The oral biologist was an early expert on digestive enzymes
By Kirsten Weir | May 15, 2007
Patricia J. Keller, an oral biologist who helped to isolate and describe the structure of digestive enzymes, passed away in April at the age of 83.
"She was a superb scientist," said Murray Robinovitch, a student and later a colleague of Keller's at the University of Washington's oral biology department. Keller brought "biochemical finesse and sophistication ... to the field of oral biology," he said.
Keller studied biochemistry at the University of Detroit and later at Washington University in St. Louis, where she studied under Nobel prize-winning biochemists Gerty T. Cori and Carl F. Cori.
In 1954, Keller moved to Seattle to join the University of Washington's department of biochemistry as a postdoc -- the first woman to join the prestigious department. "She didn't pound her chest in terms of being a suffragette," Robinovitch said. But "she made it clear that it was an important goal in her life that women got equal consideration."
At the University of Washington, Keller worked closely with renowned biochemist Hans Neurath, isolating digestive enzymes from pancreatic juices and describing their structures. She loved her work, said Leo Sreebny, professor emeritus at the State University of New York at Stony Brook and former head of the department of oral biology at the University of Washington. But as the only woman in the department she had little opportunity for advancement, and felt people regarded her "as an icon more than a colleague," he said.
Sreebny, however, was struck by Keller's talent as a biochemist and invited her to join him in the fledgling department of oral pathology that he was establishing in the department of dentistry. She accepted, and shifted her interests from pancreatic enzymes to salivary enzymes. "It was a beautiful transition because exactly the same problems existed with saliva" as with pancreatic juices, Robinovitch said. At the time, biochemists were just beginning to identify and describe the myriad components of saliva, and Keller eagerly set out to "separate out the salivary enzymes and elucidate their structure and their function."
Keller's work in the basic sciences was so strong, Robinovitch said, it helped convince administrators to rename the department of oral pathology as the department of oral biology. She became a full professor in 1967, and later served as associate dean and acting chair of the department.
"She was a very excellent protein biochemist," said Anders Bennick, a professor emeritus of biochemistry at the University of Toronto who collaborated with Keller for many years. Keller's work, Bennick said, "was very fundamental, [and] it was very much cutting-edge." She soon established herself as an expert in the constituents of human parotid saliva, and eventually came to focus on a family of proteins known as basic proline-rich proteins. "So little was known of those proteins at that time," Bennick told The Scientist. "It was a question of studying the basic structure and function of proteins."
Basic proline-rich proteins "made up a considerable percentage of the total saliva and nobody had a clue what they did," Robinovitch said. Keller elucidated their structures and properties, giving Robinovitch the tools to eventually discover that the proteins have an inhibitory effect on the human immunodeficiency virus. "I would have never been able to do my work had it not been for the prior studies done by Pat," he said.
Keller "was a superb teacher, very patient, [and] had a terrific sense of humor," said Robert Redman, a staff oral pathologist at the VA Medical Hospital in Washington, DC, who did his graduate work in Keller's department at the University of Washington.
"She had," Robinovitch said, "a natural gift for doing science."
Links within this article:
JM Iverson et al, "The presence of chondroitin sulfate in parotid secretory granules and saliva of the rat," Cell Tissue Research, October 1987.
PJ Keller, GT Cori, "Purification and properties of the phosphorylase-rupturing enzyme," Journal of Biological Chemistry, May 1955.
Gerty T. Cori
Carl F. Cori
PJ Keller, E Cohen, H Neurath, "The proteins of bovine pancreatic juice. III. Incorporation in vivo of C14-arginine into trypsinogen, chymotrypsinogen A, and ribonuclease," Journal of Biological Chemistry, May 1961.
E. Russo: "In saliva veritas," The Scientist, March 29, 2004.
PJ Keller et al, "Proteins of bovine pancreatic juice," Journal of Biological Chemistry, August 1958.
DL Kauffman et al, "Alignment of amino acid and DNA sequences of human proline-rich proteins," Crit Rev Oral Biol Med. 1993
MR Robinovitch, "Anti-infectivity activity of human salivary secretions toward human immunodeficiency virus," Crit Rev Oral Biol Med. 1993
Regularly taking breaks from eating—for hours or days—can trigger changes both expected, such as in metabolic dynamics and inflammation, and surprising, as in immune system function and cancer progression.