The Path of Life

A watershed in biochemistry--Melvin Calvin's scientific paper detailing the complete biochemical pathway through which plants convert carbon dioxide from the atmosphere into carbohydrates--was published 36 years ago, in the 16 March 1962 issue of Science. Calvin, a former chemist at the University of California, Berkeley, who died last year, achieved this fundamental discovery using radiolabeled carbon dioxide, which became available after World War II, to track the fate of carbon in plants and to determine the metabolic reactions that take place at each step. The elucidation of key steps in this biochemical pathway had won Calvin the 1961 Nobel Prize in chemistry; during his acceptance speech at the Nobel ceremony in December that year, Calvin previewed his paper on the entire pathway.