James B. Sumner

James B. Sumner was an American biochemist who made a foundational discovery in the field of enzymology. He is best known for being the first scientist to crystallize an enzyme, proving these biological catalysts were proteins. For this groundbreaking work, he was awarded the Nobel Prize in Chemistry in 1946, sharing the honor with John Howard Northrop and Wendell Meredith Stanley. His research provided critical evidence in the debate over the chemical nature of enzymes and paved the way for modern structural biology.

Early life and education

James Batcheller Sumner was born in Canton, Massachusetts. A childhood hunting accident resulted in the amputation of his left arm below the elbow, an event that profoundly shaped his determination. He pursued his undergraduate studies at Harvard University, initially in electrical engineering before switching to chemistry. After graduation, he worked briefly in his family's cotton mill operation and taught at Mount Allison College in Sackville, New Brunswick. He returned to Harvard University for graduate work in biochemistry under the guidance of Otto Folin, earning his Ph.D. in 1914. His doctoral research focused on the metabolism of uric acid and allantoin.

Career and research

In 1914, Sumner joined the faculty of the Cornell University Medical College in Ithaca, New York, as an assistant professor of biochemistry. He later transferred to the Cornell University College of Agriculture, where he spent the majority of his career. His early work at Cornell University continued his interest in plant biochemistry, particularly the analysis of urease, an enzyme found in the jack bean. For over a decade, he dedicated himself to isolating this enzyme in pure form, a task many contemporaries believed was impossible because enzymes were thought to be elusive "vital forces" rather than discrete chemical substances.

Crystallization of enzymes

In 1926, after persistent effort, Sumner successfully isolated and crystallized urease from extracts of the jack bean. He demonstrated that these needle-like crystals possessed potent enzymatic activity and were composed of protein. This achievement, published in the Journal of Biological Chemistry, was met with initial skepticism from prominent figures in the field, including the German chemist Richard Willstätter, who championed the theory that enzymes were low-molecular-weight "active groups" adsorbed onto non-protein carriers. Sumner's rigorous evidence, which included showing that the crystalline protein lost its activity when denatured, gradually convinced the scientific community. He later went on to crystallize other enzymes, including catalase and peroxidase.

Nobel Prize in Chemistry

The profound significance of Sumner's work was internationally recognized two decades later. In 1946, he was awarded one-half of the Nobel Prize in Chemistry "for his discovery that enzymes can be crystallized." The other half was awarded jointly to John Howard Northrop and Wendell Meredith Stanley "for their preparation of enzymes and virus proteins in a pure form." The prize acknowledged that Sumner had provided the first definitive proof that an enzyme was a protein, a cornerstone of modern biochemistry. The award ceremony was held in Stockholm and presented by King Gustaf V of Sweden.

Later life and legacy

Following the Nobel Prize in Chemistry, Sumner continued his research and teaching at Cornell University. He authored the influential textbook The Chemistry and Methods of Enzymes and served as a consultant to the Office of Scientific Research and Development during World War II. He was elected to the United States National Academy of Sciences and received honorary degrees from institutions including Harvard University and the University of Brussels. Sumner died in 1955 in Buffalo, New York. His crystallization of urease is considered a landmark event, enabling the subsequent study of enzyme structure and mechanism by X-ray crystallography and fundamentally transforming the disciplines of enzymology and molecular biology.

Category:American biochemists Category:Nobel laureates in Chemistry Category:Harvard University alumni Category:Cornell University faculty Category:1887 births Category:1955 deaths