Sir Hans Adolf Krebs
Biography of Sir Hans Adolf Krebs
Hans Adolf Krebs in 1953 received the Nobel Prize for Physiology or Medicine for the discovery in living organisms of the series of chemical reactions known as the tricarboxylic acid cycle, or Krebs cycle. He shared the Prize with Fritz Albert Lipman, USA, who received the prize for his discovery of coenzyme A and its importance to the intermediate metabolism.
Hans Adolf Krebs descended from Jewish-Silesian ancestry. He was the son of Georg Krebs, an ear, nose, and throat surgeon who had established a successful practice in Hildesheim. His mother was Alma Krebs, née Davidson. He was educated at the Gymnasium Andreanum in Hildesheim and between the years 1918 and 1923 studied medicine at the Universities of Göttingen, Freiburg im Breisgau, and Berlin. After one year at the Third Medical Clinic of the University of Berlin he took, in 1925, his M.D. degree at the University of Hamburg. He spent the following year as a staff member in the chemistry department at the Institute of Pathology at Berlin, where he was exposed to the latest developments in biochemical research.
In 1926 Krebs was appointed assistant to the 1931 Nobel laureate, professor Otto Warburg (1883-1970) at the Kaiser Wilhelm Institute for Biology at Berlin-Dahlem, where he remained until 1930. He returned to hospital work in 1930, first at the Municipal Hospital at Altona under professor Leopold Lichtwitz (1876-), and later at the Medical Clinic of the University of Freiburg im Breisgau under professor S. J. Thannhauser. He became Privatdozent in 1932.
His appointment at Freiburg was terminated by the National Socialist Government after only a few months, and he was forced to emigrate to England in 1933, where he was invited by Sir Frederick Gowland Hopkins (1861-1947), the 1929 Nobel Prize winner, to work at the School of Biochemistry, Cambridge. He held a Studentship here until 1934, when he was appointed Demonstrator of Biochemistry in the University of Cambridge.
In 1935, Krebs was appointed lecturer in Pharmacology at the University of Sheffield and in 1938 lecturer-in-charge of the Department of Biochemistry then newly founded there. In 1945 this appointment was raised to that of Professor, and of Director of a Medical Research Council's research unit established in his Department.
Krebs served on the faculty of Oxford University from 1945 to 1967. During the war he worked in the field of nutritional requirements, with particular attention to the dietary roles of vitamins A and C. In 1954 he was appointed Whitley Professor of Biochemistry in the University of Oxford and the Medical Research Council's Unit for Research in Cell Metabolism was transferred to Oxford.
A frequent visitor to Israel, Krebs lent his effort to the development of the Hebrew University in Jerusalem. In 1960 he was awarded the Doctor honoris causa, acknowledging his considerable contribution to the establishment of the university’s biochemistry department. The Israelis expressed their respect and gratitude again in 1972, appointing Krebs honorary fellow of the Weismann Research Institute, their nation’s highest scientific honour.
A humble and occasionally sardonic man, Krebs suggested to a meeting of the American Philosophical Society in 1970 that the way to impress upon governments the value of scientific exploration would be to do away with the vast amount of wasteful and gratuitous research he described as ”occupation therapy for the university staff.”
Professor Krebs' researches have been mainly concerned with various aspects of intermediary metabolism. Among the subjects he has studied are the synthesis of urea in the mammalian liver, the synthesis of uric acid and purine bases in birds, the intermediary stages of the oxidation of foodstuffs, the mechanism of the active transport of electrolytes and the relations between cell respiration and the generation of adenosine polyphosphates.
In 1932, at the University of Freiburg im Breisgau, with the German biochemist Kurt Henseleit, Krebs discovered a self-perpetuating series of cellular reactions, now known as the urea cycle, by which ammonia is converted to urea in mammalian tissue; the urea, far less toxic than ammonia, is subsequently excreted in the urine of most mammals. This cycle also serves as a major source of the amino acid arginine.
At Sheffield (1935-1954) Krebs measured the amounts of certain four-carbon and six-carbon acids generated in pigeon liver and breast muscle when sugars are oxidized completely to yield carbon dioxide, water, and energy.
In 1937 Krebs was able to demonstrate the existence of a cycle of chemical reactions that combines the end-product of sugar breakdown, later shown to be an «activated» form of the two-carbon acetic acid, with the four-carbon oxaloacetic acid to form citric acid. The cycle regenerates oxaloacetic acid through a series of intermediate compounds while liberating carbon dioxide and electrons that are immediately utilized to form high-energy phosphate bonds in the form of adenosine triphosphate (ATP; the chemical energy reservoirs of the cell).
Among his many publications is the remarkable survey of energy transformations in living matter, published in 1957, in collaboration with Hans Kornberg, which discusses the complex chemical processes which provide living organisms with high-energy phosphate by way of what is known as the Krebs or citric acid cycle.
Krebs was elected a Fellow of the Royal Society of London in 1947. In 1954 the Royal Medal of the Royal Society, and in 1958 the Gold Medal of the Netherlands Society for Physics, Medical Science and Surgery were conferred upon him. He was knighted in 1958 and the Royal Society awarded him its Copley Medal in 1961. He held honorary degrees from the Universities of Chicago, Freiburg-im-Breisgau, Paris, Glasgow, London, Sheffield, Leicester, Berlin (Humboldt University) and Jerusalem.
He married Margaret Cicely Fieldhouse, of Wickersley, Yorkshire, in 1938. They had two sons, Paul and John, and one daughter, Helen.
Krebs was knighted in 1958 and the Royal Society awarded him its Copley Medal in 1961.