John Howard Northrop

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American chemist (1891–1987)

The son of biologists, Northrop was born in Yonkers, New York, and educated at Columbia, obtaining his PhD there in 1915. In 1917 he joined the Rockefeller Institute of Medical Research, only leaving on his retirement in 1961.

In the early 1930s Northrop confirmed some earlier results of James Sumner. Between 1930 and 1935 he and his coworkers succeeded in isolating a number of enzymes, including pepsin, trypsin, chymotrypsin, ribonuclease, and deoxyribonuclease, crystallizing them and exhibiting unequivocally their protein nature. This was sufficient finally to convince chemists that Sumner was correct, and Richard Willstätter had been wrong in his assertion that enzymes are nonprotein.

Using Northrop's techniques, Wendell Stanley was able in 1936 to isolate and crystallize the tobacco mosaic virus, and showed it to be composed of nucleoprotein. Subsequently (1938) Northrop isolated a bacteriophage (bacterial virus) and demonstrated that this also consisted of nucleoprotein. For such work on the isolation and crystallization of proteins and viruses, Northrop, Sumner, and Stanley shared the 1946 Nobel Prize for chemistry.

The Nobel Prize-winning American biological chemist John Howard Northrop (1891-1987) established that enzymes are proteins and also showed that a bacterial virus is a nucleic acid-protein complex.

On July 5, 1891, J. H. Northrop was born in Yonkers, NY. He attended Columbia University, majoring in chemistry and earning a bachelor of science degree in 1912 and a masters degree in science in 1913. He studied the nature of phosphorus in starch for his thesis research and received a doctoral degree in chemistry in 1915. Northrop accepted a position with the biologist Jacques Loeb at the Rockefeller Institute for Medical Research in New York City.

Early Research

In his early career, Northrop was concerned with the effect of environmental factors on the hereditary properties of fruit flies (Drosophila). He began by growing the flies aseptically, without pathological microorganisms. It was probably the first time animals had been cultivated free of microorganisms. Northrop found that although carbon dioxide output, a measure of energy expended, was greater at 15°C than at 22°C, the flies lived longer at 15°C than at 22°C. This discovery exploded the existing hypothesis that life duration was regulated by an energy limit.

The entrance of the United States into World War I cut short Northrop's fruit fly research. His talents were needed by the Federal government to produce acetone for the war effort. He was commissioned a captain in the Army's chemical warfare service. In a short time Northrup developed a method of fermentation of potatoes which produced substantial quantities of acetone.

Work on Enzymes

After the war Northrop returned to the Rockefeller Institute and began studying enzymes. He first tried to determine the conditions which affect the action of the digestive enzymes pepsin and trypsin. By 1929 he had obtained crystals of swine pepsin, but it was not until 1931 that his failure of any of his methods to separate the enzymatic activity from the proteinous material finally convinced him that pepsin must be protein - another significant discovery.

Work on Viruses

Throughout his career Northrop had an interest in self-duplicating systems, one of the prime characteristics of living units. This interest led him to examine, in the 1920s, the way in which tobacco mosaic virus and bacterial viruses (bacteriophages) reproduce. These studies prepared him for work in the late 1930s in which he showed that highly purified staphylococcus bacteriophages contained nucleic acid as well as protein. This was one of the earliest demonstrations of the presence of nucleic acid in virus. Later he drew attention to the possibility that the nucleic acid in bacterial viruses might correspond to the free deoxyribonucleic acid (DNA) of the transforming principle, which in the virus is encased in a protein unit that serves to protect the DNA and to introduce it into the susceptible cell.

Recognition of Achievements

Northrop became a full member of the Rockefeller Institute for Medical Research (now Rockefeller University) in 1923, after Loeb's death. He retained that position throughout his life. He was elected to membership in the National Academy of Sciences in 1934. He shared the Nobel Prize in chemistry in 1946 with his Rockefeller colleague Wendell F. Stanley and with Cornell University's James B. Summer for their work on purification and crystallization of enzymes.

After the closing of the Rockefeller Laboratories in Princeton, New Jersey, Northrop moved to Berkeley, California. There he became a professor of bacteriology and biophysics at the University of California at Berkeley, and he continued to work on mechanisms by which viruses arise in apparently healthy cells. He served as a contributing editor of the Journal of General Physiology, beginning in 1925.

Northrop died at his home in Wickenberg, Arizona, on May 27, 1987, after a long retirement. His son-in-law, Frederick Robbins, was also a Nobel Prize recipient, capturing the 1954 award in physiology and medicine.

Further Reading

Most of Northrop's research papers were published in the Journal of General Physiology; he also wrote a book, Crystalline Enzymes (1939; rev. ed. 1948); The Nobel Foundation's Chemistry (3 vols., 1964-1966) contains a biography of Northrop; Information on Northrop and his work is also found in Eduard Farber, ed., Nobel Prize Winners in Chemistry, 1901-1950 (1953); and in Paula McGuire, ed., Nobel Prize Winners (1992).

John Howard Northrop
Born	July 5, 1891(1891-07-05) Yonkers, New York, USA
Died	May 27, 1987 (aged 95) Wickenburg, Arizona, USA
Nationality	United States
Fields	Biochemistry
Institutions	Columbia University Rockefeller University
Alma mater	Columbia University
Doctoral advisor	Jacques Loeb
Known for	Studies of enzymes
Notable awards	Nobel Prize in Chemistry (1946)

John Howard Northrop (July 5, 1891 – May 27, 1987) was an American biochemist who won, with James Batcheller Sumner and Wendell Meredith Stanley, the 1946 Nobel Prize in Chemistry. The award was given for these scientists' isolation, crystallization, and study of enzymes, proteins, and viruses.^[1]

Contents 1 Biography 1.1 Early years 1.2 Research 1.3 Personal life 2 References 3 Further reading 4 External links

Biography

Early years

Northrop was born in Yonkers, New York to John I., a zoologist and instructor at Columbia University, and Alice R. Northrop, a teacher of botany at Hunter College. His father died in a lab explosion two weeks before John H. Northrop was born. The son was educated at Columbia University, where he earned his PhD in chemistry in 1915. During World War I, he conducted research for the U.S. Army Chemical Warfare Service on the production of acetone and ethanol through fermentation. This work led to studying enzymes.

Research

In 1929, Northrop isolated and crystallized the gastric enzyme pepsin^[2] and determined that it was a protein. In 1938 he isolated and crystallized the first bacteriophage (a small virus that attacks bacteria), and determined that it was a nucleoprotein. Northrop also isolated and crystallized pepsinogen (the precursor to pepsin), trypsin, chymotrypsin, and carboxypeptidase.

His 1939 book, Crystalline Enzymes, was an important text. Northrop was employed by the Rockefeller Institute for Medical Research in New York City from 1916 to 1961, at which time he retired.

Personal life

In 1917, Northrop married Louise Walker, with whom he had two children: John, an oceanographer, and Alice, who married Nobel laureate Frederick C. Robbins. Northrop committed suicide in Wickenberg, Arizona in 1987.^[3]

References

1. ^ "The Nobel Prize in Chemistry 1946 - Preparing Pure Proteins". http://nobelprize.org/nobel_prizes/chemistry/laureates/1946/speedread.html. Retrieved 2008-12-14. 
2. ^ Northrop, J. H. (1929), "Crystalline Pepsin", Science 69: 580, doi:10.1126/science.69.1796.580 
3. ^ See p. 440 of Herriott, R. M. (1994), "John Howard Northrop: July 5, 1891-May 27, 1987", Biographical Memoirs. National Academy of Sciences (U.S.) 63: 423–50, http://www.nap.edu/openbook.php?record_id=4560&page=423 

Further reading

• Economos, A. C.; Lints, F. A. (1985), "Growth rate and life span in Drosophila V. The effect of prolongation of the period of growth on the total duration of life (J.H. Northrop, 1917)--revisited", Mech. Ageing Dev. 33 (1): 103–13, 1985 Dec, doi:10.1016/0047-6374(85)90112-5, PMID 3908838 
• Herriott, R. M. (1981), "John Howard Northrop", J. Gen. Physiol. 77 (6): 597–9, 1981 Jun, doi:10.1085/jgp.77.6.597, PMID 7021760 
• Herriott, R. M. (1994), "John Howard Northrop: July 5, 1891-May 27, 1987", Biographical Memoirs. National Academy of Sciences (U.S.) 63: 423–50, PMID 11615389, http://www.nap.edu/openbook.php?record_id=4560&page=423 

* See also this version of Northrop's National Academy of Science biography.

• Northrop, J. H. (1939), Crystalline Enzymes, Columbia University Press 
• Shampo, M A; Kyle, R. A. (2000), "John Northrop--definitive study of enzymes", Mayo Clin. Proc. 75 (3): 254, 2000 March, PMID 10725951 
• van Helvoort, T. (1992), "The controversy between John H. Northrop and Max Delbrück on the formation of bacteriophage: bacterial synthesis or autonomous multiplication?", Annals of Science 49 (6): 545–75, 1992 November, doi:10.1080/00033799200200451, PMID 11616207 

External links

• Northrop's Nobel Foundation biography
• Northrop's Nobel Lecture The Preparation of Pure Enzymes and Virus Proteins

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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