Sumner graduated from Harvard University with a bachelor's degree in 1910 where he was acquainted with prominent chemists Roger Adams, Farrington Daniels, Frank C. Whitmore, James Bryant Conant and Charles Loring Jackson. In 1912, he went to study biochemistry in Harvard Medical School and obtained his Ph.D. degree in 1914 with Otto Folin. He then worked as Assistant Professor of Biochemistry at the Weill Medical College of Cornell University.
It was at Cornell where Sumner began his research into isolating enzymes in pure form; a feat which had never been achieved before. The enzyme he worked with was urease. Sumner's work was unsuccessful for many years and many of his colleagues were doubtful, believing that what he was trying to achieve was impossible, but in 1926 he discovered that even low molecular weight enzymes could be isolated and crystallized. His successful research brought him to full professorship in 1929.
In 1937, he was given a Guggenheim Fellowship and he spent five months in Sweden working with Professor Theodor Svedberg. Also that year, John Howard Northrop of the Rockefeller Institute obtained crystalline pepsin making it clear that Sumner had devised a general crystallization method for enzymes and he was awarded the Scheele Medal in Stockholm.
Both Sumner and Northrop shared the Nobel Prize in 1946 for crystallization of enzymes. Sumner was elected to the National Academy of Science in 1948. Sumner died aged 67 of cancer on August 12 1955.
While hunting at age 17, Sumner was accidentally shot by a companion and as a result his left arm had to be amputated just below the elbow.
* ALEXANDER L. DOUNCE (1955). "Prof. James B. Sumner". Redox Report 176 (4488): 859. doi:10.1038/176859a0.
* "Sumner, James B. (1887-1955)" . Biographical Memoirs / National Academy of Sciences 31.