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tyrosine

(Encyclopedia)CE5 tyrosine tīˈrəsēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is not essential to the huma...

digestive system

(Encyclopedia)CE5 Digestive system digestive system, in the animal kingdom, a group of organs functioning in digestion and assimilation of food and elimination of wastes. Virtually all animals have a digestive ...

catalyst

(Encyclopedia)catalyst, substance that can cause a change in the rate of a chemical reaction without itself being consumed in the reaction; the changing of the reaction rate by use of a catalyst is called catalysis...

Skou, Jens Christian

(Encyclopedia)Skou, Jens Christian, 1918–2018, Danish chemist, M.D. Univ. of Copenhagen, 1944, Ph.D. Univ. of Aarhus, 1954. Skou was on the faculty at the Univ. of Aarhus, Denmark, from 1947 until he retired in 1...

chelating agents

(Encyclopedia)chelating agents kēˈlātĭng [key]. Certain organic compounds are capable of forming coordinate bonds (see chemical bond) with metals through two or more atoms of the organic compound; such organic ...

Nathans, Daniel

(Encyclopedia)Nathans, Daniel, 1928–99, American microbiologist, b. Wilmington, Del., M.D. Washington Univ., St. Louis, 1954. He became a professor at Johns Hopkins in 1962. Nathans worked with Werner Arber and H...

Northrop, John Howard

(Encyclopedia)Northrop, John Howard, 1891–1987, American chemist, b. Yonkers, N.Y., Ph.D. Columbia, 1915. He was a researcher at the Rockefeller Institute for Medical Research (now Rockefeller Univ.) from 1916 un...

Kornberg, Arthur

(Encyclopedia)Kornberg, Arthur, 1918–2007, American biochemist, b. Brooklyn, grad. College of the City of New York (B.S., 1937) and Univ. of Rochester (M.D., 1941). In 1942 he joined the U.S. Public Health Servic...

casein

(Encyclopedia)casein kāˈsēn [key], well-defined group of proteins found in milk, constituting about 80% of the proteins in cow's milk, but only 40% in human milk. Casein is a remarkably efficient nutrient, suppl...

polymerase chain reaction

(Encyclopedia)polymerase chain reaction pŏlˈĭmərāsˌ [key] (PCR), laboratory process in which a particular DNA segment from a mixture of DNA chains is rapidly replicated, producing a large, readily analyzed sa...