Euler-Chelpin, Hans Karl August Simon von

(b. Augsburg, Germany, 15 February 1873; d. Stockholm, Sweden, 6 November 1964)

biochemistry.

Hans von Euler-Chelpin was the son of Rigas von Euler-Chelpin, a captain in the Royal Bavarian Regiment, and Gabrielle Furtner and was of the same family lineage as the Swiss mathematician Leonhard Euler. He attended schools in Munich, Würzburg, and Ulm, then from 1891 to 1893 studied art at the Munich Academy of Painting. His concern with the theory of colors caused him to become interested in the spectrum, and he turned his attention to science.

Euler-Chelpin enrolled at the then University of Berlin, where he studied physics under Emil Warburg and Max Planck and organic chemistry under Emil Fischer and A.Rosenheim. During the next two years he worked with W. Nernst in Göttingen. In the summer of 1897 he became an assistant to Svante Arrhenius in Stockholm, where he qualified as Privatdozent in physical chemistry at the University of Stockholm in 1898; he spent the summers of 1899 and 1900 with J. H. van’t Hoff in Berlin.

Until this time Euler-Chelpin had concentrated on physical chemistry, a subject being developed with much enthusiasm in Germany and Sweden. He now turned toward organic chemistry, visiting the laboratories of Arthur Hantzsch at Würzburg and Leipzig and Johannes Thiele at Strasbourg. He began research in the field at this time, partly in collaboration with his wife, Astrid Cleve. His visits to the laboratories of E. Buchner in Berlin and G. Bertrand in Paris reflected a developing interest in fermentation.

He became professor of general and organic chemistry at the University of Stockholm in 1906. All of his remaining professional work was carried out in Sweden, of which country he became a citizen in 1902. Nevertheless, in World War I he reported for service in the German army, serving in the artillery and, after 1915, in the air force. In the winter of 1916–1917 he was assigned to a military mission in Turkey to stimulate production of munitions and alcohol. He then returned to the air force, where he became commander of a bomber squadron. During this period he had an arrangement with the University of Stockholm that permitted him to compress his teaching activities into a half year. During World War II Euler-Chelpin again made himself available to Germany, but in a diplomatic capacity.

In 1929, the year in which he shared the Nobel Prize in chemistry with Arthur Harden for studies on fermentation, Euler-Chelpin became director of the Vitamin Institute and Institute of Biochemistry founded at the University of Stockholm through the joint support of the Kurt and Alice Wallenburg Foundation and the International Education Board of the Rockefeller Foundation. In 1941 he retired from teaching but continued his research activities almost to the end of his life. He was twice married: to Astrid Cleve (1902–1912), daughter of P. T. Cleve, professor of chemistry at the University of Uppsala, by whom he had five children; and Elisabeth, Baroness Ugglas (1913–1964), by whom he had four children. Both women were associated with him in some of his investigations. His son Ulf Svante von Euler shared the Nobel Prize in medicine or physiology in 1970.

Euler-Chelpin’s early interest in inorganic catalysis was soon transferred to biochemical studies and particularly to the enzymes associated with fermentation. His studies on the chemistry of plants led him to concentrate his interest on those fungi that lend themselves to the study of metabolic problems. His studies on vitamins were not really a diversion; most of this work contributed to the understanding of enzyme cofactors. His late work on cancer was also an extension of his work on enzymes.

The work for which Euler-Chelpin received the Nobel Prize in 1929 was closely associated with Buchner’s discovery that cell-free yeast juice was still able to ferment sugar, and the observation by Harden and Young that such juice, when passed through an ultrafilter, was separated into two fractions, neither of which alone had the power to ferment sugar but which on mixing again showed normal fermenting activity. Euler-Chelpin studied the low molecularweight fraction—named cozymase—for more than a decade, starting in 1923. By 1929 he and his associates, particularly K. Myrbäck and R. Nilsson, had clarified the role of cozymase in fermentation.

Harden had shown that phosphoric acid played a role in fermentation by giving rise to certain sugar phosphates. Euler-Chelpin and Nilsson developed the use of inhibitors whereby certain stages in enzymecatalyzed reactions can be blocked by use of a toxic substance, using fluoride to block that phase of fermentation in which cozymase functions. With Myrbäck, Euler-Chelpin showed that when glucose reacts with phosphoric acid it splits into two threecarbon fragments, one of which remains combined with phosphate. The two other fragments then combine to form glucose diphosphate, while the non-phosphorylated fragment undergoes further degradation. The reaction thereby shows that the sugar molecule undergoing fermentation splits into an energy-rich and an energy-poor fragment.

Euler-Chelpin also investigated the chemical nature of cozymase. Although cozymase is widely distributed in the plant and animal world, Euler-Chelpin and his associates found yeast to be the most practical source for its preparation. Starting with a crude extract having 200 units of activity, they concentrated this into a product having a specific activity of 85,000 units. This product corresponded to a nucleotide, containing sugar, a purine base, and a phosphate; it was clearly related to adenylic acid, which had been isolated by others from muscle. When Warburg showed nicotinamide to be a cofactor in erythrocytes, Euler-Chelpin tested for nicotinamide in cozymase with positive results. Soon thereafter Euler-Chelpin, Fritz Schlenk, and their co-workers showed the chemical structure of cozymase to be that of diphos phopyridine nucleotide (DPN).

In his work on vitamins, Euler-Chelpin assisted in clarifying the role of nicotinamide and thiamine (B₁) in metabolically active compounds. Somewhat earlier, in association with the Swiss chemist Paul Karrer, he had helped clarify the vitamin A activity of the carotenoid pigments. His work on tumors dealt particularly with the role of nucleic acids.

BIBLIOGRAPHY

I. Original Works.There is no collected bibliography of Euler-Chelpin’s more than 1,100 research papers, but see the listings in Poggendorff and in the author indexes of Chemical Abstracts. His Nobel Prize lecture, “Fermentation of Sugars and Fermentative Enzymes,” is available in Nobel Lectures, Including Presentation Speeches and Laureates’ Biographies, Chemistry, 1922–1941 (Amsterdam, 1966), pp. 144–155. His work is dealt with in detail in his books Grundlagen und Ergebnisse der Pflanzenchemie, 3 vols. (Brunswick, 1908–1909); Chemie der Hefe und der alkoholischen Gärung (Leipzig, 1915); Chemie der Enzym, 2 vols. (Munich-Wiesbaden, 1920–1927); Biokatalysatoren (Stuttgart, 1930); Homogene Katalyse (Stuttgart, 1931); Biochemie der Tumoren (Stuttgart, 1942), written with B. Skarzynski; Reductone, ihre chemischen Eigenschaften und biochemischen Wirkungen (Stuttgart, 1950); and Chemotherapie und Prophylaxe des Krebses (Stuttgart, 1962).

II. Secondary Literature. The best biographical sketch is Feodor Lynen’s obituary “Hans von Euler-Chelpin,” in Bayerische Akademie der Wissenschaften, Jahrbuch (1965), pp. 206–212. Also see R. Lepsius, “Hans Karl August von Euler-Chelpin zum Gedächtnis,” in Chemikerzeitung, 88 (1964), 933–936. Memoirs on his eightieth birthday are B. Eistert, “Hans von Euler-Chelpin zum 80 Geburtstag,” ibid., 77 (1953), 65; and W. Franke, “Zu Hans von Euler’s 80 Geburtstag,” in Naturwissen schaften, 40 (1953), 177–180. Also see the sketch accompanying his lecture in Nobel Lectures, pp. 156–158.

Aaron J. Ihde