John (Howard) Northrop

Biochemist, born in Yonkers, New York, USA. He spent most of his career pursuing viral and enzyme research at the Rockefeller Institute (later university) (1924–61), with time also spent as professor of bacteriology at the University of California, Berkeley (1949–58). During the 1930s, he and his colleagues isolated the enzymes trypsin and chymotrypsin. In 1939 he was the first to isolate a bacterial virus, and in 1940 he crystallized diphtheria antitoxin. He shared the Nobel Prize for Chemistry in 1946.

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.

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.