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Rihard KunGerman chemist and biochemist
Date of Birth: 03.12.1900
Country:  Germany |
Content:
Biography of Richard Kuhn
Richard Kuhn was a German chemist and biochemist. He was born in Vienna, Austria, to engineer Clements Kuhn and elementary school teacher Angelika (Rodler) Kuhn. Kuhn's early education was led by his mother, and at the age of 9, he entered the gymnasium in Debling, where one of his classmates was Wolfgang Pauli. After completing gymnasium in 1917, Kuhn was drafted into military service and served until the armistice in November 1918. After being discharged from the army, Kuhn enrolled at the University of Vienna, but after three semesters, he transferred to the University of Munich. There, he studied chemistry under Richard Willstatter and in 1922, he earned his doctoral degree for his dissertation on the "Specificity of Enzymes in Carbohydrate Metabolism". Kuhn continued his research at the University of Munich until he received an invitation to work at the Federal Institute of Technology in Zurich in 1926. In 1929, Kuhn left the Federal Institute of Technology and became the head of the chemical division at the newly established Kaiser Wilhelm Institute for Medical Research (later renamed Max Planck Institute) in Heidelberg, while also serving as a professor of chemistry at the university. He became the director of the institute in 1937 and held this position until the end of his career.
Contributions to Biochemistry
Inspired by the work of Willstatter, Kuhn was particularly interested in understanding the relationship between organic chemistry and their functioning in biological systems. Enzymes, the subject of his early research, are protein catalysts that accelerate chemical reactions occurring in cells. Depending on the type, each enzyme specifically reacts with a particular chemical substance (substrate). Kuhn aimed to determine the arrangement of atoms in organic molecules (i.e., their configuration) and investigate how these molecules could deviate the passage of light (i.e., establish their optical isomerism). He also explored conjugated double bonds, a molecular structure in which double and single bonds alternate.
Kuhn combined both areas of his research by studying carotenoids, biological pigments that are important constituents of living cells. The chemical formula of one such substance, carotene, found in carrots, had previously been determined by Willstatter. In 1931, independently from each other, Kuhn and Paul Karrer discovered two distinct components in carotene: alpha-carotene, which deflects light, and beta-carotene, which does not. Two years later, Kuhn discovered a third type - gamma-carotene. These three types (three isomers) have the same chemical formula but differ in molecular configuration, which determines their properties. Kuhn further investigated and found that carotene is a precursor to vitamin A, a necessary "starting material" for the production of this vitamin in biological systems. Vitamin A plays a crucial role in the growth of higher animals and the maintenance of mucous membranes. Additionally, Kuhn discovered that the liver can produce two molecules of vitamin A either from one molecule of beta-carotene or two molecules of alpha-carotene. Kuhn and his colleagues also uncovered the presence of carotenoids in the organisms of many plants and animals, significantly expanding the possibilities of using chromatography as an important analytical tool.
Kuhn then turned his attention to water-soluble B vitamins. Working together with Albert Szent-Györgyi and Julius Wagner-Jauregg, he isolated approximately one gram of lactoflavin from thousands of liters of milk. By determining the structure of lumiflavin, a product of lactoflavin breakdown, Kuhn was able to ascertain the chemical composition of lactoflavin itself and eventually synthesize both compounds. By demonstrating that lactoflavin (now known as riboflavin or vitamin B2) plays an extremely important role in the activity of enzymes involved in the respiratory process, Kuhn made a decisive step in understanding the function of vitamins in living systems. In 1939, Kuhn isolated adermin, now known as vitamin B6, and also determined its chemical composition and molecular structure, which helps regulate the metabolism of the nervous system. In 1939, Kuhn was awarded the Nobel Prize in Chemistry for 1938 "in recognition of his work on carotenoids and vitamins". However, as a German citizen, he was prohibited from accepting the award by the Nazi government. This ban was a result of Adolf Hitler's fury over the Nobel Peace Prize being awarded four years earlier to German political dissident Carl von Ossietzky. Kuhn was only able to receive the Nobel medal and check at a ceremony in Stockholm in 1949.
Continuing his scientific research, Kuhn isolated para-aminobenzoic acid (PABA), a compound used in the synthesis of anesthetic substances and pantothenic acid, which is essential for the formation of hemoglobin and the release of energy from carbohydrates. In 1950, as a professor of biochemistry at the medical faculty of the Max Planck Institute, Kuhn focused his efforts on studying organic substances that contribute to the human body's resistance to infection. His research on influenza viruses, cholera, and Colorado potato beetle larvae made a valuable contribution to understanding the molecular interactions between the human body and its adversaries. Kuhn was characterized as a professional scientist by his precision and perseverance in his work. These qualities were complemented by his creative approach and remarkable intuition. He had a deep interest in the practical application of his findings, especially in agriculture and medicine. Kuhn was also a tennis, chess, and billiards enthusiast, as well as a talented violinist, occasionally performing in public concerts as part of a chamber ensemble. In 1928, he married Daisy Hartmann, and they had four daughters and two sons. The scientist passed away in Heidelberg on July 31, 1967, at the age of 66.
Kuhn was a member of scientific societies in many countries and held honorary degrees from the Technical University of Munich, the University of Vienna, the University of Saint Mary in Brazil, and several others. Two years before his death, he was awarded the first commemorative medal by the University of Heidelberg. Kuhn served as the president of the German Chemical Society and vice-president of the Max Planck Society.
