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. He had been left-handed before the accident, after which he had to learn to do things with his right hand.[5]
Sumner married Cid Ricketts (born Bertha Louise Ricketts in Brookhaven, Mississippi) when she attended medical school at Cornell. They married on July 10, 1915, and had four children.[6] They were divorced in 1930, but she kept her married name.Cid Ricketts Sumner went on to become an author, writing books that includedTammy Tell Me True, which was made into the movieTammy and the Bachelor, andQuality, which became the moviePinky. Cid Ricketts Sumner was murdered by their grandson, John R. Cutler, in 1970.
In 1931 Sumner married Agnes Lundkvist. In 1943 they divorced; later that year he married Mary Beyer, with whom he had two children.[4]
It was in 1917 at Cornell where Sumner began his research into isolatingenzymes in pure form; a feat which had never been achieved before.[4] The enzyme he worked with wasurease, which he isolated fromjack beans. 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 demonstrated that urease could be isolated andcrystallized. He accomplished this by mixing purified urease withacetone and then chilling it; the chilled solution produced crystallized urease.[4] He was also able to show by chemical tests that his pure urease was aprotein.[7] This was the first experimental proof that an enzyme is a protein, a controversial question at the time.
His successful research brought him to full professorship at Cornell in 1929. From 1924 on his laboratory was located on the second floor of the new dairy science building, Stocking Hall (today home to Food Science), at Cornell where he did his Nobel Prize–winning research. In 1937 he succeeded in isolating and crystallizing a second enzyme,catalase. By this time,John Howard Northrop of theRockefeller Institute had obtained other crystalline enzymes by similar methods, starting withpepsin in 1929. It had become clear that Sumner had devised a general crystallization method for enzymes, and also that all enzymes are proteins.
