Wendell Stanley shared the Nobel Prize in chemistry in 1946 with John Northrop, awarded to them "for their preparation of enzymes and virus proteins in a pure form," and with James Sumner "for his discovery that enzymes can be crystallized." In 1926 Sumner had crystallized the enzyme urease; in 1930 Northrop had crystallized pepsin; and in 1935 Stanley had crystallized tobacco mosaic virus. Stanley's result and subsequent findings demonstrated that an infectious agent could possess some of the properties of a chemical molecule. Stanley concluded: "Tobacco mosaic virus is regarded as an autocatalytic self-reproducing protein which, for the present, may be assumed to require the presence of living cells for multiplication."
Large batches of tobacco plants infected with tobacco mosaic virus and ground up while frozen were thawed in buffer solution containing alkaline sodium phosphate, and the solution was filtered. The filtrate at lowered pH was treated with concentrated ammonium sulfate. The precipitate contained virus, which was extracted and reprecipitated (by acidification in the presence of 20 percent saturated ammonium sulfate) as small "needles."
Stanley's achievement was soon reproduced in England by Frederick Bawden and Norman Pirie, who were also able to show that the tobacco mosaic virus and other plant viruses contained ribonucleic acid (RNA). Stanley initially considered the RNA to be a contaminant, but later investigations by Seymour Cohen showed RNA to be a very large molecule having a molecular mass of up to 2 million daltons. Surprisingly, the thought that the viral RNA might be the genetic element of the virus was not tested until 1956.
Wendell Meredith Stanley was born in Ridgeville, Indiana, in 1904. On graduation from the University of Illinois in 1926 he aspired to be a football coach. He shortly afterward changed course and embarked on an extremely productive period as a graduate student, with the chemist Roger Adams as his instructor. He received a Ph.D. in chemistry from the University of Illinois in 1929 and stayed there another year, at the end of which he went to work for a year with Heinrich Wieland in Munich. He returned to the United States in 1931, having been given a post at the Rockefeller Institute in New York. In 1932 he moved to the Princeton branch of the institute, where Northrop was also a faculty member. In 1948 he was appointed professor of biochemistry and director of the virus laboratory at the University of California at Berkeley. In 1958 he became a professor of virology. He died suddenly in Spain in 1971, aged sixty-six.
see also Ribonucleic Acid.
Keith L. Manchester
Stanley, Wendell (1935). "Isolation of a Crystalline Protein Possessing the Properties of Tobacco-Mosaic Virus." Science 81: 644–645.
Stanley, Wendell. Nobel Lecture. Available from <http://www.noble.se/chemistry/laureates/1946>.