1945. In 1947, he was finally able to arrange for her to come to the United States, and they were married.

After receiving his doctorate, Leonard went to Illinois, where he thought he would spend a year before returning to New York. He found it so congenial, however, that he stayed 44 years.

During the war, he worked on the synthesis of the malaria drug chloroquine, completing it in time for the drug to be widely used in the Pacific campaign.

After the war, he got a temporary job overseas with the U.S. Army examining the research publications and reports of the German chemical company I.G. Farbenindustrie. He and his colleagues found several processes that were later adopted by American companies, including one technique to improve the manufacture of synthetic rubber.

The job also had a more important benefit: It gave him a chance to see Louise again.

When Leonard returned to Illinois, he resumed his singing career. A solo performer since the age of 10, he had wide experience as a church soloist, a recitalist and an oratorio singer. While at Oxford, he had been the bass soloist of the Lincoln College Choir.

After the war, he performed with the Chicago Symphony, St. Louis Symphony and Cleveland Orchestra, receiving glowing reviews. Students at Illinois often recalled passing outside his office and hearing him singing.

But when Leonard was elected to the National Academy of Sciences in 1955, he decided that if his peers had chosen him for the prestigious position, he had "better do something about it."

He retired from professional music, although he continued to sing in church and in performances on campus. He remained involved in the musical world in Pasadena, where he served on the board of the Pasadena Symphony.

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