FISCHER, EMIL

born Oct. 9, 1852, Euskirchen, Prussia died July 15, 1919, Berlin, Ger. Emil Fischer. in full Emil Hermann Fischer German chemist who was awarded the Nobel Prize for Chemistry in 1902 in recognition of his investigations of the sugar and purine groups of substances. Educated at the universities of Bonn and Strasbourg (Ph.D., 1874), Fischer held several posts before becoming professor of chemistry at the University of Berlin in 1892. Under his direction, the chemical laboratory at Berlin became one of the most important in the world and attracted to itself a constant stream of brilliant pupils. During World War I Fischer was responsible for organizing the production of chemicals in Germany. He committed suicide in 1919, after two of his sons had been killed in the war. Fischer's research on the purines was instituted in 1881. He determined the structures of uric acid, xanthine, caffeine, theobromine, and other related compounds, and he showed that they are all derivatives of a single compound, a nitrogenous base that he named purine. His researches into the sugar group, begun in 1883, were of unparalleled importance to organic chemistry. In 1875 he had published his discovery of the compound phenylhydrazine, a substance that in 1884 he found reacts with simple sugars to form derivatives called osazones. Despite major complications because of stereochemical relations, Fischer was able to use these derivatives to determine the molecular structures of fructose, glucose, and many other sugars, and he was able to verify his results by synthesizing those compounds. He also showed how to distinguish the formulas of the 16 stereoisometric glucoses. In the course of his stereochemical research, Fischer discovered that there are two series of sugars, the D sugars and the L sugars, that are mirror images of each other. His study of sugars led him to investigate the reactions and substances involved in fermentation, and, in his investigations of how enzymes break down sugars, Fischer laid the foundations for enzyme chemistry. Fischer's researches on the purines, begun in 1894, culminated in his pioneering efforts to determine the structure of proteins. It was already known that proteins were composed of amino acids, but Fischer found new ways of purifying amino acids and determining how they are combined together within the protein molecule. He then found ways to link amino acids to each other and began synthesizing proteinlike substances; in 1907 he was able to combine 18 amino acids into a polypeptide, which he then broke down by enzymes in the same manner as would occur in a natural protein.