John Howard Northrop was a pioneering American biochemist whose groundbreaking work fundamentally transformed biochemical understanding of enzymes and viral structures. Born in Yonkers, New York on July 5, 1891, he earned his Bachelor of Science, Master of Arts, and Ph.D. in chemistry from Columbia University, completing his doctorate in 1915. He began his distinguished research career at the Rockefeller Institute for Medical Research in 1916, where he served as Associate, Associate Member, and ultimately Member before his retirement in 1961. During World War I, he served as a Captain in the Chemical Warfare Service while conducting research on fermentation processes for industrial production of acetone and ethyl alcohol. Following his retirement from Rockefeller, he joined the University of California, Berkeley as Professor of Bacteriology and later Professor of Biophysics, continuing his scientific contributions until his passing.
Northrop's most significant scientific achievement came in 1929 when he successfully isolated and crystallized pepsin, a digestive enzyme found in gastric juice, demonstrating conclusively that enzymes are proteins rather than some other type of molecule. This groundbreaking work resolved a longstanding debate in biochemistry about the chemical nature of enzymes and established the foundation for modern enzymology, earning him election to the United States National Academy of Sciences in 1934. Building on this success, he developed crystallization techniques that enabled him to isolate and characterize numerous other enzymes including pepsinogen, trypsin, chymotrypsin, and carboxypeptidase, further solidifying the protein nature of enzymatic activity. In 1938, he extended his expertise to virology by isolating and crystallizing the first bacteriophage, demonstrating that viruses are nucleoproteins composed of both nucleic acid and protein, a discovery that profoundly influenced the emerging field of molecular biology.
For his transformative contributions to biochemistry, Northrop was awarded the Nobel Prize in Chemistry in 1946, sharing the honor with James Batcheller Sumner and Wendell Meredith Stanley for their collective work on the isolation, crystallization, and study of enzymes, proteins, and viruses. His influential 1939 book Crystalline Enzymes: The Chemistry of Pepsin, Trypsin, and Bacteriophage became a seminal text in the field and earned him the Daniel Giraud Elliot Medal from the National Academy of Sciences. Throughout his career, he received numerous prestigious honors including election to the American Philosophical Society in 1938 and fellowship in the American Academy of Arts and Sciences in 1949. His rigorous methodologies for enzyme crystallization became standard techniques that enabled subsequent generations of biochemists to study protein structure and function, establishing him as a foundational figure in the development of molecular biology whose work continues to inform contemporary research in enzymology and virology.
