Hans Adolf Krebs - Physicians, Timeline and Facts

Hans Adolf Krebs was born on August 25, 1900 to Georg and Alma Krebs in Hildesheim, Germany. His father was an ENT surgeon. Young Krebs was the second of the three children born to the couple.

As a child, Krebs was shy and introvert but at the same time, industrious and well-organized. He had a deep seated love for architecture and cultivated a liking for music, poetry, literature and art. He was a nature lover and pursued his hobby of botanical collecting. He practiced the piano as well.

Academically, Krebs gained his formal education from the famous old Gymnasium Andreanum. He was an above average student and did well in most subjects; history being his favourite subject.

When Krebs turned fifteen, he envisioned to follow his father’s footsteps and make a career as an ENT surgeon. He started reading books on medicine and planned to train under his father before he could independently practice.

With the outbreak of World War I, he was drafted in the Imperial German Army in September 1918. At the time, he was six months short of completing his secondary education. Within two months, the war ended and so did Krebs’ subscription.

In December 1918, Krebs pursued his passion and enrolled at the University of Göttingen to study medicine. Following year, he was transferred to the University of Freiburg. It was while at the university that Krebs became interested at research.

In 1920, Krebs first met Wilhelm von Mollendorf, a leader in the field of vital staining. Under Mollendorf, Krebs studied the staining effects of different dyes on muscle tissue. In 1923, he published his first technical paper on tissue staining technique.

By the time Krebs completed his medical course in 1923, he was convinced of pursuing a scientific career. Nevertheless, for making a living, he planned to enter internal medicine. In 1924, Krebs spent a year at the Third Medical Clinic at the University of Berlin to obtain a medical license.

While at the University of Berlin, Krebs combined clinical practice with experimental work. However, he soon realized the potential in himself as a powerful independent investigator and turned to take up medical research work in the field of chemistry. For the same, he studied at the Department of Chemistry at the Pathological Institute of the Charité Hospital, Berlin, in 1924. Following year he gained his M.D. degree from the University of Hamburg.

In 1926, Krebs began his career as a research assistant to great biochemist Otto Heinrich Warburg at the Kaiser Wilhelm Institute for Biology in Dahlem, Berlin. It was while apprenticing with Warburg that Krebs learned about tissue slice and manometric methods to measure the rate of respiration and glycolysis of cancer cells.

Upon mastering the manometric tissue slice techniques, Krebs thought of applying it to study intermediary metabolism. He was aware that not much was known about the series of reactions between the foodstuffs that enter the body and their final decomposition products and believed that using the technique he could link the unbroken sequences of chemical equation and thus bring about a revolution in biochemistry. However, the idea did not appeal Warburg and Krebs side-lined it for future.

In 1930, Krebs completed four years of his association with Warburg. During the time, he came up with about 16 publications. With Warburg no longer requiring Krebs’s services, the latter took up a position in clinical medicine as an assistant in the Department of Medicine at the Municipal Hospital in Altona, lacking the conviction of investigating independently. Next year, he moved to the Medical Clinic of the University of Freiburg.

At Freiburg, Krebs followed both clinical and research career. He looked after 40 patients and at the same time, collaborated with a fellow research student Kurt Henseleit, to hypothesize the metabolic pathway for urea formation. The two carried out numerous experiments that only confirmed that amino acids and ammonia can produce urea in isolated liver slices and in no other animal tissues, as opposed to previous belief that amino acids and ammonia give rise to urea in the liver.

Krebs and Henseleit discovered the ornithine cycle of urea synthesis, which is often referred to as the Krebs-Henseleit cycle. They started working on the possible method for the synthesis of arginine. Using the Warburg manometer, they mixed a slice of liver with purified ornithine and citrulline. The result was citrulline acted as a catalyst in the metabolic reactions of urea from ammonia and carbon dioxide. In 1932, together with Henseleit, Krebs published the discovery thus establishing the ornithine cycle. It became the first metabolic cycle to be discovered.

In 1933, Krebs’ scientific progress met with a tragic halt. Hitler had assumed power and decreed the Law for the Restoration of the Professional Civil Service under which all non-Aryans and anti-Nazis were removed from professional occupations. Krebs was amongst the numerous Jews who were dismissed from academic posts.

Dismissed from job, Krebs received an offer from Sir Frederick Gowland to work with him at the Department of Biochemistry at the University of Cambridge. He received financial support from Rockfeller Foundation.

In 1934, Krebs was appointed as a Demonstrator in biochemistry. The following year, the University of Sheffield offered him a post of Lecturer in Pharmacology. He retained the post for 19 years.

In 1938, the University of Sheffield opened the Department of Biochemistry of which Krebs served as the first Head and eventually professor in 1945.

It was while at the University of Sheffield that Krebs collaborated with William Johnson. Together, the two investigated cellular respiration by which oxygen was consumed to produce energy from the breakdown of glucose. Using a manometer, they continuously conducted experiments and four months later, finally succeeded in establishing the sequence of the chemical cycle, which they called ‘citric acid cycle’.

In 1953, Hans Adolf Krebs was awarded with Nobel Prize in Physiology or Medicine "for his discovery of the citric acid cycle".

In 1957, Krebs collaborated with Hans Kornberg and found out that there were additional crucial enzymes. They added more details and discovered the glyoxylate cycle which was a modification of the citric acid cycle.

Scientific career apart, Krebs did well academically as well. In 1943, he took over the control over Sorby Research Institute. A year later, he was appointed Director of the newly established MRC Unit for Cell Metabolism Research at Sheffield. In 1954, he moved to the University of Oxford as Whitley Professor of Biochemistry. He held this post until his retirement in 1967. Post retirement, Krebs spent the last two decades of his career researching why organisms oxidized their foodstuffs through such a complex pathway. It was only in 1981 that Jack Baldwin answered his question by stating that acetic acid could not be directly dehydrogenated and required another molecule to complete oxidative decomposition.

Krebs most important contribution in his scientific career came with the discovery of two important chemical reactions in the body, the urea cycle and the citric acid cycle. For the first, he collaborated with Henseleit and discovered the ornithine cycle of urea synthesis, which is often referred to as the Krebs-Henseleit cycle.

The highlight of his career came in 1937 when he discovered the citric acid cycle. It was a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy in the form of guanosine triphosphate (GTP). The discovery earned him Nobel Award in Physiology or Medicine in 1953.

In 1953, Krebs received the prestigious Nobel Prize in Physiology or Medicine for his discovery of the citric acid cycle. He shared the prize with Fritz Lipmann. Same year, he received the Albert Lasker Award for Basic Medical Research.

In 1954, he was bestowed with the Royal Society’s Royal Medal.

In 1958, he received the Gold Medal of the Netherlands Society for Physics, Medical Science and Surgery. Same year, he was knighted.

In 1961, he received the Copley Medal

He was the Original Member of the Society for General Microbiology, which conferred him Honorary Membership in 1980.

Hans Adolf Krebs married Margaret Cicely Fieldhouse on March 22, 1938. The couple was blessed with three children, two sons, Paul and John, and a daughter, Helen

Kerbs breathed his last on November 22, 1981 in Oxford, after suffering from a brief illness.

The University of Oxford named its building of the Department of Biochemistry, Hans Krebs Tower.

In 1988, the University of Sheffield started The Krebs Institute which is a research centre covering interdisciplinary programmes in biochemical research.

In 1990 the Federation of European Biochemical Societies instituted the Sir Hans Krebs Lecture and Medal. The award is given to researchers who have made outstanding achievements in biochemistry and molecular biology.

The Society of Friends of Hannover Medical School gives the Sir Hans Krebs Prize, which is worth 10,000 euros.

The Biochemical Society offers Krebs Memorial Scholarship to a postgraduate student working in biochemistry or an allied biomedical science at any British university.