John Howard Northrop

John Howard Northrop (July 5, 1891May 27, 1987) was an American biochemist who won the Nobel Prize in Chemistry in 1946 (with James Batcheller Sumner and Wendell Meredith Stanley) for purifying and crystallizing certain enzymes.

Early life

Northrop was born in Yonkers, New York. His father, a trained zoologist, died in a lab explosion two weeks before John was born. He 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.


In 1929, he isolated and crystallized the gastric enzyme pepsin and determined that it was a protein and 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. Northrop died in Wickenburg, Arizona.

His daughter Alice married Frederick C. Robbins, who was awarded Nobel Prize in Physiology or Medicine in 1954.

Later life

John Howard Northrop committed suicide May 27, 1987.


* Shampo, M A & Kyle, R A (2000), "John Northrop--definitive study of enzymes.", Mayo Clin. Proc. 75 (3): 254, 2000 Mar, PMID:10725951, <>

* Herriott, R M (1994), "John Howard Northrop: July 5, 1891-May 27, 1987.", Biographical memoirs. National Academy of Sciences (U.S.) 63: 423-50, 1994, PMID:11615389, <>

* 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 Nov, PMID:11616207, <>

* Herriott, R M (1981), "John Howard Northrop.", J. Gen. Physiol. 77 (6): 597-9, 1981 Jun, PMID:7021760, <>

* 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, PMID:3908838

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