Theodor Svedberg

For more information on Theodor Svedberg, visit Britannica.com.

Swedish chemist (1884–1971)

Svedberg, born the son of a civil engineer in Fleräng, Sweden, was educated at the University of Uppsala, where he obtained his doctorate in 1908. He spent his whole career at the university, becoming a lecturer in physical chemistry in 1907, a professor (1912–49), and finally, in 1949, director of the Institute of Nuclear Chemistry.

In 1924 he introduced the ultracentrifuge as a technique for investigating the molecular weights of very large molecules. In a suspension of particles, there is a tendency for the particles to settle (under the influence of gravity); this is opposed by Brownian motion, i.e., by collision with molecules. The rate of sedimentation depends on the size and weight of the particles, and can be used to measure these.

Svedberg applied this to measuring the sedimentation of proteins in solution, using an ultracentrifuge that generated forces much greater than that of the Earth's gravitational field. Using this, he could measure the molecular weights of proteins and was able to show that these were much higher than originally thought (hemoglobin, for instance, has a molecular weight of about 68,000).

Apart from confirming the claim made by Hermann Staudinger for the existence of giant molecules, Svedberg's invention also settled one further question. The same protein invariably yielded the same weight thus implying that they did have a definite size and composition and were not, as Wilhelm Ostwald had earlier maintained, irregular assemblies of smaller molecules. For his work on the ultracentrifuge Svedberg was awarded the Nobel Prize for chemistry in 1926.

Svedberg was less successful with the inference he drew from his measurements of protein molecular weights. He thought that the molecular weight of egg albumin formed the basic protein unit of which all the other proteins were multiples. Following later research by crystallographers in the 1930s this view was disproved.

Theodor Svedberg
Born	Theodor H. E. Svedberg 30 August 1884(1884-08-30) Fleräng, Valbo, Gävleborg, Sweden
Died	25 February 1971 (aged 86) Kopparberg, Sweden
Nationality	Sweden
Fields	Biochemistry
Alma mater	Uppsala University
Doctoral students	Arne Tiselius
Known for	analytical ultracentrifugation
Notable awards	Nobel Prize for Chemistry (1926)

Theodor H. E. Svedberg (30 August 1884 – 25 February 1971) was a Swedish chemist and Nobel laureate, active at Uppsala University. His work with colloids supported the theories of Brownian motion put forward by Einstein and the Polish geophysicist Marian Smoluchowski. During this work, he developed the technique of analytical ultracentrifugation, and demonstrated its utility in distinguishing pure proteins one from another.

The unit svedberg (symbol S), a unit of time amounting to 10⁻¹³ s or 100 fs, is named after him.

References

• Stig Claesson; Kai O. Pedersen (1972). "The Svedberg. 1884-1971". Biographical Memoirs of Fellows of the Royal Society 18: 594–627.. doi:10.1098/rsbm.1972.0022. http://links.jstor.org/sici?sici=0080-4606%28197211%2918%3C594%3ATS1%3E2.0.CO%3B2-1. 
• Kyle, R A; Shampo M A (September 1997). "Theodor Svedberg and the ultracentrifuge". Mayo Clin. Proc. 72 (9): 830. PMID 9294529. 

External links

• Svedberg's Nobel Foundation biography

v • d • e Nobel Laureates in Chemistry Theodor Svedberg (1926) · Heinrich Wieland (1927) · Adolf Windaus (1928) · Arthur Harden / Hans von Euler-Chelpin (1929) · Hans Fischer (1930) · Carl Bosch / Friedrich Bergius (1931) · Irving Langmuir (1932) · Harold Urey (1934) · Frédéric Joliot-Curie / Irène Joliot-Curie (1935) · Peter Debye (1936) · Walter Haworth / Paul Karrer (1937) · Richard Kuhn (1938) · Adolf Butenandt / Leopold Ružička (1939) · George de Hevesy (1943) · Otto Hahn (1944) · Artturi Virtanen (1945) · James B. Sumner / John Northrop / Wendell Meredith Stanley (1946) · Robert Robinson (1947) · Arne Tiselius (1948) · William Giauque (1949) · Otto Diels / Kurt Alder (1950) Complete roster · 1901–1925 · 1926–1950 · 1951–1975 · 1976–2000 · 2001–present

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