Hans Adolf Krebs

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.

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 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.

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.