Hans Krebs( German-British biochemist, Nobel Prize in Physiology or Medicine, 1953)
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Biography Hans Krebs
August 25, 1900, Mr.. - November 22, 1981
German-British biochemist Hans Adolf Krebs was born in Hildesheim (Germany), the son of Georg Krebs otolaryngologist and Alma Krebs (David-son). Primary education he received in Andreanum-Gymnasium in Hildesheim. In 1918, Mr.. K. graduated from high school. In the last months of World War I he served in the regiment of the Prussian army communications. Then K. studied medicine in Gц╤ttingen, Freiburg, Munich and Berlin universities, and in 1925. received a medical degree at the University of Hamburg. He further during the year studied chemistry at the Institute of Pathology University of Berlin, and then began working as a laboratory assistant at the Otto Warburg at the Kaiser Wilhelm Institute for Biology in Berlin.
. Warburg has developed an experimental method for studying cellular respiration - oxygen consumption and allocation of carbon dioxide in the metabolism of carbohydrates, fats and proteins
. Instead of studying respiration in intact animals or explore the whole organs, Warburg began to use thin slices of fresh tissue, placed in an airtight container with a pressure sensor. When in the process of biochemical reactions tissues absorb the oxygen pressure in the vessel decreased, and this served as an objective indicator of respiratory activity.
In 1930. K. again engaged in clinical medicine and began working as an assistant in a municipal hospital in Altona (Hamburg) and Assistant Professor (Visiting Professor) in the medical clinic, University of Freiburg. At the same time, he continued biochemical studies. Using an experimental system similar to the installation Warburg, he described the cycle mochevinoobrazovaniya - the process whereby the body removes the end products of nitrogen metabolism. He found that the amino acid ornithine, added to liver slices, plays a catalytic role in this series, ie. accelerates the synthesis of urea, but itself when it is not consumed. It was found that ornithine into a similar amino acid citrulline, which in turn passes into the amino acid arginine. Arginine cleaved to urea and ornithine, and the whole cycle repeats itself, first. Developing the concept of cyclic processes in biochemistry brought to. world fame.
When in 1933. to power in Germany, Hitler came, K., who is Jewish, lost his job at the University of Freiburg. However, Rockefeller Research Society gave him the opportunity to study biochemistry under the guidance of Frederick Goulenda Hopkins Institute of Biochemistry, University of Cambridge in the UK. In 1933. K. arrived in Cambridge, did not bring 'practically nothing except a sigh of relief, several books and 16 packages of vessels Warburg'. He began working demonstrator, a biochemist and soon received a master's degree. In 1935. He was appointed professor of pharmacology at Sheffield University. The following year, the scientist and Zionist leader Chaim Weizmann invited to. to the Institute of Biochemistry of the Jewish University, which at that time was created in Rehovot (Palestine). However, although. and fascinated by the idea of pioneer life, especially in the kibbutzim (collective farms), opportunities for research in Jewish University were very limited and, moreover, again broke the Arab-Israeli conflict. Therefore K. decided to stay in England, where he was appointed professor by the hour, Department of Biochemistry University of Sheffield.
In 1937, studying the intermediate stages of carbohydrate metabolism, K. made a second important discovery in biochemistry. He described the citric acid cycle or tricarboxylic acid cycle, which is now called the Krebs cycle. This cycle represents the final common path decomposition of carbohydrates, proteins and fats to carbon dioxide and water and is the main source of energy for most living organisms. In earlier studies of Albert Szent-Gyorgyi, . Franz Knoop, . Charles Martiusa and other researchers have shown, . that in the presence of oxygen citric acid (hexatomic tricarboxylic acid) as a result of successive reactions converted into oxaloacetic acid (chetyrehatomnuyu tricarboxylic acid) and carbon dioxide.,
. Presentation of the Krebs cycle allows us to understand how out of nutrients in the body produces energy
. K. studied the sequence of transformations of energy in the body of nutrients, in order to determine how the carbohydrates pass into other compounds. Analyzing the formula for more than 20 organic acids, similar to carbohydrates, K. convinced that the lactic and pyruvic acids can themselves undergo a sequence of transformations. Eventually he began his experiments using pyruvic acid.
To. by experimentation proved that the oxidation of pyruvic acid forms an intermediate compound - atsetilkoenzim A. (Coenzyme, . or coenzyme, . - Is an integral part of the enzyme, . necessary for its catalytic activity.) addition, . He opened, . that this oxidation produces carbon dioxide and other acids are formed, the whole process continues to engage the next molecule of coenzyme AK,
. found that the basic principles of its cycle are also valid for other nutrients, in particular for fatty acids.
Opening of the cyclic principle of intermediate exchange reactions was a milestone in the development of biochemistry, t. to. gave the key to understanding the metabolic pathways. In addition, it has stimulated other experimental work and the representation of the sequence of cellular reactions.
In 1939, Mr.. K. granted British citizenship. During the Second World War, he conducted studies of the British Medical Research Council on Nutrition, in t.ch. concerning the needs for vitamins A and C. In 1945, Mr.. K. was appointed professor and head of the Department of Biochemistry and Director of the Medical Research Council of cellular metabolism at Sheffield University.
In 1953, Mr.. K. was awarded the Nobel Prize in Physiology or Medicine "for his discovery of the citric acid cycle '. K. shared the prize with Fritz Lippmann. In the congratulatory speech researcher at the Karolinska Institute, Eric Hammarsten said: 'Krebs cycle explains the two simultaneously occurring processes: decomposition reaction, . in which energy is released, . and synthetic processes, . in which this energy is spent ',
. In his Nobel lecture to. summarized their findings in the citric acid cycle. Concluding speech 'excursion into the general biology', he analyzed the broader significance of these findings. 'The presence of one and the same formation mechanism of energy in all living beings can make two conclusions - he said. - Firstly, this mechanism has arisen in the very early stages of evolution, and, secondly, the life in its present form arose only once '.
A year after receiving the Nobel Prize to. was appointed Professor of Biochemistry, Nuffield Department of Clinical Medicine at Oxford University, where relocated Medical Research Council of cellular metabolism. Three years later, K. with his former pupil Hans Kornberg discovered a variety of citric acid cycle - a cycle glioksilata, in which two molecules of coenzyme A are converted into suktsinilovuyu acid. This cycle is more important for the metabolic processes in plant and microbial, rather than animal cells. K. and Kornberg worked together on the difficulty 'of energy transformation in living matter (review)' ( 'Energy Transformation in Living Matter: A Survey', 1957), which examined the citric acid cycle and its function in living organisms.
. After his retirement from Oxford University in 1967
. K. appointed consulting professor of Biochemistry at the Royal Free Hospital Medical School. He continued research on the regulation of the rate of exchange reactions, 'inborn errors of metabolism' and preservation for liver transplantation in the Nuffield Department of Clinical Medicine, University of Oxford. K. critical of 'expensive and unproductive' university research and government policy.
. He once likened his attempts to explain the chemical processes occurring in living cells, with the search for the missing puzzle-pieces puzzle.
. In 1938
. K. married Margaret Saysli Fildhauz. In the family they had two sons and a daughter. November 22, 1981, Mr.. K. died in Oxford at the age of 81.
To. been awarded many prizes, t.ch. Lasker Award of the American Public Health Association (1953), the Royal medal (1954) and the Copley medal (1961), the Royal Society, as well as the gold medal of the Royal Society of Medicine (1965). In 1958, Mr.. K. Queen Elizabeth II was awarded a title of nobility. He was a foreign member of the American Academy of Arts and Sciences and the American National Academy of Sciences. In addition, he was a member of the American College of Physicians and a member of the Weizmann Institute (Israel).