(1899–1986) German–American biochemist
After attending the university in his native city of Königsberg (now Kaliningrad in Russia), Lipmann studied in Berlin, where he obtained his MD in 1922 and his doctorate in 1927. He then worked with Otto Meyerhof in Heidelberg and taught at the Kaiser Wilhelm Institute in Berlin (1927–31), but with the rise of the Nazis decided to abandon Germany and consequently accepted a position with the Carlsberg Foundation in Copenhagen. In 1939 he moved to America, where he worked at the Cornell Medical School (1939–41), Harvard (1941–49), and the Massachusetts General Hospital in Boston (1949–57), before becoming professor of biochemistry at the Rockefeller Institute for Medical Research in New York, a post he occupied until his retirement in 1970.
It was widely known that the breakdown of such carbohydrates as glucose provides energy for the body's cells, but just how the cell obtains the energy released was a mystery. Lipmann's work, recently described by a historian of molecular biology as “the most magnificent achievement of late-classical biochemistry,” began in 1937, when he was working on the breakdown of glucose by a particular bacterium. Quite fortuitously he found that a certain oxidation would not proceed without the addition of some phosphate.
This was all he needed to see that the real purpose of metabolism was to deliver energy into the cell. Lipmann sought for the phosphate that delivered the energy and found a molecule, adenosine triphosphate (ATP), which had been identified as the probable source of muscular energy by K. Lohmann in 1929. The molecule consisted of adenosine monophosphate (a nucleotide of the nucleic acid RNA), with the addition of two energy-rich phosphate bonds. When ATP is hydrolyzed to adenosine diphosphate (ADP), some of this energy is released ready for use in the cell.
It was not for this work, however, that Lipmann shared the 1953 Nobel Prize for physiology or medicine with Hans Krebs but for his discovery of coenzyme A and its importance for intermediary metabolism in 1947. While working on the role of phosphate in cell metabolism, Lipmann discovered that a heat-stable factor was acting as a carrier of acetyl (CH3CO–) groups. It could not be replaced by any other known cofactor. Lipmann eventually isolated and identified what he termed ‘cofactor A’, or CoA (the A stands for acetylation), showing it to contain pantothenic acid (vitamin B2). He also realized that the two-carbon compound in the Krebs cycle that joined with oxaloacetic acid to form citric acid was in fact acetyl CoA. The coenzyme was soon shown to have wider application than the Krebs cycle, when in 1950 Feodor Lynen found that it played a key role in the metabolism of fats.
Subjects: Science and Mathematics.