Obituary: Professor Adolf Butenandt

Adolf Butenandt was one of the leading biochemists of the first half of this century. In 1939 he was awarded the Nobel Prize for Chemistry for his primary achievements - the isolation in the years 1929 to 1934 of the sex hormones oestrone, androst erone and progesterone, and the elucidation of their chemical structure. The Nazi government forbade him from accepting the prize. After the award of the Nobel Prize for Peace to Carl von Ossietzky, who was in a German concentration camp, German citizens were barred by law from accepting Nobel Prizes. It was only after the Second World War that the Swedish Academy asked Butenandt about the circumstances of his refusal. As a result, he received the document and the medal and was listed officially as a No bel prizewinner.

Adolf Butenandt was born in Lehe, near Bremerhaven, in 1903. He studied chemistry and biology in Marburg and Gottingen and did his PhD thesis under the supervision of Adolf Windaus, who was awarded the Nobel Prize in 1928 for his work on sterols. After gaining his DPhil Butenandt remained in Gottingen and started to work on sex hormones. But in 1933, he became Professor of Chemistry at the Danzig Institute of Technology and in 1936 went to Berlin-Dahlem, where he became head of the Kaiser Wilhelm Institute of Biochemistry.

In Dahlem, he began a new project of research: the mechanism of the action of genes. The biologists Ernst Caspari and Alfred Kohn had been working on the eye-colour of insects and discovered that after implantation of tissues from dark-coloured mutants into the larvae of the light-coloured race, these moths developed dark eyes. This could only be explained by the existence of a substance formed under genetic control in the dark race that was responsible for eye pigmentation. Butenandt and his co-workerslooked for this substance and identified it as kynurenine, a metabolite of the amino acid tryptophane. From these experiments, Butenandt concluded in 1940 that "genes act by providing an enzyme system that oxidises tryptophane to kynurene.2". This is inessence the famous "One gene - one enzyme" rule, usually ascribed to George Beadle.

As a result of the air-raids on Berlin during the war, the Kaiser Wilhelm Institute for Biochemistry was transferred in 1944 to Tubingen. There we all witnessed the occupation by French troops and the end of the war. Butenandt became Professor of Physiological Chemistry at the University of Tubingen, and the Kaiser Wilhelm Institute lodged with the Institute of Physiological Chemistry there. Returning to scientific projects, Butenandt took up the isolation of the moulting hormone. It became the first insect hormone to be isolated. I was very much involved in this project, and I will illustrate the methods of hormone research used, in the following example.

Two things are needed; a bioassay with which you measure the biological activity of extracts, and a starting material that contains the hormone. The bioassay we used was puparium formation in ligated blowfly larvae, but it was not easy to rear kilogram quantities. We therefore switched to silkworm pupae. Silkworms are one of the few insect species reared commercially. In 1953, we bought all the silk cocoons we could get hold of. The cocoons were opened in Tubingen and the pupae sorted out into males andfemales. The males were preserved in methanol, the females were allowed to emerge, and their scent glands were then cut off and preserved for the extraction of the sex attractant. We collected 500kg of male pupae from which 5kg of a concentrate were extracted. This was then further reduced, and finally we obtained 25mg of the crystalline hormone, a purification factor of 1:10,000,000. The hormone was named ecdysone. The determination of the structure showed that it was a steroid hormone. Thus, after 20years, Butenandt was back to steroids.

The last big enterprise was the isolation of the sex attractant of the silk moth. Sex attractants are substances produced by the female of the species to lure males for copulation. 500,000 sex glands were needed to yield 12mg of an ester of this substance which was named Bombykol. It was the first pheromone to be isolated.

Looking back over Butenandt's scientific achievements, one can say that he was always a "first". He isolated the first sex hormones, he elucidated the action of genes for the first time, he isolated the first insect hormone and the first pheromone. It goes without saying that he had many co-workers and graduate students who helped him and who should receive appropriate credit. But Butenandt was always the initiator.

In 1960, Butenandt became President of the Max Planck Institute (the new name of the Kaiser Wilhelm Institute). During his time of office, he greatly increased the reputation of the institute. Many new institutes were founded, and many new international links were formed. The annual budget was raised from DM81m to more than DM500m. Butenandt's presidency ended in 1972, but he was then elected Honorary President and for many years still remained active in the Max Planck Institute.

Adolf Friedrich Johann Butenandt, physiological chemist: born Lehe 24 March 1903; scientific assistant, Chemical Institute, Gottingen University 1927-30, lecturer in organic and biological chemistry 1931, leader, organic and biological chemistry laboratories 1931-33; Professor of Chemistry and Director, Organic Chemistry Institute, Danzig Institute of Technology 1933-36; Director, Kaiser Wilhelm Institute of Biochemistry, Berlin-Dahlem (later at Tubingen, now Max Planck Institute of Biochemistry, Munich) 1936-72; Nobel Prize for Chemistry 1939; Professor of Physiological Chemistry, Munich University 1956-71 (Emeritus); President, Max-Planck Society 1960-72; Foreign Member, Royal Society 1968; married 1931 Erika von Ziegner (two sons, five daughters); died 18 January 1995.