Martin David Kamen (August 27, 1913, Toronto – August 31, 2002, Montecito, California) was an American chemist who, together with Sam Ruben, co-discovered the synthesis of the isotope carbon-14 on February 27, 1940, at the University of California Radiation Laboratory, Berkeley. He also confirmed that all of the oxygen released in photosynthesis comes from water, not carbon dioxide, in 1941.
Kamen was the first to use carbon-14 to study a biochemical system, and his work revolutionized biochemistry and molecular biology, enabling scientists to trace a wide variety of biological reactions and processes. Despite being blacklisted for nearly a decade on suspicion of being a security risk, Kamen went on to receive the Albert Einstein World Award of Science in 1989, and the U.S. Department of Energy's 1995 Enrico Fermi award for lifetime scientific achievement.
Kamen was born on August 27, 1913, in Toronto, the son of Russian-Jewish immigrants. He grew up in Chicago. Interested in classical music, he initially entered the University of Chicago as a music student before changing his major from music to chemistry. Although he gave up music as a career, Kamen continued to play the viola at a high professional level during the rest of his life.
Kamen received a bachelor's degree in chemistry from the University of Chicago in 1933. In 1936, Kamen earned a PhD in physical chemistry from the same university after working with William D. Harkins on "Neutron-Proton Inter-action: The Scattering of Neutrons by Protons."
From 1936 to 1944, Kamen worked at the Radiation laboratories at the University of California, Berkeley.
Kamen gained a research position in chemistry and nuclear physics under Ernest Lawrence by working without pay for six months, until he was hired to oversee the preparation and distribution of the cyclotron's products.
Kamen's major achievements during his time at Berkeley included the co-discovery of the synthesis of carbon-14 with Sam Ruben in 1940, and the confirmation that all of the oxygen released in photosynthesis comes from water, not carbon dioxide, in 1941.
From 1941 to 1944, Kamen and others at the Berkeley Radiation Laboratory worked on the Manhattan Project.
In 1943, Kamen was assigned to Manhattan Project work at Oak Ridge, Tennessee, where he worked briefly before returning to Berkeley.
In spite of the fact that his scientific capabilities were unquestioned, Kamen was fired from Berkeley in July 1944 on suspicion of being a security risk. He was suspected of leaking nuclear weapons secrets to the Soviet Union (which at the time was allied with the US and others against Nazi Germany).
Kamen was unable to obtain another academic position until 1945 when he was hired by Arthur Holly Compton to run the cyclotron program in the medical school of Washington University in St. Louis. Kamen taught the faculty how to use radioactive tracer materials in research, and continued to develop his interests in biochemistry. His book Isotopic Tracers in Biology (1947) became a standard text on tracer methodology and highly influenced tracer use in biochemistry.
In 1957, Kamen moved to Brandeis University in Massachusetts where he helped Nathan Oram Kaplan to establish the Graduate Department of Biochemistry.
In 1961 Kamen joined the University of California, San Diego, where he founded a biochemistry group as part of the university's new department of chemistry.
Kamen remained at the University of California, San Diego, retiring from teaching (but not research) to become an emeritus professor in 1978.
Martin Kamen died August 31, 2002, at the age of 89 in Montecito (Santa Barbara), California.
Although carbon-14 was previously known, the discovery of the synthesis of carbon-14 occurred at Berkeley in 1940 when Kamen and Sam Ruben bombarded graphite in the cyclotron in hopes of producing a radioactive isotope of carbon that could be used as a tracer in investigating chemical reactions in photosynthesis. Their experiment resulted in production of carbon-14.
By bombarding matter with particles in the cyclotron, radioactive isotopes such as carbon-14 were generated. Using carbon-14, the order of events in biochemical reactions could be elucidated, showing the precursors of a particular biochemical product, revealing the network of reactions that constitute life.
Kamen confirmed in 1941 that all of the oxygen released in photosynthesis comes from water, not carbon dioxide. He also studied anoxygenic photosynthetic bacteria, the biochemistry of cytochromes and their role in photosynthesis and metabolism, photosynthetic bacteria, the role of molybdenum in biological nitrogen fixation, the role of iron in the activity of porphyrin compounds in plants and animals, and calcium exchange in cancerous tumors, making substantial contributions.