James B. Sumner

American biochemist

• Born: November 19, 1887; Canton, Massachusetts
• Died: August 12, 1955; Buffalo, New York

Sumner crystallized the enzyme urease in 1926, the first successful example of such a chemical process. Subsequently, he was able to demonstrate that urease is a protein, providing the first evidence that enzymes are members of that organic category.

Primary field: Chemistry

Specialties: Biochemistry; physical chemistry

Early Life

James Batcheller Sumner was born November 19, 1887, the son of Charles and Elizabeth Kelly Sumner, textile manufacturers and members of a wealthy New England family. Several relatives were widely known for their cultural pursuits: Charles’s brother Frederick was a noted violinist, and his mother’s uncle James Batcheller was known as the “walking encyclopedia of Marblehead.” Sumner’s education began at the Eliot Grammar School and was continued at the Roxbury Latin School, both historical private schools with roots in the seventeenth century. Sumner’s education was briefly interrupted after a hunting accident resulting in the loss of his left arm below the elbow. Sumner had been left-handed, but he taught himself to use his right hand. Despite the loss of an arm, James continued to excel in sports, even becoming an expert in tennis.

Sumner entered Harvard College in 1906 with the intent of studying electrical engineering; however, interactions with several of Harvard’s most prominent chemists, in addition to discussions with his uncle Frederick, resulted in Sumner’s interests changing to chemistry, in which he received a degree in 1910. During this period, Sumner produced his first published article in the Journal of the American Chemical Society in 1910.

Sumner’s first job after college was working for his uncle Frederick at the Sumner Knitted Padding Company, a manufacturer of padding for tables and chairs. But after a few months he accepted an offer to teach at Mount Allison College in New Brunswick, Canada, as a professor of science. He taught two courses in chemistry and one course in physiology. This was followed by an assistantship in chemistry at Worcester Polytechnic Institute in Massachusetts.

In 1912, Sumner entered the medical school at Harvard to study biochemistry. His thesis advisor, Swedish American chemist Otto Folin, initially discouraged Sumner because of the loss of his arm, but Sumner was determined to become a chemist and overcame Folin’s reluctance. Sumner graduated with a master’s degree in 1913 and a PhD in biochemistry in 1914. His second professional publication, a description of the role of the liver in urea production, was published in the Journal of Biological Chemistry.

Life’s Work

Following graduation from Harvard, Sumner took a vacation in Europe, during which he received an appointment offer as assistant professor of biochemistry at Cornell Medical College. He would remain with Cornell University for his entire professional career, a time period spanning some forty years.

Sumner’s appointment included both teaching and research responsibilities. His first courses included lectures and laboratories in biochemistry taught to medical students, as well as a similar course for home economics students. Sumner’s research opportunities were limited, given the lack of proper laboratory equipment and facilities, as well as his having only one graduate assistant.

His interest in the purification of enzymes came almost by default. Given the limitations of the laboratory, Sumner decided to attempt a long shot—the isolation and purification of an enzyme. Since his previous graduate work involved the study of urease, an enzyme that promotes hydrolysis in the organic compound known as urea, studying this enzyme was the logical choice. Beginning in 1917 and throughout his long tenure at Cornell, Sumner’s work in characterizing urease would be the primary focus of most of his research. In 1920, Sumner was offered a Belgian American fellowship to work with biochemist Jean Effront at the medical school of the University of Brussels. Effront was a major figure in enzyme research but discouraged Sumner from attempting to purify urease, as he considered the project too difficult. Instead, Sumner decided to work with Edgard Zunz, a professor of pharmacology, who studied blood coagulation.

Since the jack bean contained large quantities of urease, Sumner chose the bushy American plant as the source for the enzyme. However, the task proved more difficult than Sumner initially had expected. Though he was able to isolate several globular proteins from the jack bean, it was only after testing a wide variety of solvents and washing procedures that he was able to precipitate pure crystals of the urease enzyme. In the summer of 1926, Sumner published his work in the Journal of Biological Chemistry.

Despite producing many papers on the same subject over the next five years—several of which were written with David B. Hand, who later became prominent in the area of food technology—few biochemists accepted Sumner’s idea that urease was a protein, and others insisted that the enzyme carrier was what had crystallized. It was only after John Northrop and Moses Kunitz at the Rockefeller Institute crystallized pepsin, trypsin, and chymotrypsin in a similar fashion that other biochemists acknowledged that the isolation and crystallization of enzymes, though difficult, could be accomplished. In 1929, following the first publications of his urease purification, Sumner was promoted to professor of biochemistry in the medical school.

Sumner continued his research on jack bean proteins even after the purification of urease. In 1936, he reported that concanavalin A, one of the proteins he had previously identified in the jack bean, was capable of agglutinating red blood cells. Several publications, in 1937 and 1938, reported the crystallization and characterization of another enzyme from the jack bean, catalase, which breaks down the substrate peroxide in the cell. Ironically, catalase is a nonprotein enzyme, but by the late 1930s the protein nature of most enzymes was accepted. In total, Sumner isolated and characterized over a dozen enzymes over the course of his scientific career. In 1946, Sumner, along with Northrop and Wendell M. Stanley, was awarded the Nobel Prize in Chemistry for his work in the purification of enzymes.

In 1947, he became the director of the enzyme chemistry laboratory at Cornell. In 1955, Sumner began preparations for retirement. He agreed to move temporarily to Belo Horizonte, Brazil, where he would help to establish an enzyme laboratory at the University of Minas Gerais School of Medicine.

While Sumner’s professional career included the authoring of several textbooks of biochemistry, primarily addressing the structure and functions of enzymes, he also contributed to the popular culture of the time. He was an expert cook, often surprising his students with questions about cooking that applied chemical principles. He was fluent in several languages, learning Portuguese while planning his move to Brazil.

During the summer of 1955, he was diagnosed with terminal cancer. He died on August 12, 1955. He was survived by his third wife, the former Mary Beyer, whom he married in 1943, and five children.

Impact

The immediate impact of Sumner’s work was the recognition that enzymes can occupy a class of organic molecules called proteins. In the aftermath of Sumner’s 1926 publication on the crystallization of urease, many biochemists refused to acknowledge that enzymes were proteins. The widespread skepticism resulted in part from the scientific community’s inability to reproduce Sumner’s experimental procedure; scientists had been trying unsuccessfully for years to crystallize enzymes. One German scientist reportedly expressed dismay that Sumner could isolate an enzyme when so many “great German chemists” had failed.

Once Sumner’s procedures were published, other scientists were able to carry out the crystallization of additional enzymes. In 1930, Northrop reported first the crystallization of pepsin and, later, trypsin.

Bibliography

Lesk, Arthur. Introduction to Protein Science: Architecture, Function, and Genomics. New York: Oxford UP, 2010. Print. Describes protein makeup and functions at both the macro and molecular levels, as well as more recent applications of protein expression in the cell.

Tanford, Charles, and Jaqueline Reynolds. Nature’s Robots: A History of Proteins. New York: Oxford UP, 2001. Print. Discusses the history behind the discovery and understanding of proteins and Sumner’s role in demonstrating the proteins as enzymes. Covers the controversies associated with his work.

Whitford, David. Proteins: Structure and Function. Hoboken: Wiley, 2005. Print. Moderately detailed discussion of amino acid and protein structure and functions. Includes the theory of protein crystallization, including references to Sumner’s work.