Northrop, John Howard, 1891–1987, American chemist, b. Yonkers, N.Y., Ph.D. Columbia, 1915. He was a researcher at the Rockefeller Institute for Medical Research (now Rockefeller Univ.) from 1916 until his retirement in 1961. Northrop shared the 1946 Nobel Prize in Chemistry with James Sumner and Wendell Stanley for their work on enzymes. Building on earlier work by Sumner, who had demonstrated that enzymes can be crystallized, Northrop isolated and crystallized a number of biologically important enzymes, including pepsin, trypsin, chymotrypsin, ribonuclease, and deoxyribonuclease, and provided indisputable evidence that they are proteins.