John Howard Northrop (July 5, 1891 – May 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.
Northrop was born in Yonkers, New York and 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 Wickenberg, Arizona.
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