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.
The next two years were spent working with the intellectual giant Michael Polanyi in Manchester, England, where Melvin became interested in phthalocyanines. This first incursion into photochemistry was later to lead to chlorophyll, photosynthesis, and artificial photosynthetic membrane models. A chance visit with Joel Hildebrand at Manchester resulted in an invitation from Gilbert N. Lewis to join the chemistry faculty at the University of California. So, in 1937 Calvin arrived as an instructor at Berkeley, where he was to remain for the rest of his life. He was the first non-Berkeley graduate to be hired by the Department of Chemistry in more than a quarter century. His work with G. N. Lewis developed the photochemistry of colored porphyrin analogs and their coordination of iron and other central metals. Melvin was at home in discussions of the excited triplet states of chlorophyll and intermediates in the energy transfer processes of photosynthesis, subjects that clearly passed over the heads of most plant biologists of that period. Such discussion later involved James Franck, A. A. Krasnovsky, A. Terenin, George Porter, R. G. W. Norrish, Bill Arnold, Sterling Hendricks, and G. O. Schenk.
Tribute Samuel Ruben’s contributions to research on photosynthesis
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 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.
Samuel Rubin Foundation | Foundation History
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.
At the time, Sam Ruben and Martin Kamen were 27 years old, ..
Sam Ruben and Martin Kamen’s development of application of radioactive carbon for the study of carbon dioxide fixation provided impetus and techniques for following the path of carbon in photosynthesis.