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Calvin, Melvin

American Biochemist
1911-1997

Melvin Calvin was a biochemist whose prolific career included fundamental work on the biochemistry of photosynthesis. His work led to a Nobel Prize and had Time magazine calling him "Mr. Photosynthesis."

Calvin was born in St. Paul, Minnesota, on April 8, 1911, of immigrant parents. The family moved to Detroit, Michigan, where Calvin graduated from high school in 1927. He graduated from the Michigan College of Mining and Technology (now Michigan Technological University) as its first chemistry major in 1931. He received his Ph.D. from the University of Minnesota in 1935. He worked two years at Manchester University with British chemist and philosopher Michael Polanyi (1875-1946), who introduced him to the multidisciplinary approach that later characterized his own scientific career.

In 1937 Calvin became an instructor at the University of California at Berkeley and remained there for the rest of his career. He eventually became a professor (1947), director of the Laboratory of Chemical Biodynamics (1963), and associate director of the Lawrence Radiation Laboratory (1967; now the Lawrence Berkeley Laboratory).

Together with American physical chemist Gilbert Newton Lewis (1875-1946), Calvin studied the color of organic compounds, which introduced him to the importance of the electronic structure of organic molecules. He collaborated with chemist G. E. K. Branch and cowrote The Theory of Organic Chemistry (1941), the first American book on the subject to use quantum mechanics.

In 1942 Calvin married Genevieve Jemtegaard, a juvenile probation officer who spent a great deal of time in her husband's laboratory, both assisting and collaborating with him. After their first child died of Rh incompatibility they sought to determine the chemical factors causing the illness. After the 1973 oil embargo they sought new fuel sources from plants (e.g., the genus Euphorbia) to convert solar energy into hydrocarbons, an economically unsuccessful project.

During World War II (1939-41) Calvin devised a method for obtaining pure oxygen from the atmosphere onboard destroyers or submarines. He purified and decontaminated the irradiated uranium in fission products and isolated and purified plutonium by his solvent extraction process.

After the radioisotope carbon-14 (because of its long-lived radioactivity, it could be used to follow otherwise untraceable chemical reactions) became available, Calvin began his work on the chemical pathways of photosynthesis. This occupied him from 1946 to 1961 and won him the 1961 Nobel Prize in chemistry. He introduced carbon dioxide (CO₂) labeled with carbon-14 as a tracer into a thin, round flask filled with the single-cell green alga Chlorella pyrenoidosa in suspension. The apparatus was illuminated, allowing the alga to incorporate the labeled CO₂ into compounds involved in photosynthesis. Calvin isolated and identified the radioactively labeled constituents, thus determining the steps by which CO₂ is converted into carbohydrates. This set of steps is now known as the Calvin-Benson cycle. Using isotopes, he also traced the path of oxygen in photosynthesis.

Calvin worked on chemical evolution and organic geochemistry, and he examined the organic constituents of Moon rocks for the National Aeronautics and Space Administration. His varied research interests also included photochemistry, free radicals, artificial photosynthesis, radiation chemistry, brain chemistry, the molecular basis of learning, and the philosophy of science.

In 1987 Genevieve died of cancer. Because Calvin's personal and professional life had been built around her presence, her loss was a blow from which he never recovered. Calvin died in Berkeley, California, on January 8, 1997, after several years of declining health.