FISCHER, EDMOND H.

born April 6, 1920, Shanghai, China American biochemist who was the corecipient with Edwin G. Krebs of the 1992 Nobel Prize for Physiology or Medicine for their discoveries concerning reversible phosphorylation, a biochemical mechanism that governs the activities of cell proteins. The son of Swiss parents, Fischer earned a Ph.D. in chemistry from the University of Geneva in 1947 and conducted research there until 1953. That year he went to the United States, where he joined Krebs on the faculty of the University of Washington, Seattle. He became a full professor there in 1961. Fischer and Krebs made their discoveries in the mid-1950s while studying reversible phosphorylationi.e., the attachment or detachment of phosphate groups to cell proteins. The two men were the first to purify and characterize one of the enzymes (phosphorylase) involved in the process of phosphorylation. They also discovered the enzymes that catalyze the attachment and detachment of phosphate groups, known as protein kinases and phosphatase, respectively. In the decades following these initial discoveries, scientists were able to identify many other enzymes that regulate specific processes in cells, leading to explanations of the mechanisms controlling basic activities in all living cells.