Martin D. Kamen, 1995
Citation:
For his discovery of carbon-14 and its development as a tracer
atom-one of the most powerful research tools of this century-and for
his work on the problem of photosynthesis, including the discovery of
new cytochromes and their role in energy conversion.
Biography
The most well-known of Martin Kamen's many achievements is his
discovery in 1940, in collaboration with the late Sam Ruben, of the
long lived radioactive carbon isotope carbon-14 and his development of
it as a tracer in biological systems. Kamen's work changed
biochemistry in a fundamental way-today, carbon-14 is used to
understand all biochemical reactions involving carbon. Kamen himself
used carbon-14 to understand metabolism and photosynthesis, the most
fundamental process on our planet. Carbon-14 is also used by countless
chemists, biochemists, molecular biologists, medical scientists,
archaeologists, and geologists. The technique of carbon dating has
permitted scientists to date archaeological and anthropological finds
as far back as 60,000 years; and carbon-14 has helped scholars
determine whether pictures were painted by famous artists or by
forgers. Most recently, environmental scientists have been using
carbon-14 to study the distribution and turnover of carbon dioxide in
our deteriorating environment.
In 1937, after completing his doctoral research on neutron
scattering, Kamen began his career as a radiochemist for the legendary
group under Ernest 0. Lawrence at the cyclotron at the University of
California, Berkeley. He used carbon-11 that he made in the Berkeley
cyclotron to trace chemical and biochemical processes but was limited
by the short half-life (21 minutes) of this nuclide. The existence of
the nuclide carbon-14 had been postulated since 1934, but it had never
been directly observed nor characterized. Kamen succeeded in preparing
C-14 in sufficient amounts to determine its beta-emission energy and
lifetime. Remarkably, its extraordinarily long half-life (5,700 years)
differed from theoretical expectation.
Two basic themes recurred in Kamen's pioneering radiocarbon
studies: photosynthesis and the related general problem of CO2
assimilation. In 1938 he demonstrated, in collaboration with Sam Ruben
and others, that the source of molecular oxygen in photosynthesis is
water and not carbon dioxide.
During the war years Kamen's liberal ideas and outgoing personality
caused him to be watched by government security, including the F.B.I.
In 1944, he was declared security risk and dismissed from the Berkeley
Radiation Lab. A few years later he was called before the House
Un-American Activities Committee. Kamen fought in the courts for over
ten years to clear his name and to regain his passport, which had been
denied whenever he had been invited to attend scientific meetings
abroad.
In 1945, he moved to the Mallinckrodt Institute of Radiology,
Washington University School of Medicine, where he supervised
cyclotron production of radioisotopes for medical research. He
continued his study of photosynthesis and cytochromes (the respiratory
proteins basic to reduction of oxygen) using carbon-14 as a tracer by
collaborating with biochemists throughout the university. With keen
scientific intuition, he chose to use bacteria instead of green plants
as test organisms. This change, related to his earlier studies on
bacteria at Berkeley, was influenced also by his familiarity with the
attitudes of comparative biochemistry, a viewpoint that emphasizes
general biochemical and evolutionary relationships and 'guides
research accordingly. These studies, ranging over the whole field of
microbiology stimulated a rapidly expanding series of studies in the
laboratories of his collaborators and others.
In 1947 he wrote what immediately became the primary reference work
for several decades on the use of radioactive tracers, Radioactive
Tracers in Biology:An Introduction to Tracer Methodology. This work,
first published in 1947, went through three editions incorporating new
techniques, and three reprinting, through 1965. It remains a classic
reference on basic nuclear science, tracer methodology and technique.
During, the 1950s and 1960s, his studies on the metabolism of
photosynthetic bacteria resulted in a number of important discoveries,
notably nitrogen fixation and the photoevolution of molecular hydrogen
(with H. Gest, a graduate student at the time), and the so-called
suicide procedure; to trace mechanisms of DNA duplication (with A.V.
Hershey). After he and Leo Vernon discovered the C-tvpe cytochronie in
anaerobic bacteria, he began a series of pioneering researches on
bacterial iron proteins. They performed the first characterization of
a bacterial cytochrome and from this there emerged a wholly new area
the comparative biochemistry of cytochromes-which stimulated
discoveries of many new classes of iron proteins.
Kamen became Professor of Biochemistry at Brandeis University
(1957-61) and Professor of Chemistry at the University of California
at San Diego (1961-1978). From 1967-1970, he spent every six months as
Director of Research at the Centre National de la Recherche
Scientifique Laboratorle de Photosyntheses in Gif-Sur-Yvette, France.
He taught at the University of Southern California, where he was
Director of the Chemical-Biolocical Development Laboratory (I
974-1977) and Director of Molecular Biology (I 978). Currently he is
Professor Emeritus at the University of California at San Diego and at
the University of Southern California. Professor Kamen continued to
teach until his 80s. Martin Kamen was born in 1913 in Toronto. He
earned his BS and Ph.D. degrees in Chemistry and Physical Chemistry,
respectively, from the University of Chicago. Dr. Kamen has published
over 300 scientific papers, which demonstrates the range and
significance of his work. His textbook on tracer methods Isotopic
Tracer Methods in biology was highly influential in introducing,,
tracer methodology, , to biochemistry. He textbook Primary Process in
Photosyntheses (1963) is a classic work in its field. He wrote an
autobiography, Radiant Science, Dark Politics: A Memoir of the Nuclear
Age (1985), which focuses on his life from 1937 to 1957.
He has received many honorary degrees, including those from the
University of
Chicago, Washington University, University of Illinois, Brandies
University, University of Freilbur, in Germany, and the Welzmann
Institute of Science in Israel. His awards include the C.F. Kettering,
Research Award (1963-1970), the C. F. KetterinG Award for Excellence
in Photosynthesis (1968) , the Merck Award of the American Society of
Biological Chemists (1982), and the Einstein Award of the World
Cultural Council (1990). Dr. Kamen is a member of the National Academy
of Sciences, the American Academy of Arts and Sciences, and the
American Philosophical Society.