Hermann Emil Fischer (1852-1919)

Born at Euskirchen, near Bonn, Germany, Hermann Emil Fischer was among the greatest organic chemists of the 19th century. He is most famous for his work on the chemistry of sugars.

Though Fischer was originally destined for the family lumber business, his passion for the natural sciences - and his ineptitude as a businessman - convinced his father that he was better off as a student. Fischer went to the University of Bonn in 1871 to study chemistry, but attended many physics lectures as this was his preferred subject. In 1872 his cousin Otto persuaded him to go to the University of Strasbourg. It was there, working under Adolf von Baeyer, that Fischer decided to devote his life to chemistry. At Strasbourg, Fischer worked on phthaleins, a group of synthetic dyes.

He followed von Baeyer to Munich in 1875, qualifying as a Privatdocent in 1878. In 1881 he was appointed Professor of Chemistry at the University of Erlangen, and started studying caffeine and theobromine - the active ingredients in tea, coffee and cocoa. The following year he began his work on sugars and purines. He continued this work at the University of Würzburg, where he became a professor in 1888, and at the University of Berlin, where he was appointed in 1892 and remained until his death.

Fischer established that organic substances including adenine, xanthene, caffeine, uric acid and guanine all belong to the same family. He hypothesised about the nature of the parent substance, which he called purine, and synthesised it in 1898.

Fischer’s study of the sugars enabled him to discover the relationship between glucose and fructose, and he synthesised these sugars in 1890. He went on to establish the arrangement in space (known as the absolute configuration) of the 16 aldohexose sugars (including D-glucose) in 1892. He was awarded a Nobel Prize in 1902 for this work on sugars and purines.

For almost a decade from 1899, Fischer also worked on proteins. He analysed and identified the amino acids, discovering several new ones in the process, and established the nature of the bond that holds them together - the peptide bond. He also studied enzymes, proposing the analogy of a lock and key to explain the specificity of enzyme action. This model now underpins much of modern biochemistry and pharmacology. In the final years of his life he also studied the fats.